Merge branch 'master' into soc-2021-curvessoc-2021-curves

60 files changed, 1102 insertions, 376 deletions

diff --git a/intern/cycles/blender/addon/engine.py b/intern/cycles/blender/addon/engine.py
index 48dd26cc622..b7713dc7110 100644
--- a/intern/cycles/blender/addon/engine.py
+++ b/intern/cycles/blender/addon/engine.py
@@ -228,6 +228,10 @@ def list_render_passes(scene, srl):
         else:
             yield (aov.name, "RGB", 'COLOR')
 
+    # Light groups.
+    for lightgroup in srl.lightgroups:
+        yield ("Combined_%s" % lightgroup.name, "RGB", 'COLOR')
+
 
 def register_passes(engine, scene, view_layer):
     for name, channelids, channeltype in list_render_passes(scene, view_layer):
diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py
index c86452e0a18..c97afa86fad 100644
--- a/intern/cycles/blender/addon/ui.py
+++ b/intern/cycles/blender/addon/ui.py
@@ -12,7 +12,7 @@ from bpy.types import Panel
 
 from bl_ui.properties_grease_pencil_common import GreasePencilSimplifyPanel
 from bl_ui.properties_render import draw_hair_settings
-from bl_ui.properties_view_layer import ViewLayerCryptomattePanel, ViewLayerAOVPanel
+from bl_ui.properties_view_layer import ViewLayerCryptomattePanel, ViewLayerAOVPanel, ViewLayerLightgroupsPanel
 
 class CyclesPresetPanel(PresetPanel, Panel):
     COMPAT_ENGINES = {'CYCLES'}
@@ -883,6 +883,12 @@ class CYCLES_RENDER_PT_passes_aov(CyclesButtonsPanel, ViewLayerAOVPanel):
     bl_parent_id = "CYCLES_RENDER_PT_passes"
 
 
+class CYCLES_RENDER_PT_passes_lightgroups(CyclesButtonsPanel, ViewLayerLightgroupsPanel):
+    bl_label = "Light Groups"
+    bl_context = "view_layer"
+    bl_parent_id = "CYCLES_RENDER_PT_passes"
+
+
 class CYCLES_PT_post_processing(CyclesButtonsPanel, Panel):
     bl_label = "Post Processing"
     bl_options = {'DEFAULT_CLOSED'}
@@ -1082,7 +1088,7 @@ class CYCLES_OBJECT_PT_shading(CyclesButtonsPanel, Panel):
             return False
 
         ob = context.object
-        return ob and has_geometry_visibility(ob) and ob.type != 'LIGHT'
+        return ob and has_geometry_visibility(ob)
 
     def draw(self, context):
         pass
@@ -1093,6 +1099,10 @@ class CYCLES_OBJECT_PT_shading_shadow_terminator(CyclesButtonsPanel, Panel):
     bl_parent_id = "CYCLES_OBJECT_PT_shading"
     bl_context = "object"
 
+    @classmethod
+    def poll(cls, context):
+        return context.object.type != 'LIGHT'
+
     def draw(self, context):
         layout = self.layout
         layout.use_property_split = True
@@ -1110,6 +1120,10 @@ class CYCLES_OBJECT_PT_shading_gi_approximation(CyclesButtonsPanel, Panel):
     bl_parent_id = "CYCLES_OBJECT_PT_shading"
     bl_context = "object"
 
+    @classmethod
+    def poll(cls, context):
+        return context.object.type != 'LIGHT'
+
     def draw(self, context):
         layout = self.layout
         layout.use_property_split = True
@@ -1132,7 +1146,7 @@ class CYCLES_OBJECT_PT_shading_caustics(CyclesButtonsPanel, Panel):
 
     @classmethod
     def poll(cls, context):
-        return CyclesButtonsPanel.poll(context) and not use_metal(context)
+        return CyclesButtonsPanel.poll(context) and not use_metal(context) and context.object.type != 'LIGHT'
 
     def draw(self, context):
         layout = self.layout
@@ -1147,6 +1161,23 @@ class CYCLES_OBJECT_PT_shading_caustics(CyclesButtonsPanel, Panel):
         col.prop(cob, "is_caustics_receiver")
 
 
+class CYCLES_OBJECT_PT_lightgroup(CyclesButtonsPanel, Panel):
+    bl_label = "Light Group"
+    bl_parent_id = "CYCLES_OBJECT_PT_shading"
+    bl_context = "object"
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+
+        ob = context.object
+
+        view_layer = context.view_layer
+
+        col = layout.column(align=True)
+        col.prop_search(ob, "lightgroup", view_layer, "lightgroups", text="Light Group")
+
+
 class CYCLES_OBJECT_PT_visibility(CyclesButtonsPanel, Panel):
     bl_label = "Visibility"
     bl_context = "object"
@@ -1399,10 +1430,14 @@ class CYCLES_WORLD_PT_surface(CyclesButtonsPanel, Panel):
         layout.use_property_split = True
 
         world = context.world
+        view_layer = context.view_layer
 
         if not panel_node_draw(layout, world, 'OUTPUT_WORLD', 'Surface'):
             layout.prop(world, "color")
 
+        col = layout.column(align=True)
+        col.prop_search(world, "lightgroup", view_layer, "lightgroups", text="Light Group")
+
 
 class CYCLES_WORLD_PT_volume(CyclesButtonsPanel, Panel):
     bl_label = "Volume"
@@ -2209,6 +2244,7 @@ classes = (
     CYCLES_RENDER_PT_passes_light,
     CYCLES_RENDER_PT_passes_crypto,
     CYCLES_RENDER_PT_passes_aov,
+    CYCLES_RENDER_PT_passes_lightgroups,
     CYCLES_RENDER_PT_filter,
     CYCLES_RENDER_PT_override,
     CYCLES_PT_post_processing,
@@ -2220,6 +2256,7 @@ classes = (
     CYCLES_OBJECT_PT_shading_shadow_terminator,
     CYCLES_OBJECT_PT_shading_gi_approximation,
     CYCLES_OBJECT_PT_shading_caustics,
+    CYCLES_OBJECT_PT_lightgroup,
     CYCLES_OBJECT_PT_visibility,
     CYCLES_OBJECT_PT_visibility_ray_visibility,
     CYCLES_OBJECT_PT_visibility_culling,
diff --git a/intern/cycles/blender/light.cpp b/intern/cycles/blender/light.cpp
index 04799443ceb..5359fa13505 100644
--- a/intern/cycles/blender/light.cpp
+++ b/intern/cycles/blender/light.cpp
@@ -143,6 +143,9 @@ void BlenderSync::sync_light(BL::Object &b_parent,
   light->set_use_scatter((visibility & PATH_RAY_VOLUME_SCATTER) != 0);
   light->set_is_shadow_catcher(b_ob_info.real_object.is_shadow_catcher());
 
+  /* lightgroup */
+  light->set_lightgroup(ustring(b_ob_info.real_object.lightgroup()));
+
   /* tag */
   light->tag_update(scene);
 }
diff --git a/intern/cycles/blender/object.cpp b/intern/cycles/blender/object.cpp
index 16a6b3454ed..d8f236e0641 100644
--- a/intern/cycles/blender/object.cpp
+++ b/intern/cycles/blender/object.cpp
@@ -343,6 +343,9 @@ Object *BlenderSync::sync_object(BL::Depsgraph &b_depsgraph,
       object->set_random_id(hash_uint2(hash_string(object->name.c_str()), 0));
     }
 
+    /* lightgroup */
+    object->set_lightgroup(ustring(b_ob.lightgroup()));
+
     object->tag_update(scene);
   }
 
diff --git a/intern/cycles/blender/shader.cpp b/intern/cycles/blender/shader.cpp
index 224cbea85f3..d3527567b96 100644
--- a/intern/cycles/blender/shader.cpp
+++ b/intern/cycles/blender/shader.cpp
@@ -1532,6 +1532,8 @@ void BlenderSync::sync_world(BL::Depsgraph &b_depsgraph, BL::SpaceView3D &b_v3d,
   background->set_use_shader(view_layer.use_background_shader ||
                              viewport_parameters.use_custom_shader());
 
+  background->set_lightgroup(ustring(b_world ? b_world.lightgroup() : ""));
+
   background->tag_update(scene);
 }
 
diff --git a/intern/cycles/blender/sync.cpp b/intern/cycles/blender/sync.cpp
index 8af2ee7a435..bd6bfafedeb 100644
--- a/intern/cycles/blender/sync.cpp
+++ b/intern/cycles/blender/sync.cpp
@@ -745,6 +745,20 @@ void BlenderSync::sync_render_passes(BL::RenderLayer &b_rlay, BL::ViewLayer &b_v
     }
   }
 
+  /* Light Group passes. */
+  BL::ViewLayer::lightgroups_iterator b_lightgroup_iter;
+  for (b_view_layer.lightgroups.begin(b_lightgroup_iter);
+       b_lightgroup_iter != b_view_layer.lightgroups.end();
+       ++b_lightgroup_iter) {
+    BL::Lightgroup b_lightgroup(*b_lightgroup_iter);
+
+    string name = string_printf("Combined_%s", b_lightgroup.name().c_str());
+
+    b_engine.add_pass(name.c_str(), 3, "RGB", b_view_layer.name().c_str());
+    Pass *pass = pass_add(scene, PASS_COMBINED, name.c_str(), PassMode::NOISY);
+    pass->set_lightgroup(ustring(b_lightgroup.name()));
+  }
+
   scene->film->set_pass_alpha_threshold(b_view_layer.pass_alpha_threshold());
 }
 
diff --git a/intern/cycles/integrator/pass_accessor.cpp b/intern/cycles/integrator/pass_accessor.cpp
index 0be3cf6860b..05318b7545b 100644
--- a/intern/cycles/integrator/pass_accessor.cpp
+++ b/intern/cycles/integrator/pass_accessor.cpp
@@ -18,7 +18,11 @@ CCL_NAMESPACE_BEGIN
  */
 
 PassAccessor::PassAccessInfo::PassAccessInfo(const BufferPass &pass)
-    : type(pass.type), mode(pass.mode), include_albedo(pass.include_albedo), offset(pass.offset)
+    : type(pass.type),
+      mode(pass.mode),
+      include_albedo(pass.include_albedo),
+      is_lightgroup(!pass.lightgroup.empty()),
+      offset(pass.offset)
 {
 }
 
@@ -127,7 +131,8 @@ bool PassAccessor::get_render_tile_pixels(const RenderBuffers *render_buffers,
 
   const PassType type = pass_access_info_.type;
   const PassMode mode = pass_access_info_.mode;
-  const PassInfo pass_info = Pass::get_info(type, pass_access_info_.include_albedo);
+  const PassInfo pass_info = Pass::get_info(
+      type, pass_access_info_.include_albedo, pass_access_info_.is_lightgroup);
   int num_written_components = pass_info.num_components;
 
   if (pass_info.num_components == 1) {
@@ -215,8 +220,8 @@ void PassAccessor::init_kernel_film_convert(KernelFilmConvert *kfilm_convert,
                                             const Destination &destination) const
 {
   const PassMode mode = pass_access_info_.mode;
-  const PassInfo &pass_info = Pass::get_info(pass_access_info_.type,
-                                             pass_access_info_.include_albedo);
+  const PassInfo &pass_info = Pass::get_info(
+      pass_access_info_.type, pass_access_info_.include_albedo, pass_access_info_.is_lightgroup);
 
   kfilm_convert->pass_offset = pass_access_info_.offset;
   kfilm_convert->pass_stride = buffer_params.pass_stride;
@@ -279,8 +284,8 @@ bool PassAccessor::set_render_tile_pixels(RenderBuffers *render_buffers, const S
     return false;
   }
 
-  const PassInfo pass_info = Pass::get_info(pass_access_info_.type,
-                                            pass_access_info_.include_albedo);
+  const PassInfo pass_info = Pass::get_info(
+      pass_access_info_.type, pass_access_info_.include_albedo, pass_access_info_.is_lightgroup);
 
   const BufferParams &buffer_params = render_buffers->params;
 
diff --git a/intern/cycles/integrator/pass_accessor.h b/intern/cycles/integrator/pass_accessor.h
index 7de1d03961b..683d3a35272 100644
--- a/intern/cycles/integrator/pass_accessor.h
+++ b/intern/cycles/integrator/pass_accessor.h
@@ -28,6 +28,7 @@ class PassAccessor {
     PassType type = PASS_NONE;
     PassMode mode = PassMode::NOISY;
     bool include_albedo = false;
+    bool is_lightgroup = false;
     int offset = -1;
 
     /* For the shadow catcher matte pass: whether to approximate shadow catcher pass into its
diff --git a/intern/cycles/kernel/film/accumulate.h b/intern/cycles/kernel/film/accumulate.h
index d6a385a4bff..e10acfd7eb5 100644
--- a/intern/cycles/kernel/film/accumulate.h
+++ b/intern/cycles/kernel/film/accumulate.h
@@ -320,12 +320,13 @@ ccl_device_inline void kernel_accum_combined_transparent_pass(KernelGlobals kg,
 }
 
 /* Write background or emission to appropriate pass. */
-ccl_device_inline void kernel_accum_emission_or_background_pass(KernelGlobals kg,
-                                                                ConstIntegratorState state,
-                                                                float3 contribution,
-                                                                ccl_global float *ccl_restrict
-                                                                    buffer,
-                                                                const int pass)
+ccl_device_inline void kernel_accum_emission_or_background_pass(
+    KernelGlobals kg,
+    ConstIntegratorState state,
+    float3 contribution,
+    ccl_global float *ccl_restrict buffer,
+    const int pass,
+    const int lightgroup = LIGHTGROUP_NONE)
 {
   if (!(kernel_data.film.light_pass_flag & PASS_ANY)) {
     return;
@@ -347,6 +348,11 @@ ccl_device_inline void kernel_accum_emission_or_background_pass(KernelGlobals kg
   }
 #  endif /* __DENOISING_FEATURES__ */
 
+  if (lightgroup != LIGHTGROUP_NONE && kernel_data.film.pass_lightgroup != PASS_UNUSED) {
+    kernel_write_pass_float3(buffer + kernel_data.film.pass_lightgroup + 3 * lightgroup,
+                             contribution);
+  }
+
   if (!(path_flag & PATH_RAY_ANY_PASS)) {
     /* Directly visible, write to emission or background pass. */
     pass_offset = pass;
@@ -449,6 +455,13 @@ ccl_device_inline void kernel_accum_light(KernelGlobals kg,
       return;
     }
 
+    /* Write lightgroup pass. LIGHTGROUP_NONE is ~0 so decode from unsigned to signed */
+    const int lightgroup = (int)(INTEGRATOR_STATE(state, shadow_path, lightgroup)) - 1;
+    if (lightgroup != LIGHTGROUP_NONE && kernel_data.film.pass_lightgroup != PASS_UNUSED) {
+      kernel_write_pass_float3(buffer + kernel_data.film.pass_lightgroup + 3 * lightgroup,
+                               contribution);
+    }
+
     if (kernel_data.kernel_features & KERNEL_FEATURE_LIGHT_PASSES) {
       int pass_offset = PASS_UNUSED;
 
@@ -566,15 +579,20 @@ ccl_device_inline void kernel_accum_background(KernelGlobals kg,
     kernel_accum_combined_transparent_pass(
         kg, path_flag, sample, contribution, transparent, buffer);
   }
-  kernel_accum_emission_or_background_pass(
-      kg, state, contribution, buffer, kernel_data.film.pass_background);
+  kernel_accum_emission_or_background_pass(kg,
+                                           state,
+                                           contribution,
+                                           buffer,
+                                           kernel_data.film.pass_background,
+                                           kernel_data.background.lightgroup);
 }
 
 /* Write emission to render buffer. */
 ccl_device_inline void kernel_accum_emission(KernelGlobals kg,
                                              ConstIntegratorState state,
                                              const float3 L,
-                                             ccl_global float *ccl_restrict render_buffer)
+                                             ccl_global float *ccl_restrict render_buffer,
+                                             const int lightgroup = LIGHTGROUP_NONE)
 {
   float3 contribution = L;
   kernel_accum_clamp(kg, &contribution, INTEGRATOR_STATE(state, path, bounce) - 1);
@@ -585,7 +603,7 @@ ccl_device_inline void kernel_accum_emission(KernelGlobals kg,
 
   kernel_accum_combined_pass(kg, path_flag, sample, contribution, buffer);
   kernel_accum_emission_or_background_pass(
-      kg, state, contribution, buffer, kernel_data.film.pass_emission);
+      kg, state, contribution, buffer, kernel_data.film.pass_emission, lightgroup);
 }
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/kernel/geom/object.h b/intern/cycles/kernel/geom/object.h
index 86c57c84b47..3faab7fa905 100644
--- a/intern/cycles/kernel/geom/object.h
+++ b/intern/cycles/kernel/geom/object.h
@@ -283,6 +283,26 @@ ccl_device_inline float object_pass_id(KernelGlobals kg, int object)
   return kernel_tex_fetch(__objects, object).pass_id;
 }
 
+/* Lightgroup of lamp */
+
+ccl_device_inline int lamp_lightgroup(KernelGlobals kg, int lamp)
+{
+  if (lamp == LAMP_NONE)
+    return LIGHTGROUP_NONE;
+
+  return kernel_tex_fetch(__lights, lamp).lightgroup;
+}
+
+/* Lightgroup of object */
+
+ccl_device_inline int object_lightgroup(KernelGlobals kg, int object)
+{
+  if (object == OBJECT_NONE)
+    return LIGHTGROUP_NONE;
+
+  return kernel_tex_fetch(__objects, object).lightgroup;
+}
+
 /* Per lamp random number for shader variation */
 
 ccl_device_inline float lamp_random_number(KernelGlobals kg, int lamp)
diff --git a/intern/cycles/kernel/integrator/shade_background.h b/intern/cycles/kernel/integrator/shade_background.h
index 4fd41121466..62b3ce1c15c 100644
--- a/intern/cycles/kernel/integrator/shade_background.h
+++ b/intern/cycles/kernel/integrator/shade_background.h
@@ -186,7 +186,8 @@ ccl_device_inline void integrate_distant_lights(KernelGlobals kg,
 
       /* Write to render buffer. */
       const float3 throughput = INTEGRATOR_STATE(state, path, throughput);
-      kernel_accum_emission(kg, state, throughput * light_eval, render_buffer);
+      kernel_accum_emission(
+          kg, state, throughput * light_eval, render_buffer, kernel_data.background.lightgroup);
     }
   }
 }
diff --git a/intern/cycles/kernel/integrator/shade_light.h b/intern/cycles/kernel/integrator/shade_light.h
index 4a519a76ed0..be926c78439 100644
--- a/intern/cycles/kernel/integrator/shade_light.h
+++ b/intern/cycles/kernel/integrator/shade_light.h
@@ -78,7 +78,7 @@ ccl_device_inline void integrate_light(KernelGlobals kg,
 
   /* Write to render buffer. */
   const float3 throughput = INTEGRATOR_STATE(state, path, throughput);
-  kernel_accum_emission(kg, state, throughput * light_eval, render_buffer);
+  kernel_accum_emission(kg, state, throughput * light_eval, render_buffer, ls.group);
 }
 
 ccl_device void integrator_shade_light(KernelGlobals kg,
diff --git a/intern/cycles/kernel/integrator/shade_surface.h b/intern/cycles/kernel/integrator/shade_surface.h
index c5dd9fe27f4..a9bf3b5b432 100644
--- a/intern/cycles/kernel/integrator/shade_surface.h
+++ b/intern/cycles/kernel/integrator/shade_surface.h
@@ -87,7 +87,8 @@ ccl_device_forceinline void integrate_surface_emission(KernelGlobals kg,
   }
 
   const float3 throughput = INTEGRATOR_STATE(state, path, throughput);
-  kernel_accum_emission(kg, state, throughput * L, render_buffer);
+  kernel_accum_emission(
+      kg, state, throughput * L, render_buffer, object_lightgroup(kg, sd->object));
 }
 #endif /* __EMISSION__ */
 
@@ -258,6 +259,12 @@ ccl_device_forceinline void integrate_surface_direct_light(KernelGlobals kg,
   if (kernel_data.kernel_features & KERNEL_FEATURE_SHADOW_PASS) {
     INTEGRATOR_STATE_WRITE(shadow_state, shadow_path, unshadowed_throughput) = throughput;
   }
+
+  /* Write Lightgroup, +1 as lightgroup is int but we need to encode into a uint8_t. */
+  INTEGRATOR_STATE_WRITE(
+      shadow_state, shadow_path, lightgroup) = (ls.type != LIGHT_BACKGROUND) ?
+                                                   ls.group + 1 :
+                                                   kernel_data.background.lightgroup + 1;
 }
 #endif
 
diff --git a/intern/cycles/kernel/integrator/shade_volume.h b/intern/cycles/kernel/integrator/shade_volume.h
index acda4b8e9d1..4a5015946aa 100644
--- a/intern/cycles/kernel/integrator/shade_volume.h
+++ b/intern/cycles/kernel/integrator/shade_volume.h
@@ -653,7 +653,8 @@ ccl_device_forceinline void volume_integrate_heterogeneous(
 
   /* Write accumulated emission. */
   if (!is_zero(accum_emission)) {
-    kernel_accum_emission(kg, state, accum_emission, render_buffer);
+    kernel_accum_emission(
+        kg, state, accum_emission, render_buffer, object_lightgroup(kg, sd->object));
   }
 
 #  ifdef __DENOISING_FEATURES__
@@ -833,6 +834,12 @@ ccl_device_forceinline void integrate_volume_direct_light(
     INTEGRATOR_STATE_WRITE(shadow_state, shadow_path, unshadowed_throughput) = throughput;
   }
 
+  /* Write Lightgroup, +1 as lightgroup is int but we need to encode into a uint8_t. */
+  INTEGRATOR_STATE_WRITE(
+      shadow_state, shadow_path, lightgroup) = (ls->type != LIGHT_BACKGROUND) ?
+                                                   ls->group + 1 :
+                                                   kernel_data.background.lightgroup + 1;
+
   integrator_state_copy_volume_stack_to_shadow(kg, shadow_state, state);
 }
 #  endif
diff --git a/intern/cycles/kernel/integrator/shadow_state_template.h b/intern/cycles/kernel/integrator/shadow_state_template.h
index 9308df53e46..eaee65ada40 100644
--- a/intern/cycles/kernel/integrator/shadow_state_template.h
+++ b/intern/cycles/kernel/integrator/shadow_state_template.h
@@ -38,6 +38,8 @@ KERNEL_STRUCT_MEMBER(shadow_path, packed_float3, pass_diffuse_weight, KERNEL_FEA
 KERNEL_STRUCT_MEMBER(shadow_path, packed_float3, pass_glossy_weight, KERNEL_FEATURE_LIGHT_PASSES)
 /* Number of intersections found by ray-tracing. */
 KERNEL_STRUCT_MEMBER(shadow_path, uint16_t, num_hits, KERNEL_FEATURE_PATH_TRACING)
+/* Light group. */
+KERNEL_STRUCT_MEMBER(shadow_path, uint8_t, lightgroup, KERNEL_FEATURE_PATH_TRACING)
 KERNEL_STRUCT_END(shadow_path)
 
 /********************************** Shadow Ray *******************************/
diff --git a/intern/cycles/kernel/light/light.h b/intern/cycles/kernel/light/light.h
index fb637008ca4..1df1615ed99 100644
--- a/intern/cycles/kernel/light/light.h
+++ b/intern/cycles/kernel/light/light.h
@@ -23,6 +23,7 @@ typedef struct LightSample {
   int prim;       /* primitive id for triangle/curve lights */
   int shader;     /* shader id */
   int lamp;       /* lamp id */
+  int group;      /* lightgroup */
   LightType type; /* type of light */
 } LightSample;
 
@@ -52,6 +53,7 @@ ccl_device_inline bool light_sample(KernelGlobals kg,
   ls->lamp = lamp;
   ls->u = randu;
   ls->v = randv;
+  ls->group = lamp_lightgroup(kg, lamp);
 
   if (in_volume_segment && (type == LIGHT_DISTANT || type == LIGHT_BACKGROUND)) {
     /* Distant lights in a volume get a dummy sample, position will not actually
@@ -413,6 +415,7 @@ ccl_device bool light_sample_from_distant_ray(KernelGlobals kg,
   ls->P = -ray_D;
   ls->Ng = -ray_D;
   ls->D = ray_D;
+  ls->group = lamp_lightgroup(kg, lamp);
 
   /* compute pdf */
   float invarea = klight->distant.invarea;
@@ -441,6 +444,7 @@ ccl_device bool light_sample_from_intersection(KernelGlobals kg,
   ls->t = isect->t;
   ls->P = ray_P + ray_D * ls->t;
   ls->D = ray_D;
+  ls->group = lamp_lightgroup(kg, lamp);
 
   if (type == LIGHT_SPOT) {
     const float3 center = make_float3(klight->co[0], klight->co[1], klight->co[2]);
@@ -706,6 +710,7 @@ ccl_device_forceinline void triangle_light_sample(KernelGlobals kg,
   ls->lamp = LAMP_NONE;
   ls->shader |= SHADER_USE_MIS;
   ls->type = LIGHT_TRIANGLE;
+  ls->group = object_lightgroup(kg, object);
 
   float distance_to_plane = fabsf(dot(N0, V[0] - P) / dot(N0, N0));
 
diff --git a/intern/cycles/kernel/types.h b/intern/cycles/kernel/types.h
index 00b5b007e11..9d9daaa0dda 100644
--- a/intern/cycles/kernel/types.h
+++ b/intern/cycles/kernel/types.h
@@ -46,6 +46,7 @@ CCL_NAMESPACE_BEGIN
 #define LAMP_NONE (~0)
 #define ID_NONE (0.0f)
 #define PASS_UNUSED (~0)
+#define LIGHTGROUP_NONE (~0)
 
 #define INTEGRATOR_SHADOW_ISECT_SIZE_CPU 1024U
 #define INTEGRATOR_SHADOW_ISECT_SIZE_GPU 4U
@@ -1108,6 +1109,7 @@ typedef struct KernelFilm {
 
   int pass_aov_color;
   int pass_aov_value;
+  int pass_lightgroup;
 
   /* XYZ to rendering color space transform. float4 instead of float3 to
    * ensure consistent padding/alignment across devices. */
@@ -1192,8 +1194,10 @@ typedef struct KernelBackground {
 
   int use_mis;
 
+  int lightgroup;
+
   /* Padding */
-  int pad1, pad2, pad3;
+  int pad1, pad2;
 } KernelBackground;
 static_assert_align(KernelBackground, 16);
 
@@ -1372,9 +1376,12 @@ typedef struct KernelObject {
 
   float ao_distance;
 
+  int lightgroup;
+
   uint visibility;
   int primitive_type;
-  int pad[2];
+
+  int pad1;
 } KernelObject;
 static_assert_align(KernelObject, 16);
 
@@ -1427,7 +1434,7 @@ typedef struct KernelLight {
   float random;
   float strength[3];
   int use_caustics;
-  float pad1;
+  int lightgroup;
   Transform tfm;
   Transform itfm;
   union {
diff --git a/intern/cycles/scene/background.cpp b/intern/cycles/scene/background.cpp
index 1c3a9f9358d..bffc8895bfd 100644
--- a/intern/cycles/scene/background.cpp
+++ b/intern/cycles/scene/background.cpp
@@ -32,6 +32,8 @@ NODE_DEFINE(Background)
 
   SOCKET_NODE(shader, "Shader", Shader::get_node_type());
 
+  SOCKET_STRING(lightgroup, "Light Group", ustring());
+
   return type;
 }
 
@@ -101,6 +103,15 @@ void Background::device_update(Device *device, DeviceScene *dscene, Scene *scene
       kbackground->surface_shader |= SHADER_EXCLUDE_CAMERA;
   }
 
+  /* Light group. */
+  auto it = scene->lightgroups.find(lightgroup);
+  if (it != scene->lightgroups.end()) {
+    kbackground->lightgroup = it->second;
+  }
+  else {
+    kbackground->lightgroup = LIGHTGROUP_NONE;
+  }
+
   clear_modified();
 }
 
diff --git a/intern/cycles/scene/background.h b/intern/cycles/scene/background.h
index bbffce6e30a..50b4368d708 100644
--- a/intern/cycles/scene/background.h
+++ b/intern/cycles/scene/background.h
@@ -30,6 +30,8 @@ class Background : public Node {
 
   NODE_SOCKET_API(float, volume_step_size)
 
+  NODE_SOCKET_API(ustring, lightgroup)
+
   Background();
   ~Background();
 
diff --git a/intern/cycles/scene/film.cpp b/intern/cycles/scene/film.cpp
index e17c839d60b..c3b126544c4 100644
--- a/intern/cycles/scene/film.cpp
+++ b/intern/cycles/scene/film.cpp
@@ -175,6 +175,7 @@ void Film::device_update(Device *device, DeviceScene *dscene, Scene *scene)
   kfilm->pass_volume_direct = PASS_UNUSED;
   kfilm->pass_volume_indirect = PASS_UNUSED;
   kfilm->pass_shadow = PASS_UNUSED;
+  kfilm->pass_lightgroup = PASS_UNUSED;
 
   /* Mark passes as unused so that the kernel knows the pass is inaccessible. */
   kfilm->pass_denoising_normal = PASS_UNUSED;
@@ -189,6 +190,7 @@ void Film::device_update(Device *device, DeviceScene *dscene, Scene *scene)
   bool have_cryptomatte = false;
   bool have_aov_color = false;
   bool have_aov_value = false;
+  bool have_lightgroup = false;
 
   for (size_t i = 0; i < scene->passes.size(); i++) {
     const Pass *pass = scene->passes[i];
@@ -223,6 +225,15 @@ void Film::device_update(Device *device, DeviceScene *dscene, Scene *scene)
       assert(pass->get_type() <= PASS_CATEGORY_BAKE_END);
     }
 
+    if (pass->get_lightgroup() != ustring()) {
+      if (!have_lightgroup) {
+        kfilm->pass_lightgroup = kfilm->pass_stride;
+        have_lightgroup = true;
+      }
+      kfilm->pass_stride += pass->get_info().num_components;
+      continue;
+    }
+
     switch (pass->get_type()) {
       case PASS_COMBINED:
         kfilm->pass_combined = kfilm->pass_stride;
@@ -414,6 +425,26 @@ int Film::get_aov_offset(Scene *scene, string name, bool &is_color)
   return -1;
 }
 
+bool Film::update_lightgroups(Scene *scene)
+{
+  map<ustring, int> lightgroups;
+  int i = 0;
+  foreach (const Pass *pass, scene->passes) {
+    ustring lightgroup = pass->get_lightgroup();
+    if (!lightgroup.empty()) {
+      if (!lightgroups.count(lightgroup)) {
+        lightgroups[lightgroup] = i++;
+      }
+    }
+  }
+  if (scene->lightgroups != lightgroups) {
+    scene->lightgroups = lightgroups;
+    return true;
+  }
+
+  return false;
+}
+
 void Film::update_passes(Scene *scene, bool add_sample_count_pass)
 {
   const Background *background = scene->background;
@@ -580,11 +611,19 @@ void Film::remove_auto_passes(Scene *scene)
 
 static bool compare_pass_order(const Pass *a, const Pass *b)
 {
+  /* On the highest level, sort by number of components.
+   * Within passes of the same component count, sort so that all non-lightgroup passes come first.
+   * Within that group, sort by type. */
   const int num_components_a = a->get_info().num_components;
   const int num_components_b = b->get_info().num_components;
 
   if (num_components_a == num_components_b) {
-    return (a->get_type() < b->get_type());
+    const int is_lightgroup_a = !a->get_lightgroup().empty();
+    const int is_lightgroup_b = !b->get_lightgroup().empty();
+    if (is_lightgroup_a == is_lightgroup_b) {
+      return (a->get_type() < b->get_type());
+    }
+    return is_lightgroup_b;
   }
 
   return num_components_a > num_components_b;
diff --git a/intern/cycles/scene/film.h b/intern/cycles/scene/film.h
index 43597b0fc79..f1e3237eb9e 100644
--- a/intern/cycles/scene/film.h
+++ b/intern/cycles/scene/film.h
@@ -68,6 +68,8 @@ class Film : public Node {
 
   int get_aov_offset(Scene *scene, string name, bool &is_color);
 
+  bool update_lightgroups(Scene *scene);
+
   /* Update passes so that they contain all passes required for the configured functionality.
    *
    * If `add_sample_count_pass` is true then the SAMPLE_COUNT pass is ensured to be added. */
diff --git a/intern/cycles/scene/light.cpp b/intern/cycles/scene/light.cpp
index 85a7f37994c..5e311d3051f 100644
--- a/intern/cycles/scene/light.cpp
+++ b/intern/cycles/scene/light.cpp
@@ -134,6 +134,8 @@ NODE_DEFINE(Light)
 
   SOCKET_NODE(shader, "Shader", Shader::get_node_type());
 
+  SOCKET_STRING(lightgroup, "Light Group", ustring());
+
   return type;
 }
 
@@ -902,6 +904,14 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
     klights[light_index].tfm = light->tfm;
     klights[light_index].itfm = transform_inverse(light->tfm);
 
+    auto it = scene->lightgroups.find(light->lightgroup);
+    if (it != scene->lightgroups.end()) {
+      klights[light_index].lightgroup = it->second;
+    }
+    else {
+      klights[light_index].lightgroup = LIGHTGROUP_NONE;
+    }
+
     light_index++;
   }
 
diff --git a/intern/cycles/scene/light.h b/intern/cycles/scene/light.h
index 25190f6fb63..5b852f210fc 100644
--- a/intern/cycles/scene/light.h
+++ b/intern/cycles/scene/light.h
@@ -71,6 +71,8 @@ class Light : public Node {
   NODE_SOCKET_API(int, max_bounces)
   NODE_SOCKET_API(uint, random_id)
 
+  NODE_SOCKET_API(ustring, lightgroup)
+
   void tag_update(Scene *scene);
 
   /* Check whether the light has contribution the scene. */
diff --git a/intern/cycles/scene/object.cpp b/intern/cycles/scene/object.cpp
index 9b19169880a..55d89fc3673 100644
--- a/intern/cycles/scene/object.cpp
+++ b/intern/cycles/scene/object.cpp
@@ -98,6 +98,8 @@ NODE_DEFINE(Object)
 
   SOCKET_FLOAT(ao_distance, "AO Distance", 0.0f);
 
+  SOCKET_STRING(lightgroup, "Light Group", ustring());
+
   return type;
 }
 
@@ -393,7 +395,8 @@ static float object_volume_density(const Transform &tfm, Geometry *geom)
 
 void ObjectManager::device_update_object_transform(UpdateObjectTransformState *state,
                                                    Object *ob,
-                                                   bool update_all)
+                                                   bool update_all,
+                                                   const Scene *scene)
 {
   KernelObject &kobject = state->objects[ob->index];
   Transform *object_motion_pass = state->object_motion_pass;
@@ -532,6 +535,15 @@ void ObjectManager::device_update_object_transform(UpdateObjectTransformState *s
   if (geom->geometry_type == Geometry::HAIR) {
     state->have_curves = true;
   }
+
+  /* Light group. */
+  auto it = scene->lightgroups.find(ob->lightgroup);
+  if (it != scene->lightgroups.end()) {
+    kobject.lightgroup = it->second;
+  }
+  else {
+    kobject.lightgroup = LIGHTGROUP_NONE;
+  }
 }
 
 void ObjectManager::device_update_prim_offsets(Device *device, DeviceScene *dscene, Scene *scene)
@@ -618,7 +630,7 @@ void ObjectManager::device_update_transforms(DeviceScene *dscene, Scene *scene,
                [&](const blocked_range<size_t> &r) {
                  for (size_t i = r.begin(); i != r.end(); i++) {
                    Object *ob = state.scene->objects[i];
-                   device_update_object_transform(&state, ob, update_all);
+                   device_update_object_transform(&state, ob, update_all, scene);
                  }
                });
 
diff --git a/intern/cycles/scene/object.h b/intern/cycles/scene/object.h
index 561ecd4e7e9..c41f1416180 100644
--- a/intern/cycles/scene/object.h
+++ b/intern/cycles/scene/object.h
@@ -66,6 +66,8 @@ class Object : public Node {
 
   NODE_SOCKET_API(float, ao_distance)
 
+  NODE_SOCKET_API(ustring, lightgroup)
+
   /* Set during device update. */
   bool intersects_volume;
 
@@ -169,7 +171,8 @@ class ObjectManager {
  protected:
   void device_update_object_transform(UpdateObjectTransformState *state,
                                       Object *ob,
-                                      bool update_all);
+                                      bool update_all,
+                                      const Scene *scene);
   void device_update_object_transform_task(UpdateObjectTransformState *state);
   bool device_update_object_transform_pop_work(UpdateObjectTransformState *state,
                                                int *start_index,
diff --git a/intern/cycles/scene/pass.cpp b/intern/cycles/scene/pass.cpp
index 41730cb189d..5f5b19e710d 100644
--- a/intern/cycles/scene/pass.cpp
+++ b/intern/cycles/scene/pass.cpp
@@ -124,6 +124,7 @@ NODE_DEFINE(Pass)
   SOCKET_ENUM(mode, "Mode", *pass_mode_enum, static_cast<int>(PassMode::DENOISED));
   SOCKET_STRING(name, "Name", ustring());
   SOCKET_BOOLEAN(include_albedo, "Include Albedo", false);
+  SOCKET_STRING(lightgroup, "Light Group", ustring());
 
   return type;
 }
@@ -134,7 +135,7 @@ Pass::Pass() : Node(get_node_type()), is_auto_(false)
 
 PassInfo Pass::get_info() const
 {
-  return get_info(type, include_albedo);
+  return get_info(type, include_albedo, !lightgroup.empty());
 }
 
 bool Pass::is_written() const
@@ -142,7 +143,7 @@ bool Pass::is_written() const
   return get_info().is_written;
 }
 
-PassInfo Pass::get_info(const PassType type, const bool include_albedo)
+PassInfo Pass::get_info(const PassType type, const bool include_albedo, const bool is_lightgroup)
 {
   PassInfo pass_info;
 
@@ -157,9 +158,9 @@ PassInfo Pass::get_info(const PassType type, const bool include_albedo)
       pass_info.num_components = 0;
       break;
     case PASS_COMBINED:
-      pass_info.num_components = 4;
+      pass_info.num_components = is_lightgroup ? 3 : 4;
       pass_info.use_exposure = true;
-      pass_info.support_denoise = true;
+      pass_info.support_denoise = !is_lightgroup;
       break;
     case PASS_DEPTH:
       pass_info.num_components = 1;
@@ -369,13 +370,16 @@ const Pass *Pass::find(const vector<Pass *> &passes, const string &name)
   return nullptr;
 }
 
-const Pass *Pass::find(const vector<Pass *> &passes, PassType type, PassMode mode)
+const Pass *Pass::find(const vector<Pass *> &passes,
+                       PassType type,
+                       PassMode mode,
+                       const ustring &lightgroup)
 {
   for (const Pass *pass : passes) {
-    if (pass->get_type() != type || pass->get_mode() != mode) {
+    if (pass->get_type() != type || pass->get_mode() != mode ||
+        pass->get_lightgroup() != lightgroup) {
       continue;
     }
-
     return pass;
   }
 
diff --git a/intern/cycles/scene/pass.h b/intern/cycles/scene/pass.h
index c12df007b5d..e0689eba688 100644
--- a/intern/cycles/scene/pass.h
+++ b/intern/cycles/scene/pass.h
@@ -53,6 +53,7 @@ class Pass : public Node {
   NODE_SOCKET_API(PassMode, mode)
   NODE_SOCKET_API(ustring, name)
   NODE_SOCKET_API(bool, include_albedo)
+  NODE_SOCKET_API(ustring, lightgroup)
 
   Pass();
 
@@ -72,7 +73,9 @@ class Pass : public Node {
   static const NodeEnum *get_type_enum();
   static const NodeEnum *get_mode_enum();
 
-  static PassInfo get_info(PassType type, const bool include_albedo = false);
+  static PassInfo get_info(PassType type,
+                           const bool include_albedo = false,
+                           const bool is_lightgroup = false);
 
   static bool contains(const vector<Pass *> &passes, PassType type);
 
@@ -80,7 +83,8 @@ class Pass : public Node {
   static const Pass *find(const vector<Pass *> &passes, const string &name);
   static const Pass *find(const vector<Pass *> &passes,
                           PassType type,
-                          PassMode mode = PassMode::NOISY);
+                          PassMode mode = PassMode::NOISY,
+                          const ustring &lightgroup = ustring());
 
   /* Returns PASS_UNUSED if there is no corresponding pass. */
   static int get_offset(const vector<Pass *> &passes, const Pass *pass);
diff --git a/intern/cycles/scene/scene.cpp b/intern/cycles/scene/scene.cpp
index 359e2d8e2c3..b6b53004816 100644
--- a/intern/cycles/scene/scene.cpp
+++ b/intern/cycles/scene/scene.cpp
@@ -251,6 +251,11 @@ void Scene::device_update(Device *device_, Progress &progress)
    * - Lookup tables are done a second time to handle film tables
    */
 
+  if (film->update_lightgroups(this)) {
+    light_manager->tag_update(this, ccl::LightManager::LIGHT_MODIFIED);
+    object_manager->tag_update(this, ccl::ObjectManager::OBJECT_MODIFIED);
+  }
+
   progress.set_status("Updating Shaders");
   shader_manager->device_update(device, &dscene, this, progress);
 
diff --git a/intern/cycles/scene/scene.h b/intern/cycles/scene/scene.h
index e1b36899302..9e3e8d61b80 100644
--- a/intern/cycles/scene/scene.h
+++ b/intern/cycles/scene/scene.h
@@ -197,6 +197,9 @@ class Scene : public NodeOwner {
   /* Optional name. Is used for logging and reporting. */
   string name;
 
+  /* Maps from Light group names to their pass ID. */
+  map<ustring, int> lightgroups;
+
   /* data */
   BVH *bvh;
   Camera *camera;
diff --git a/intern/cycles/session/buffers.cpp b/intern/cycles/session/buffers.cpp
index f9893ed1e1c..3bbc205ca7a 100644
--- a/intern/cycles/session/buffers.cpp
+++ b/intern/cycles/session/buffers.cpp
@@ -49,6 +49,7 @@ NODE_DEFINE(BufferPass)
   SOCKET_ENUM(mode, "Mode", *pass_mode_enum, static_cast<int>(PassMode::DENOISED));
   SOCKET_STRING(name, "Name", ustring());
   SOCKET_BOOLEAN(include_albedo, "Include Albedo", false);
+  SOCKET_STRING(lightgroup, "Light Group", ustring());
 
   SOCKET_INT(offset, "Offset", -1);
 
@@ -64,13 +65,14 @@ BufferPass::BufferPass(const Pass *scene_pass)
       type(scene_pass->get_type()),
       mode(scene_pass->get_mode()),
       name(scene_pass->get_name()),
-      include_albedo(scene_pass->get_include_albedo())
+      include_albedo(scene_pass->get_include_albedo()),
+      lightgroup(scene_pass->get_lightgroup())
 {
 }
 
 PassInfo BufferPass::get_info() const
 {
-  return Pass::get_info(type, include_albedo);
+  return Pass::get_info(type, include_albedo, !lightgroup.empty());
 }
 
 /* --------------------------------------------------------------------
diff --git a/intern/cycles/session/buffers.h b/intern/cycles/session/buffers.h
index 1c4ec81e427..a8278388a28 100644
--- a/intern/cycles/session/buffers.h
+++ b/intern/cycles/session/buffers.h
@@ -30,6 +30,7 @@ class BufferPass : public Node {
   PassMode mode = PassMode::NOISY;
   ustring name;
   bool include_albedo = false;
+  ustring lightgroup;
 
   int offset = -1;
 
@@ -49,7 +50,8 @@ class BufferPass : public Node {
   inline bool operator==(const BufferPass &other) const
   {
     return type == other.type && mode == other.mode && name == other.name &&
-           include_albedo == other.include_albedo && offset == other.offset;
+           include_albedo == other.include_albedo && lightgroup == other.lightgroup &&
+           offset == other.offset;
   }
   inline bool operator!=(const BufferPass &other) const
   {
diff --git a/release/scripts/startup/bl_ui/properties_view_layer.py b/release/scripts/startup/bl_ui/properties_view_layer.py
index 4dee7b73faf..83e797583ad 100644
--- a/release/scripts/startup/bl_ui/properties_view_layer.py
+++ b/release/scripts/startup/bl_ui/properties_view_layer.py
@@ -187,6 +187,33 @@ class VIEWLAYER_PT_layer_passes_cryptomatte(ViewLayerCryptomattePanel, Panel):
     COMPAT_ENGINES = {'BLENDER_EEVEE'}
 
 
+class ViewLayerLightgroupsPanel(ViewLayerButtonsPanel, Panel):
+    bl_label = "Light Groups"
+
+    def draw(self, context):
+        layout = self.layout
+
+        layout.use_property_split = True
+        layout.use_property_decorate = False
+
+        view_layer = context.view_layer
+
+        row = layout.row()
+        col = row.column()
+        col.template_list("UI_UL_list", "lightgroups", view_layer,
+                          "lightgroups", view_layer, "active_lightgroup_index", rows=2)
+
+        col = row.column()
+        sub = col.column(align=True)
+        sub.operator("scene.view_layer_add_lightgroup", icon='ADD', text="")
+        sub.operator("scene.view_layer_remove_lightgroup", icon='REMOVE', text="")
+
+
+class VIEWLAYER_PT_layer_passes_lightgroups(ViewLayerLightgroupsPanel):
+    bl_parent_id = "VIEWLAYER_PT_layer_passes"
+    COMPAT_ENGINES = {'CYCLES'}
+
+
 classes = (
     VIEWLAYER_PT_layer,
     VIEWLAYER_PT_layer_passes,
@@ -195,6 +222,7 @@ classes = (
     VIEWLAYER_PT_eevee_layer_passes_effects,
     VIEWLAYER_PT_layer_passes_cryptomatte,
     VIEWLAYER_PT_layer_passes_aov,
+    VIEWLAYER_PT_layer_passes_lightgroups,
     VIEWLAYER_UL_aov,
 )
 
diff --git a/source/blender/blenkernel/BKE_layer.h b/source/blender/blenkernel/BKE_layer.h
index c877035830c..4a3917dafee 100644
--- a/source/blender/blenkernel/BKE_layer.h
+++ b/source/blender/blenkernel/BKE_layer.h
@@ -8,6 +8,7 @@
 
 #include "BKE_collection.h"
 
+#include "DNA_layer_types.h"
 #include "DNA_listBase.h"
 
 #ifdef __cplusplus
@@ -581,6 +582,21 @@ bool BKE_view_layer_has_valid_aov(struct ViewLayer *view_layer);
 struct ViewLayer *BKE_view_layer_find_with_aov(struct Scene *scene,
                                                struct ViewLayerAOV *view_layer_aov);
 
+struct ViewLayerLightgroup *BKE_view_layer_add_lightgroup(struct ViewLayer *view_layer);
+void BKE_view_layer_remove_lightgroup(struct ViewLayer *view_layer,
+                                      struct ViewLayerLightgroup *lightgroup);
+void BKE_view_layer_set_active_lightgroup(struct ViewLayer *view_layer,
+                                          struct ViewLayerLightgroup *lightgroup);
+struct ViewLayer *BKE_view_layer_find_with_lightgroup(
+    struct Scene *scene, struct ViewLayerLightgroup *view_layer_lightgroup);
+void BKE_view_layer_rename_lightgroup(ViewLayer *view_layer,
+                                      ViewLayerLightgroup *lightgroup,
+                                      const char *name);
+
+void BKE_lightgroup_membership_get(struct LightgroupMembership *lgm, char *value);
+int BKE_lightgroup_membership_length(struct LightgroupMembership *lgm);
+void BKE_lightgroup_membership_set(struct LightgroupMembership **lgm, const char *value);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/blenkernel/intern/layer.c b/source/blender/blenkernel/intern/layer.c
index ccff4dbed03..c99bf885074 100644
--- a/source/blender/blenkernel/intern/layer.c
+++ b/source/blender/blenkernel/intern/layer.c
@@ -266,6 +266,8 @@ void BKE_view_layer_free_ex(ViewLayer *view_layer, const bool do_id_user)
   BLI_freelistN(&view_layer->drawdata);
   BLI_freelistN(&view_layer->aovs);
   view_layer->active_aov = NULL;
+  BLI_freelistN(&view_layer->lightgroups);
+  view_layer->active_lightgroup = NULL;
 
   MEM_SAFE_FREE(view_layer->stats);
 
@@ -428,6 +430,29 @@ static void layer_aov_copy_data(ViewLayer *view_layer_dst,
   }
 }
 
+static void layer_lightgroup_copy_data(ViewLayer *view_layer_dst,
+                                       const ViewLayer *view_layer_src,
+                                       ListBase *lightgroups_dst,
+                                       const ListBase *lightgroups_src)
+{
+  if (lightgroups_src != NULL) {
+    BLI_duplicatelist(lightgroups_dst, lightgroups_src);
+  }
+
+  ViewLayerLightgroup *lightgroup_dst = lightgroups_dst->first;
+  const ViewLayerLightgroup *lightgroup_src = lightgroups_src->first;
+
+  while (lightgroup_dst != NULL) {
+    BLI_assert(lightgroup_src);
+    if (lightgroup_src == view_layer_src->active_lightgroup) {
+      view_layer_dst->active_lightgroup = lightgroup_dst;
+    }
+
+    lightgroup_dst = lightgroup_dst->next;
+    lightgroup_src = lightgroup_src->next;
+  }
+}
+
 static void layer_collections_copy_data(ViewLayer *view_layer_dst,
                                         const ViewLayer *view_layer_src,
                                         ListBase *layer_collections_dst,
@@ -496,6 +521,10 @@ void BKE_view_layer_copy_data(Scene *scene_dst,
   layer_aov_copy_data(
       view_layer_dst, view_layer_src, &view_layer_dst->aovs, &view_layer_src->aovs);
 
+  BLI_listbase_clear(&view_layer_dst->lightgroups);
+  layer_lightgroup_copy_data(
+      view_layer_dst, view_layer_src, &view_layer_dst->lightgroups, &view_layer_src->lightgroups);
+
   if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
     id_us_plus((ID *)view_layer_dst->mat_override);
   }
@@ -2256,6 +2285,9 @@ void BKE_view_layer_blend_write(BlendWriter *writer, ViewLayer *view_layer)
   LISTBASE_FOREACH (ViewLayerAOV *, aov, &view_layer->aovs) {
     BLO_write_struct(writer, ViewLayerAOV, aov);
   }
+  LISTBASE_FOREACH (ViewLayerLightgroup *, lightgroup, &view_layer->lightgroups) {
+    BLO_write_struct(writer, ViewLayerLightgroup, lightgroup);
+  }
   write_layer_collections(writer, &view_layer->layer_collections);
 }
 
@@ -2294,6 +2326,9 @@ void BKE_view_layer_blend_read_data(BlendDataReader *reader, ViewLayer *view_lay
   BLO_read_list(reader, &view_layer->aovs);
   BLO_read_data_address(reader, &view_layer->active_aov);
 
+  BLO_read_list(reader, &view_layer->lightgroups);
+  BLO_read_data_address(reader, &view_layer->active_lightgroup);
+
   BLI_listbase_clear(&view_layer->drawdata);
   view_layer->object_bases_array = NULL;
   view_layer->object_bases_hash = NULL;
@@ -2471,4 +2506,117 @@ ViewLayer *BKE_view_layer_find_with_aov(struct Scene *scene, struct ViewLayerAOV
   return NULL;
 }
 
+/* -------------------------------------------------------------------- */
+/** \name Light Groups
+ * \{ */
+
+static void viewlayer_lightgroup_make_name_unique(ViewLayer *view_layer,
+                                                  ViewLayerLightgroup *lightgroup)
+{
+  /* Don't allow dots, it's incompatible with OpenEXR convention to store channels
+   * as "layer.pass.channel". */
+  BLI_str_replace_char(lightgroup->name, '.', '_');
+  BLI_uniquename(&view_layer->lightgroups,
+                 lightgroup,
+                 DATA_("Lightgroup"),
+                 '_',
+                 offsetof(ViewLayerLightgroup, name),
+                 sizeof(lightgroup->name));
+}
+
+static void viewlayer_lightgroup_active_set(ViewLayer *view_layer, ViewLayerLightgroup *lightgroup)
+{
+  if (lightgroup != NULL) {
+    BLI_assert(BLI_findindex(&view_layer->lightgroups, lightgroup) != -1);
+    view_layer->active_lightgroup = lightgroup;
+  }
+  else {
+    view_layer->active_lightgroup = NULL;
+  }
+}
+
+struct ViewLayerLightgroup *BKE_view_layer_add_lightgroup(struct ViewLayer *view_layer)
+{
+  ViewLayerLightgroup *lightgroup;
+  lightgroup = MEM_callocN(sizeof(ViewLayerLightgroup), __func__);
+  BLI_strncpy(lightgroup->name, DATA_("Lightgroup"), sizeof(lightgroup->name));
+  BLI_addtail(&view_layer->lightgroups, lightgroup);
+  viewlayer_lightgroup_active_set(view_layer, lightgroup);
+  viewlayer_lightgroup_make_name_unique(view_layer, lightgroup);
+  return lightgroup;
+}
+
+void BKE_view_layer_remove_lightgroup(ViewLayer *view_layer, ViewLayerLightgroup *lightgroup)
+{
+  BLI_assert(BLI_findindex(&view_layer->lightgroups, lightgroup) != -1);
+  BLI_assert(lightgroup != NULL);
+  if (view_layer->active_lightgroup == lightgroup) {
+    if (lightgroup->next) {
+      viewlayer_lightgroup_active_set(view_layer, lightgroup->next);
+    }
+    else {
+      viewlayer_lightgroup_active_set(view_layer, lightgroup->prev);
+    }
+  }
+  BLI_freelinkN(&view_layer->lightgroups, lightgroup);
+}
+
+void BKE_view_layer_set_active_lightgroup(ViewLayer *view_layer, ViewLayerLightgroup *lightgroup)
+{
+  viewlayer_lightgroup_active_set(view_layer, lightgroup);
+}
+
+ViewLayer *BKE_view_layer_find_with_lightgroup(struct Scene *scene,
+                                               struct ViewLayerLightgroup *lightgroup)
+{
+  LISTBASE_FOREACH (ViewLayer *, view_layer, &scene->view_layers) {
+    if (BLI_findindex(&view_layer->lightgroups, lightgroup) != -1) {
+      return view_layer;
+    }
+  }
+  return NULL;
+}
+
+void BKE_view_layer_rename_lightgroup(ViewLayer *view_layer,
+                                      ViewLayerLightgroup *lightgroup,
+                                      const char *name)
+{
+  BLI_strncpy_utf8(lightgroup->name, name, sizeof(lightgroup->name));
+  viewlayer_lightgroup_make_name_unique(view_layer, lightgroup);
+}
+
+void BKE_lightgroup_membership_get(struct LightgroupMembership *lgm, char *name)
+{
+  if (lgm != NULL) {
+    BLI_strncpy(name, lgm->name, sizeof(lgm->name));
+  }
+  else {
+    name[0] = '\0';
+  }
+}
+
+int BKE_lightgroup_membership_length(struct LightgroupMembership *lgm)
+{
+  if (lgm != NULL) {
+    return strlen(lgm->name);
+  }
+  return 0;
+}
+
+void BKE_lightgroup_membership_set(struct LightgroupMembership **lgm, const char *name)
+{
+  if (name[0] != '\0') {
+    if (*lgm == NULL) {
+      *lgm = MEM_callocN(sizeof(LightgroupMembership), __func__);
+    }
+    BLI_strncpy((*lgm)->name, name, sizeof((*lgm)->name));
+  }
+  else {
+    if (*lgm != NULL) {
+      MEM_freeN(*lgm);
+      *lgm = NULL;
+    }
+  }
+}
+
 /** \} */
diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index c00a403d5e9..833e6f882f1 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -260,6 +260,10 @@ static void object_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const in
   else {
     ob_dst->preview = nullptr;
   }
+
+  if (ob_src->lightgroup) {
+    ob_dst->lightgroup = (LightgroupMembership *)MEM_dupallocN(ob_src->lightgroup);
+  }
 }
 
 static void object_free_data(ID *id)
@@ -310,6 +314,8 @@ static void object_free_data(ID *id)
   }
 
   BKE_previewimg_free(&ob->preview);
+
+  MEM_SAFE_FREE(ob->lightgroup);
 }
 
 static void library_foreach_modifiersForeachIDLink(void *user_data,
@@ -584,6 +590,10 @@ static void object_blend_write(BlendWriter *writer, ID *id, const void *id_addre
   BLO_write_struct_list(writer, LinkData, &ob->pc_ids);
 
   BKE_previewimg_blend_write(writer, ob->preview);
+
+  if (ob->lightgroup) {
+    BLO_write_struct(writer, LightgroupMembership, ob->lightgroup);
+  }
 }
 
 /* XXX deprecated - old animation system */
@@ -800,6 +810,8 @@ static void object_blend_read_data(BlendDataReader *reader, ID *id)
 
   BLO_read_data_address(reader, &ob->preview);
   BKE_previewimg_blend_read(reader, ob->preview);
+
+  BLO_read_data_address(reader, &ob->lightgroup);
 }
 
 /* XXX deprecated - old animation system */
diff --git a/source/blender/blenkernel/intern/world.c b/source/blender/blenkernel/intern/world.c
index ac8b18f3395..cc3ee06f539 100644
--- a/source/blender/blenkernel/intern/world.c
+++ b/source/blender/blenkernel/intern/world.c
@@ -59,6 +59,8 @@ static void world_free_data(ID *id)
 
   BKE_icon_id_delete((struct ID *)wrld);
   BKE_previewimg_free(&wrld->preview);
+
+  MEM_SAFE_FREE(wrld->lightgroup);
 }
 
 static void world_init_data(ID *id)
@@ -107,6 +109,10 @@ static void world_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
   else {
     wrld_dst->preview = NULL;
   }
+
+  if (wrld_src->lightgroup) {
+    wrld_dst->lightgroup = (LightgroupMembership *)MEM_dupallocN(wrld_src->lightgroup);
+  }
 }
 
 static void world_foreach_id(ID *id, LibraryForeachIDData *data)
@@ -142,6 +148,10 @@ static void world_blend_write(BlendWriter *writer, ID *id, const void *id_addres
   }
 
   BKE_previewimg_blend_write(writer, wrld->preview);
+
+  if (wrld->lightgroup) {
+    BLO_write_struct(writer, LightgroupMembership, wrld->lightgroup);
+  }
 }
 
 static void world_blend_read_data(BlendDataReader *reader, ID *id)
@@ -153,6 +163,8 @@ static void world_blend_read_data(BlendDataReader *reader, ID *id)
   BLO_read_data_address(reader, &wrld->preview);
   BKE_previewimg_blend_read(reader, wrld->preview);
   BLI_listbase_clear(&wrld->gpumaterial);
+
+  BLO_read_data_address(reader, &wrld->lightgroup);
 }
 
 static void world_blend_read_lib(BlendLibReader *reader, ID *id)
diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 74797f91046..a4508cb5b6d 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -634,7 +634,7 @@ uiPopupMenu *UI_popup_menu_begin_ex(struct bContext *C,
  * Set the whole structure to work.
  */
 void UI_popup_menu_end(struct bContext *C, struct uiPopupMenu *pup);
-bool UI_popup_menu_end_or_cancel(struct bContext *C, struct uiPopupMenu *head);
+bool UI_popup_menu_end_or_cancel(struct bContext *C, struct uiPopupMenu *pup);
 struct uiLayout *UI_popup_menu_layout(uiPopupMenu *pup);
 
 void UI_popup_menu_reports(struct bContext *C, struct ReportList *reports) ATTR_NONNULL();
@@ -1595,13 +1595,15 @@ typedef enum {
 } eButLabelAlign;
 
 /* Return info for uiDefAutoButsRNA */
-typedef enum {
+typedef enum eAutoPropButsReturn {
   /* Returns when no buttons were added */
   UI_PROP_BUTS_NONE_ADDED = 1 << 0,
   /* Returned when any property failed the custom check callback (check_prop) */
   UI_PROP_BUTS_ANY_FAILED_CHECK = 1 << 1,
 } eAutoPropButsReturn;
 
+ENUM_OPERATORS(eAutoPropButsReturn, UI_PROP_BUTS_ANY_FAILED_CHECK);
+
 uiBut *uiDefAutoButR(uiBlock *block,
                      struct PointerRNA *ptr,
                      struct PropertyRNA *prop,
diff --git a/source/blender/editors/interface/CMakeLists.txt b/source/blender/editors/interface/CMakeLists.txt
index 100be2c10c9..a1ee5c38838 100644
--- a/source/blender/editors/interface/CMakeLists.txt
+++ b/source/blender/editors/interface/CMakeLists.txt
@@ -46,17 +46,17 @@ set(SRC
   interface_layout.c
   interface_ops.c
   interface_panel.c
-  interface_query.c
-  interface_region_color_picker.c
-  interface_region_hud.c
-  interface_region_menu_pie.c
-  interface_region_menu_popup.c
-  interface_region_popover.c
-  interface_region_popup.c
+  interface_query.cc
+  interface_region_color_picker.cc
+  interface_region_hud.cc
+  interface_region_menu_pie.cc
+  interface_region_menu_popup.cc
+  interface_region_popover.cc
+  interface_region_popup.cc
   interface_region_search.cc
   interface_region_tooltip.c
-  interface_regions.c
-  interface_style.c
+  interface_regions.cc
+  interface_style.cc
   interface_template_asset_view.cc
   interface_template_attribute_search.cc
   interface_template_list.cc
@@ -64,7 +64,7 @@ set(SRC
   interface_template_search_operator.c
   interface_templates.c
   interface_undo.c
-  interface_utils.c
+  interface_utils.cc
   interface_view.cc
   interface_widgets.c
   resources.c
diff --git a/source/blender/editors/interface/interface_intern.h b/source/blender/editors/interface/interface_intern.h
index a7a2409ef17..e619b14fb69 100644
--- a/source/blender/editors/interface/interface_intern.h
+++ b/source/blender/editors/interface/interface_intern.h
@@ -214,8 +214,8 @@ struct uiBut {
   BIFIconID icon;
   /** Copied from the #uiBlock.emboss */
   eUIEmbossType emboss;
-  /** direction in a pie menu, used for collision detection (RadialDirection) */
-  signed char pie_dir;
+  /** direction in a pie menu, used for collision detection. */
+  RadialDirection pie_dir;
   /** could be made into a single flag */
   bool changed;
   /** so buttons can support unit systems which are not RNA */
@@ -954,7 +954,7 @@ void ui_pie_menu_level_create(uiBlock *block,
                               const EnumPropertyItem *items,
                               int totitem,
                               wmOperatorCallContext context,
-                              int flag);
+                              wmOperatorCallContext flag);
 
 /* interface_region_popup.c */
 
diff --git a/source/blender/editors/interface/interface_query.c b/source/blender/editors/interface/interface_query.cc
index 4703367671d..2767a184619 100644
--- a/source/blender/editors/interface/interface_query.c
+++ b/source/blender/editors/interface/interface_query.cc
@@ -61,7 +61,7 @@ bool ui_but_is_toggle(const uiBut *but)
 bool ui_but_is_interactive(const uiBut *but, const bool labeledit)
 {
   /* NOTE: #UI_BTYPE_LABEL is included for highlights, this allows drags. */
-  if ((but->type == UI_BTYPE_LABEL) && but->dragpoin == NULL) {
+  if ((but->type == UI_BTYPE_LABEL) && but->dragpoin == nullptr) {
     return false;
   }
   if (ELEM(but->type, UI_BTYPE_ROUNDBOX, UI_BTYPE_SEPR, UI_BTYPE_SEPR_LINE, UI_BTYPE_LISTBOX)) {
@@ -119,12 +119,12 @@ bool ui_but_has_array_value(const uiBut *but)
                PROP_COORDS));
 }
 
-static wmOperatorType *g_ot_tool_set_by_id = NULL;
+static wmOperatorType *g_ot_tool_set_by_id = nullptr;
 bool UI_but_is_tool(const uiBut *but)
 {
   /* very evil! */
-  if (but->optype != NULL) {
-    if (g_ot_tool_set_by_id == NULL) {
+  if (but->optype != nullptr) {
+    if (g_ot_tool_set_by_id == nullptr) {
       g_ot_tool_set_by_id = WM_operatortype_find("WM_OT_tool_set_by_id", false);
     }
     if (but->optype == g_ot_tool_set_by_id) {
@@ -198,7 +198,7 @@ bool ui_but_contains_pt(const uiBut *but, float mx, float my)
 
 bool ui_but_contains_rect(const uiBut *but, const rctf *rect)
 {
-  return BLI_rctf_isect(&but->rect, rect, NULL);
+  return BLI_rctf_isect(&but->rect, rect, nullptr);
 }
 
 bool ui_but_contains_point_px(const uiBut *but, const ARegion *region, const int xy[2])
@@ -260,7 +260,7 @@ static uiBut *ui_but_find(const ARegion *region,
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_but_find_mouse_over_ex(const ARegion *region,
@@ -269,10 +269,10 @@ uiBut *ui_but_find_mouse_over_ex(const ARegion *region,
                                  const uiButFindPollFn find_poll,
                                  const void *find_custom_data)
 {
-  uiBut *butover = NULL;
+  uiBut *butover = nullptr;
 
   if (!ui_region_contains_point_px(region, xy)) {
-    return NULL;
+    return nullptr;
   }
   LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
     float mx = xy[0], my = xy[1];
@@ -310,20 +310,20 @@ uiBut *ui_but_find_mouse_over_ex(const ARegion *region,
 
 uiBut *ui_but_find_mouse_over(const ARegion *region, const wmEvent *event)
 {
-  return ui_but_find_mouse_over_ex(region, event->xy, event->modifier & KM_CTRL, NULL, NULL);
+  return ui_but_find_mouse_over_ex(region, event->xy, event->modifier & KM_CTRL, nullptr, nullptr);
 }
 
 uiBut *ui_but_find_rect_over(const struct ARegion *region, const rcti *rect_px)
 {
   if (!ui_region_contains_rect_px(region, rect_px)) {
-    return NULL;
+    return nullptr;
   }
 
   /* Currently no need to expose this at the moment. */
   const bool labeledit = true;
   rctf rect_px_fl;
   BLI_rctf_rcti_copy(&rect_px_fl, rect_px);
-  uiBut *butover = NULL;
+  uiBut *butover = nullptr;
 
   LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
     rctf rect_block;
@@ -343,7 +343,7 @@ uiBut *ui_but_find_rect_over(const struct ARegion *region, const rcti *rect_px)
     /* CLIP_EVENTS prevents the event from reaching other blocks */
     if (block->flag & UI_BLOCK_CLIP_EVENTS) {
       /* check if mouse is inside block */
-      if (BLI_rctf_isect(&block->rect, &rect_block, NULL)) {
+      if (BLI_rctf_isect(&block->rect, &rect_block, nullptr)) {
         break;
       }
     }
@@ -354,7 +354,7 @@ uiBut *ui_but_find_rect_over(const struct ARegion *region, const rcti *rect_px)
 uiBut *ui_list_find_mouse_over_ex(const ARegion *region, const int xy[2])
 {
   if (!ui_region_contains_point_px(region, xy)) {
-    return NULL;
+    return nullptr;
   }
   LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
     float mx = xy[0], my = xy[1];
@@ -366,14 +366,14 @@ uiBut *ui_list_find_mouse_over_ex(const ARegion *region, const int xy[2])
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_list_find_mouse_over(const ARegion *region, const wmEvent *event)
 {
-  if (event == NULL) {
+  if (event == nullptr) {
     /* If there is no info about the mouse, just act as if there is nothing underneath it. */
-    return NULL;
+    return nullptr;
   }
   return ui_list_find_mouse_over_ex(region, event->xy);
 }
@@ -382,10 +382,10 @@ uiList *UI_list_find_mouse_over(const ARegion *region, const wmEvent *event)
 {
   uiBut *list_but = ui_list_find_mouse_over(region, event);
   if (!list_but) {
-    return NULL;
+    return nullptr;
   }
 
-  return list_but->custom_data;
+  return static_cast<uiList *>(list_but->custom_data);
 }
 
 static bool ui_list_contains_row(const uiBut *listbox_but, const uiBut *listrow_but)
@@ -398,7 +398,7 @@ static bool ui_list_contains_row(const uiBut *listbox_but, const uiBut *listrow_
 
 static bool ui_but_is_listbox_with_row(const uiBut *but, const void *customdata)
 {
-  const uiBut *row_but = customdata;
+  const uiBut *row_but = static_cast<const uiBut *>(customdata);
   return (but->type == UI_BTYPE_LISTBOX) && ui_list_contains_row(but, row_but);
 }
 
@@ -414,7 +414,7 @@ static bool ui_but_is_listrow(const uiBut *but, const void *UNUSED(customdata))
 
 uiBut *ui_list_row_find_mouse_over(const ARegion *region, const int xy[2])
 {
-  return ui_but_find_mouse_over_ex(region, xy, false, ui_but_is_listrow, NULL);
+  return ui_but_find_mouse_over_ex(region, xy, false, ui_but_is_listrow, nullptr);
 }
 
 struct ListRowFindIndexData {
@@ -424,19 +424,18 @@ struct ListRowFindIndexData {
 
 static bool ui_but_is_listrow_at_index(const uiBut *but, const void *customdata)
 {
-  const struct ListRowFindIndexData *find_data = customdata;
+  const ListRowFindIndexData *find_data = static_cast<const ListRowFindIndexData *>(customdata);
 
-  return ui_but_is_listrow(but, NULL) && ui_list_contains_row(find_data->listbox, but) &&
+  return ui_but_is_listrow(but, nullptr) && ui_list_contains_row(find_data->listbox, but) &&
          (but->hardmax == find_data->index);
 }
 
 uiBut *ui_list_row_find_from_index(const ARegion *region, const int index, uiBut *listbox)
 {
   BLI_assert(listbox->type == UI_BTYPE_LISTBOX);
-  struct ListRowFindIndexData data = {
-      .index = index,
-      .listbox = listbox,
-  };
+  ListRowFindIndexData data = {};
+  data.index = index;
+  data.listbox = listbox;
   return ui_but_find(region, ui_but_is_listrow_at_index, &data);
 }
 
@@ -447,7 +446,7 @@ static bool ui_but_is_treerow(const uiBut *but, const void *UNUSED(customdata))
 
 uiBut *ui_tree_row_find_mouse_over(const ARegion *region, const int xy[2])
 {
-  return ui_but_find_mouse_over_ex(region, xy, false, ui_but_is_treerow, NULL);
+  return ui_but_find_mouse_over_ex(region, xy, false, ui_but_is_treerow, nullptr);
 }
 
 static bool ui_but_is_active_treerow(const uiBut *but, const void *customdata)
@@ -462,7 +461,7 @@ static bool ui_but_is_active_treerow(const uiBut *but, const void *customdata)
 
 uiBut *ui_tree_row_find_active(const ARegion *region)
 {
-  return ui_but_find(region, ui_but_is_active_treerow, NULL);
+  return ui_but_find(region, ui_but_is_active_treerow, nullptr);
 }
 
 /** \} */
@@ -479,7 +478,7 @@ uiBut *ui_but_prev(uiBut *but)
       return but;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_but_next(uiBut *but)
@@ -490,7 +489,7 @@ uiBut *ui_but_next(uiBut *but)
       return but;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_but_first(uiBlock *block)
@@ -500,21 +499,19 @@ uiBut *ui_but_first(uiBlock *block)
       return but;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_but_last(uiBlock *block)
 {
-  uiBut *but;
-
-  but = block->buttons.last;
+  uiBut *but = static_cast<uiBut *>(block->buttons.last);
   while (but) {
     if (ui_but_is_editable(but)) {
       return but;
     }
     but = but->prev;
   }
-  return NULL;
+  return nullptr;
 }
 
 bool ui_but_is_cursor_warp(const uiBut *but)
@@ -550,7 +547,7 @@ size_t ui_but_drawstr_len_without_sep_char(const uiBut *but)
 {
   if (but->flag & UI_BUT_HAS_SEP_CHAR) {
     const char *str_sep = strrchr(but->drawstr, UI_SEP_CHAR);
-    if (str_sep != NULL) {
+    if (str_sep != nullptr) {
       return (str_sep - but->drawstr);
     }
   }
@@ -565,12 +562,12 @@ size_t ui_but_drawstr_without_sep_char(const uiBut *but, char *str, size_t str_m
 
 size_t ui_but_tip_len_only_first_line(const uiBut *but)
 {
-  if (but->tip == NULL) {
+  if (but->tip == nullptr) {
     return 0;
   }
 
   const char *str_sep = strchr(but->tip, '\n');
-  if (str_sep != NULL) {
+  if (str_sep != nullptr) {
     return (str_sep - but->tip);
   }
   return strlen(but->tip);
@@ -590,7 +587,7 @@ uiBut *ui_block_active_but_get(const uiBlock *block)
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 bool ui_block_is_menu(const uiBlock *block)
@@ -622,12 +619,12 @@ static const uiBut *ui_but_next_non_separator(const uiBut *but)
       return but;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 bool UI_block_is_empty_ex(const uiBlock *block, const bool skip_title)
 {
-  const uiBut *but = block->buttons.first;
+  const uiBut *but = static_cast<const uiBut *>(block->buttons.first);
   if (skip_title) {
     /* Skip the first label, since popups often have a title,
      * we may want to consider the block empty in this case. */
@@ -636,7 +633,7 @@ bool UI_block_is_empty_ex(const uiBlock *block, const bool skip_title)
       but = but->next;
     }
   }
-  return (ui_but_next_non_separator(but) == NULL);
+  return (ui_but_next_non_separator(but) == nullptr);
 }
 
 bool UI_block_is_empty(const uiBlock *block)
@@ -647,7 +644,7 @@ bool UI_block_is_empty(const uiBlock *block)
 bool UI_block_can_add_separator(const uiBlock *block)
 {
   if (ui_block_is_menu(block) && !ui_block_is_pie_menu(block)) {
-    const uiBut *but = block->buttons.last;
+    const uiBut *but = static_cast<const uiBut *>(block->buttons.last);
     return (but && !ELEM(but->type, UI_BTYPE_SEPR_LINE, UI_BTYPE_SEPR));
   }
   return true;
@@ -662,7 +659,7 @@ bool UI_block_can_add_separator(const uiBlock *block)
 uiBlock *ui_block_find_mouse_over_ex(const ARegion *region, const int xy[2], bool only_clip)
 {
   if (!ui_region_contains_point_px(region, xy)) {
-    return NULL;
+    return nullptr;
   }
   LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
     if (only_clip) {
@@ -676,7 +673,7 @@ uiBlock *ui_block_find_mouse_over_ex(const ARegion *region, const int xy[2], boo
       return block;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 uiBlock *ui_block_find_mouse_over(const ARegion *region, const wmEvent *event, bool only_clip)
@@ -699,7 +696,7 @@ uiBut *ui_region_find_active_but(ARegion *region)
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_region_find_first_but_test_flag(ARegion *region, int flag_include, int flag_exclude)
@@ -712,7 +709,7 @@ uiBut *ui_region_find_first_but_test_flag(ARegion *region, int flag_include, int
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 /** \} */
@@ -752,7 +749,7 @@ bool ui_region_contains_rect_px(const ARegion *region, const rcti *rect_px)
 {
   rcti winrct;
   ui_region_winrct_get_no_margin(region, &winrct);
-  if (!BLI_rcti_isect(&winrct, rect_px, NULL)) {
+  if (!BLI_rcti_isect(&winrct, rect_px, nullptr)) {
     return false;
   }
 
@@ -761,7 +758,7 @@ bool ui_region_contains_rect_px(const ARegion *region, const rcti *rect_px)
     const View2D *v2d = &region->v2d;
     rcti rect_region;
     ui_window_to_region_rcti(region, &rect_region, rect_px);
-    if (!BLI_rcti_isect(&v2d->mask, &rect_region, NULL) ||
+    if (!BLI_rcti_isect(&v2d->mask, &rect_region, nullptr) ||
         UI_view2d_rect_in_scrollers(region, &region->v2d, rect_px)) {
       return false;
     }
@@ -787,7 +784,7 @@ ARegion *ui_screen_region_find_mouse_over_ex(bScreen *screen, const int xy[2])
       return region;
     }
   }
-  return NULL;
+  return nullptr;
 }
 
 ARegion *ui_screen_region_find_mouse_over(bScreen *screen, const wmEvent *event)
@@ -803,7 +800,7 @@ ARegion *ui_screen_region_find_mouse_over(bScreen *screen, const wmEvent *event)
 
 void ui_interface_tag_script_reload_queries(void)
 {
-  g_ot_tool_set_by_id = NULL;
+  g_ot_tool_set_by_id = nullptr;
 }
 
 /** \} */
diff --git a/source/blender/editors/interface/interface_region_color_picker.c b/source/blender/editors/interface/interface_region_color_picker.cc
index 9fb6f538191..ab0a6039cdc 100644
--- a/source/blender/editors/interface/interface_region_color_picker.c
+++ b/source/blender/editors/interface/interface_region_color_picker.cc
@@ -7,9 +7,9 @@
  * Color Picker Region & Color Utils
  */
 
-#include <stdarg.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdarg>
+#include <cstdlib>
+#include <cstring>
 
 #include "MEM_guardedalloc.h"
 
@@ -168,7 +168,7 @@ static void ui_color_picker_update_hsv(ColorPicker *cpicker,
 void ui_but_hsv_set(uiBut *but)
 {
   float rgb_perceptual[3];
-  ColorPicker *cpicker = but->custom_data;
+  ColorPicker *cpicker = static_cast<ColorPicker *>(but->custom_data);
   float *hsv_perceptual = cpicker->hsv_perceptual;
 
   ui_color_picker_hsv_to_rgb(hsv_perceptual, rgb_perceptual);
@@ -255,7 +255,8 @@ static void ui_colorpicker_rgba_update_cb(bContext *UNUSED(C), void *bt1, void *
 
   if (prop) {
     RNA_property_float_get_array(&ptr, prop, rgb_scene_linear);
-    ui_update_color_picker_buts_rgb(but, but->block, but->custom_data, rgb_scene_linear);
+    ui_update_color_picker_buts_rgb(
+        but, but->block, static_cast<ColorPicker *>(but->custom_data), rgb_scene_linear);
   }
 
   if (popup) {
@@ -268,7 +269,7 @@ static void ui_colorpicker_hsv_update_cb(bContext *UNUSED(C), void *bt1, void *U
   uiBut *but = (uiBut *)bt1;
   uiPopupBlockHandle *popup = but->block->handle;
   float rgb_scene_linear[3];
-  ColorPicker *cpicker = but->custom_data;
+  ColorPicker *cpicker = static_cast<ColorPicker *>(but->custom_data);
 
   ui_color_picker_hsv_to_rgb(cpicker->hsv_scene_linear, rgb_scene_linear);
   ui_update_color_picker_buts_rgb(but, but->block, cpicker, rgb_scene_linear);
@@ -282,7 +283,7 @@ static void ui_colorpicker_hex_rna_cb(bContext *UNUSED(C), void *bt1, void *hexc
 {
   uiBut *but = (uiBut *)bt1;
   uiPopupBlockHandle *popup = but->block->handle;
-  ColorPicker *cpicker = but->custom_data;
+  ColorPicker *cpicker = static_cast<ColorPicker *>(but->custom_data);
   char *hexcol = (char *)hexcl;
   float rgb[3];
 
@@ -307,7 +308,7 @@ static void ui_popup_close_cb(bContext *UNUSED(C), void *bt1, void *UNUSED(arg))
   uiPopupBlockHandle *popup = but->block->handle;
 
   if (popup) {
-    ColorPicker *cpicker = but->custom_data;
+    ColorPicker *cpicker = static_cast<ColorPicker *>(but->custom_data);
     BLI_assert(cpicker->is_init);
     popup->menuretval = (equals_v3v3(cpicker->hsv_perceptual, cpicker->hsv_perceptual_init) ?
                              UI_RETURN_CANCEL :
@@ -315,7 +316,7 @@ static void ui_popup_close_cb(bContext *UNUSED(C), void *bt1, void *UNUSED(arg))
   }
 }
 
-static void ui_colorpicker_hide_reveal(uiBlock *block, enum ePickerType colormode)
+static void ui_colorpicker_hide_reveal(uiBlock *block, ePickerType colormode)
 {
   /* tag buttons */
   LISTBASE_FOREACH (uiBut *, bt, &block->buttons) {
@@ -337,9 +338,9 @@ static void ui_colorpicker_hide_reveal(uiBlock *block, enum ePickerType colormod
 
 static void ui_colorpicker_create_mode_cb(bContext *UNUSED(C), void *bt1, void *UNUSED(arg))
 {
-  uiBut *bt = bt1;
+  uiBut *bt = static_cast<uiBut *>(bt1);
   const short colormode = ui_but_value_get(bt);
-  ui_colorpicker_hide_reveal(bt->block, colormode);
+  ui_colorpicker_hide_reveal(bt->block, (ePickerType)colormode);
 }
 
 #define PICKER_H (7.5f * U.widget_unit)
@@ -374,7 +375,7 @@ static void ui_colorpicker_circle(uiBlock *block,
                       0.0,
                       0,
                       TIP_("Color"));
-  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
 
   /* value */
@@ -396,7 +397,7 @@ static void ui_colorpicker_circle(uiBlock *block,
                                              0,
                                              "Lightness");
     hsv_but->gradient_type = UI_GRAD_L_ALT;
-    UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, NULL);
+    UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, nullptr);
   }
   else {
     hsv_but = (uiButHSVCube *)uiDefButR_prop(block,
@@ -416,7 +417,7 @@ static void ui_colorpicker_circle(uiBlock *block,
                                              0,
                                              TIP_("Value"));
     hsv_but->gradient_type = UI_GRAD_V_ALT;
-    UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, NULL);
+    UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, nullptr);
   }
   hsv_but->but.custom_data = cpicker;
 }
@@ -449,7 +450,7 @@ static void ui_colorpicker_square(uiBlock *block,
                                            0,
                                            TIP_("Color"));
   hsv_but->gradient_type = type;
-  UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, NULL);
+  UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, nullptr);
   hsv_but->but.custom_data = cpicker;
 
   /* value */
@@ -469,8 +470,8 @@ static void ui_colorpicker_square(uiBlock *block,
                                            0,
                                            0,
                                            TIP_("Value"));
-  hsv_but->gradient_type = type + 3;
-  UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, NULL);
+  hsv_but->gradient_type = (eButGradientType)(type + 3);
+  UI_but_func_set(&hsv_but->but, ui_colorpicker_rgba_update_cb, &hsv_but->but, nullptr);
   hsv_but->but.custom_data = cpicker;
 }
 
@@ -547,7 +548,7 @@ static void ui_block_colorpicker(uiBlock *block,
                  "");
   UI_but_flag_disable(bt, UI_BUT_UNDO);
   UI_but_drawflag_disable(bt, UI_BUT_TEXT_LEFT);
-  UI_but_func_set(bt, ui_colorpicker_create_mode_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_create_mode_cb, bt, nullptr);
   bt->custom_data = cpicker;
   bt = uiDefButC(block,
                  UI_BTYPE_ROW,
@@ -565,7 +566,7 @@ static void ui_block_colorpicker(uiBlock *block,
                  "");
   UI_but_flag_disable(bt, UI_BUT_UNDO);
   UI_but_drawflag_disable(bt, UI_BUT_TEXT_LEFT);
-  UI_but_func_set(bt, ui_colorpicker_create_mode_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_create_mode_cb, bt, nullptr);
   bt->custom_data = cpicker;
   bt = uiDefButC(block,
                  UI_BTYPE_ROW,
@@ -583,7 +584,7 @@ static void ui_block_colorpicker(uiBlock *block,
                  "");
   UI_but_flag_disable(bt, UI_BUT_UNDO);
   UI_but_drawflag_disable(bt, UI_BUT_TEXT_LEFT);
-  UI_but_func_set(bt, ui_colorpicker_create_mode_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_create_mode_cb, bt, nullptr);
   bt->custom_data = cpicker;
   UI_block_align_end(block);
 
@@ -598,10 +599,10 @@ static void ui_block_colorpicker(uiBlock *block,
                        yco,
                        UI_UNIT_X,
                        UI_UNIT_Y,
-                       NULL);
+                       nullptr);
     UI_but_flag_disable(bt, UI_BUT_UNDO);
     UI_but_drawflag_disable(bt, UI_BUT_ICON_LEFT);
-    UI_but_func_set(bt, ui_popup_close_cb, bt, NULL);
+    UI_but_func_set(bt, ui_popup_close_cb, bt, nullptr);
     bt->custom_data = cpicker;
   }
 
@@ -625,7 +626,7 @@ static void ui_block_colorpicker(uiBlock *block,
                       0,
                       3,
                       TIP_("Red"));
-  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
   bt = uiDefButR_prop(block,
                       UI_BTYPE_NUM_SLIDER,
@@ -643,7 +644,7 @@ static void ui_block_colorpicker(uiBlock *block,
                       0,
                       3,
                       TIP_("Green"));
-  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
   bt = uiDefButR_prop(block,
                       UI_BTYPE_NUM_SLIDER,
@@ -661,7 +662,7 @@ static void ui_block_colorpicker(uiBlock *block,
                       0,
                       3,
                       TIP_("Blue"));
-  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
 
   /* Could use:
@@ -686,7 +687,7 @@ static void ui_block_colorpicker(uiBlock *block,
                  3,
                  TIP_("Hue"));
   UI_but_flag_disable(bt, UI_BUT_UNDO);
-  UI_but_func_set(bt, ui_colorpicker_hsv_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_hsv_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
   bt = uiDefButF(block,
                  UI_BTYPE_NUM_SLIDER,
@@ -703,7 +704,7 @@ static void ui_block_colorpicker(uiBlock *block,
                  3,
                  TIP_("Saturation"));
   UI_but_flag_disable(bt, UI_BUT_UNDO);
-  UI_but_func_set(bt, ui_colorpicker_hsv_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_hsv_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
   if (U.color_picker_type == USER_CP_CIRCLE_HSL) {
     bt = uiDefButF(block,
@@ -740,7 +741,7 @@ static void ui_block_colorpicker(uiBlock *block,
   UI_but_flag_disable(bt, UI_BUT_UNDO);
 
   bt->hardmax = hardmax; /* not common but rgb  may be over 1.0 */
-  UI_but_func_set(bt, ui_colorpicker_hsv_update_cb, bt, NULL);
+  UI_but_func_set(bt, ui_colorpicker_hsv_update_cb, bt, nullptr);
   bt->custom_data = cpicker;
 
   UI_block_align_end(block);
@@ -762,7 +763,7 @@ static void ui_block_colorpicker(uiBlock *block,
                         0,
                         3,
                         TIP_("Alpha"));
-    UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, NULL);
+    UI_but_func_set(bt, ui_colorpicker_rgba_update_cb, bt, nullptr);
     bt->custom_data = cpicker;
   }
   else {
@@ -809,14 +810,14 @@ static void ui_block_colorpicker(uiBlock *block,
            yco - UI_UNIT_Y,
            butwidth,
            UI_UNIT_Y,
-           NULL,
+           nullptr,
            0.0,
            0.0,
            0,
            0,
            "");
 
-  ui_colorpicker_hide_reveal(block, colormode);
+  ui_colorpicker_hide_reveal(block, (ePickerType)colormode);
 }
 
 static int ui_colorpicker_small_wheel_cb(const bContext *UNUSED(C),
@@ -834,9 +835,9 @@ static int ui_colorpicker_small_wheel_cb(const bContext *UNUSED(C),
 
   if (add != 0.0f) {
     LISTBASE_FOREACH (uiBut *, but, &block->buttons) {
-      if (but->type == UI_BTYPE_HSVCUBE && but->active == NULL) {
+      if (but->type == UI_BTYPE_HSVCUBE && but->active == nullptr) {
         uiPopupBlockHandle *popup = block->handle;
-        ColorPicker *cpicker = but->custom_data;
+        ColorPicker *cpicker = static_cast<ColorPicker *>(but->custom_data);
         float *hsv_perceptual = cpicker->hsv_perceptual;
 
         float rgb_perceptual[3];
@@ -865,7 +866,7 @@ static int ui_colorpicker_small_wheel_cb(const bContext *UNUSED(C),
 
 uiBlock *ui_block_func_COLOR(bContext *C, uiPopupBlockHandle *handle, void *arg_but)
 {
-  uiBut *but = arg_but;
+  uiBut *but = static_cast<uiBut *>(arg_but);
   uiBlock *block;
   bool show_picker = true;
 
@@ -901,7 +902,7 @@ uiBlock *ui_block_func_COLOR(bContext *C, uiPopupBlockHandle *handle, void *arg_
 
 ColorPicker *ui_block_colorpicker_create(struct uiBlock *block)
 {
-  ColorPicker *cpicker = MEM_callocN(sizeof(ColorPicker), "color_picker");
+  ColorPicker *cpicker = MEM_cnew<ColorPicker>(__func__);
   BLI_addhead(&block->color_pickers.list, cpicker);
 
   return cpicker;
diff --git a/source/blender/editors/interface/interface_region_hud.c b/source/blender/editors/interface/interface_region_hud.cc
index 4d72cd5382c..d6166694a4a 100644
--- a/source/blender/editors/interface/interface_region_hud.c
+++ b/source/blender/editors/interface/interface_region_hud.cc
@@ -7,7 +7,7 @@
  * Floating Persistent Region
  */
 
-#include <string.h>
+#include <cstring>
 
 #include "MEM_guardedalloc.h"
 
@@ -49,7 +49,7 @@ struct HudRegionData {
 static bool last_redo_poll(const bContext *C, short region_type)
 {
   wmOperator *op = WM_operator_last_redo(C);
-  if (op == NULL) {
+  if (op == nullptr) {
     return false;
   }
 
@@ -60,7 +60,8 @@ static bool last_redo_poll(const bContext *C, short region_type)
      * wrong context.
      */
     ScrArea *area = CTX_wm_area(C);
-    ARegion *region_op = (region_type != -1) ? BKE_area_find_region_type(area, region_type) : NULL;
+    ARegion *region_op = (region_type != -1) ? BKE_area_find_region_type(area, region_type) :
+                                               nullptr;
     ARegion *region_prev = CTX_wm_region(C);
     CTX_wm_region_set((bContext *)C, region_op);
 
@@ -90,9 +91,9 @@ static bool hud_panel_operator_redo_poll(const bContext *C, PanelType *UNUSED(pt
 {
   ScrArea *area = CTX_wm_area(C);
   ARegion *region = BKE_area_find_region_type(area, RGN_TYPE_HUD);
-  if (region != NULL) {
-    struct HudRegionData *hrd = region->regiondata;
-    if (hrd != NULL) {
+  if (region != nullptr) {
+    HudRegionData *hrd = static_cast<HudRegionData *>(region->regiondata);
+    if (hrd != nullptr) {
       return last_redo_poll(C, hrd->regionid);
     }
   }
@@ -108,7 +109,7 @@ static void hud_panel_operator_redo_draw_header(const bContext *C, Panel *panel)
 static void hud_panel_operator_redo_draw(const bContext *C, Panel *panel)
 {
   wmOperator *op = WM_operator_last_redo(C);
-  if (op == NULL) {
+  if (op == nullptr) {
     return;
   }
   if (!WM_operator_check_ui_enabled(C, op->type->name)) {
@@ -120,9 +121,7 @@ static void hud_panel_operator_redo_draw(const bContext *C, Panel *panel)
 
 static void hud_panels_register(ARegionType *art, int space_type, int region_type)
 {
-  PanelType *pt;
-
-  pt = MEM_callocN(sizeof(PanelType), __func__);
+  PanelType *pt = MEM_cnew<PanelType>(__func__);
   strcpy(pt->idname, "OPERATOR_PT_redo");
   strcpy(pt->label, N_("Redo"));
   strcpy(pt->translation_context, BLT_I18NCONTEXT_DEFAULT_BPYRNA);
@@ -155,8 +154,8 @@ static void hud_region_free(ARegion *region)
 
 static void hud_region_layout(const bContext *C, ARegion *region)
 {
-  struct HudRegionData *hrd = region->regiondata;
-  if (hrd == NULL || !last_redo_poll(C, hrd->regionid)) {
+  HudRegionData *hrd = static_cast<HudRegionData *>(region->regiondata);
+  if (hrd == nullptr || !last_redo_poll(C, hrd->regionid)) {
     ED_region_tag_redraw(region);
     hud_region_hide(region);
     return;
@@ -205,19 +204,17 @@ static void hud_region_draw(const bContext *C, ARegion *region)
   GPU_clear_color(0.0f, 0.0f, 0.0f, 0.0f);
 
   if ((region->flag & RGN_FLAG_HIDDEN) == 0) {
-    ui_draw_menu_back(NULL,
-                      NULL,
-                      &(rcti){
-                          .xmax = region->winx,
-                          .ymax = region->winy,
-                      });
+    rcti reset_rect = {};
+    reset_rect.xmax = region->winx;
+    reset_rect.ymax = region->winy;
+    ui_draw_menu_back(nullptr, nullptr, &reset_rect);
     ED_region_panels_draw(C, region);
   }
 }
 
 ARegionType *ED_area_type_hud(int space_type)
 {
-  ARegionType *art = MEM_callocN(sizeof(ARegionType), __func__);
+  ARegionType *art = MEM_cnew<ARegionType>(__func__);
   art->regionid = RGN_TYPE_HUD;
   art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D;
   art->layout = hud_region_layout;
@@ -238,7 +235,7 @@ ARegionType *ED_area_type_hud(int space_type)
 
 static ARegion *hud_region_add(ScrArea *area)
 {
-  ARegion *region = MEM_callocN(sizeof(ARegion), "area region");
+  ARegion *region = MEM_cnew<ARegion>(__func__);
   ARegion *region_win = BKE_area_find_region_type(area, RGN_TYPE_WINDOW);
   if (region_win) {
     BLI_insertlinkbefore(&area->regionbase, region_win, region);
@@ -288,7 +285,7 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *area)
   ED_area_type_hud_clear(wm, area);
 
   ARegionType *art = BKE_regiontype_from_id(area->type, RGN_TYPE_HUD);
-  if (art == NULL) {
+  if (art == nullptr) {
     return;
   }
 
@@ -301,9 +298,9 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *area)
   }
 
   bool init = false;
-  const bool was_hidden = region == NULL || region->visible == false;
+  const bool was_hidden = region == nullptr || region->visible == false;
   ARegion *region_op = CTX_wm_region(C);
-  BLI_assert((region_op == NULL) || (region_op->regiontype != RGN_TYPE_HUD));
+  BLI_assert((region_op == nullptr) || (region_op->regiontype != RGN_TYPE_HUD));
   if (!last_redo_poll(C, region_op ? region_op->regiontype : -1)) {
     if (region) {
       ED_region_tag_redraw(region);
@@ -312,7 +309,7 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *area)
     return;
   }
 
-  if (region == NULL) {
+  if (region == nullptr) {
     init = true;
     region = hud_region_add(area);
     region->type = art;
@@ -332,9 +329,9 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *area)
   }
 
   {
-    struct HudRegionData *hrd = region->regiondata;
-    if (hrd == NULL) {
-      hrd = MEM_callocN(sizeof(*hrd), __func__);
+    HudRegionData *hrd = static_cast<HudRegionData *>(region->regiondata);
+    if (hrd == nullptr) {
+      hrd = MEM_cnew<HudRegionData>(__func__);
       region->regiondata = hrd;
     }
     if (region_op) {
@@ -355,10 +352,10 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *area)
   ED_region_tag_redraw(region);
 
   /* Reset zoom level (not well supported). */
-  region->v2d.cur = region->v2d.tot = (rctf){
-      .xmax = region->winx,
-      .ymax = region->winy,
-  };
+  rctf reset_rect = {};
+  reset_rect.xmax = region->winx;
+  reset_rect.ymax = region->winy;
+  region->v2d.cur = region->v2d.tot = reset_rect;
   region->v2d.minzoom = 1.0f;
   region->v2d.maxzoom = 1.0f;
 
@@ -373,10 +370,7 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *area)
     if (was_hidden) {
       region->winx = region->v2d.winx;
       region->winy = region->v2d.winy;
-      region->v2d.cur = region->v2d.tot = (rctf){
-          .xmax = region->winx,
-          .ymax = region->winy,
-      };
+      region->v2d.cur = region->v2d.tot = reset_rect;
     }
     CTX_wm_region_set((bContext *)C, region_prev);
   }
diff --git a/source/blender/editors/interface/interface_region_menu_pie.c b/source/blender/editors/interface/interface_region_menu_pie.cc
index 74e128f3098..586aeef44fd 100644
--- a/source/blender/editors/interface/interface_region_menu_pie.c
+++ b/source/blender/editors/interface/interface_region_menu_pie.cc
@@ -7,9 +7,9 @@
  * Pie Menu Region
  */
 
-#include <stdarg.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdarg>
+#include <cstdlib>
+#include <cstring>
 
 #include "MEM_guardedalloc.h"
 
@@ -51,7 +51,7 @@ struct uiPieMenu {
 static uiBlock *ui_block_func_PIE(bContext *UNUSED(C), uiPopupBlockHandle *handle, void *arg_pie)
 {
   uiBlock *block;
-  uiPieMenu *pie = arg_pie;
+  uiPieMenu *pie = static_cast<uiPieMenu *>(arg_pie);
   int minwidth, width, height;
 
   minwidth = UI_MENU_WIDTH_MIN;
@@ -89,14 +89,13 @@ static float ui_pie_menu_title_width(const char *name, int icon)
 uiPieMenu *UI_pie_menu_begin(struct bContext *C, const char *title, int icon, const wmEvent *event)
 {
   const uiStyle *style = UI_style_get_dpi();
-  uiPieMenu *pie;
   short event_type;
 
   wmWindow *win = CTX_wm_window(C);
 
-  pie = MEM_callocN(sizeof(*pie), "pie menu");
+  uiPieMenu *pie = MEM_cnew<uiPieMenu>(__func__);
 
-  pie->block_radial = UI_block_begin(C, NULL, __func__, UI_EMBOSS);
+  pie->block_radial = UI_block_begin(C, nullptr, __func__, UI_EMBOSS);
   /* may be useful later to allow spawning pies
    * from old positions */
   /* pie->block_radial->flag |= UI_BLOCK_POPUP_MEMORY; */
@@ -153,7 +152,7 @@ uiPieMenu *UI_pie_menu_begin(struct bContext *C, const char *title, int icon, co
                              0,
                              w,
                              UI_UNIT_Y,
-                             NULL,
+                             nullptr,
                              0.0,
                              0.0,
                              0,
@@ -170,7 +169,7 @@ uiPieMenu *UI_pie_menu_begin(struct bContext *C, const char *title, int icon, co
                      0,
                      w,
                      UI_UNIT_Y,
-                     NULL,
+                     nullptr,
                      0.0,
                      0.0,
                      0,
@@ -191,7 +190,7 @@ void UI_pie_menu_end(bContext *C, uiPieMenu *pie)
   wmWindow *window = CTX_wm_window(C);
   uiPopupBlockHandle *menu;
 
-  menu = ui_popup_block_create(C, NULL, NULL, NULL, ui_block_func_PIE, pie, NULL);
+  menu = ui_popup_block_create(C, nullptr, nullptr, nullptr, ui_block_func_PIE, pie, nullptr);
   menu->popup = true;
   menu->towardstime = PIL_check_seconds_timer();
 
@@ -212,7 +211,7 @@ int UI_pie_menu_invoke(struct bContext *C, const char *idname, const wmEvent *ev
   uiLayout *layout;
   MenuType *mt = WM_menutype_find(idname, true);
 
-  if (mt == NULL) {
+  if (mt == nullptr) {
     printf("%s: named menu \"%s\" not found\n", __func__, idname);
     return OPERATOR_CANCELLED;
   }
@@ -263,7 +262,7 @@ int UI_pie_menu_invoke_from_rna_enum(struct bContext *C,
   uiPieMenu *pie;
   uiLayout *layout;
 
-  RNA_pointer_create(NULL, &RNA_Context, C, &ctx_ptr);
+  RNA_pointer_create(nullptr, &RNA_Context, C, &ctx_ptr);
 
   if (!RNA_path_resolve(&ctx_ptr, path, &r_ptr, &r_prop)) {
     return OPERATOR_CANCELLED;
@@ -280,7 +279,7 @@ int UI_pie_menu_invoke_from_rna_enum(struct bContext *C,
   layout = UI_pie_menu_layout(pie);
 
   layout = uiLayoutRadial(layout);
-  uiItemFullR(layout, &r_ptr, r_prop, RNA_NO_INDEX, 0, UI_ITEM_R_EXPAND, NULL, 0);
+  uiItemFullR(layout, &r_ptr, r_prop, RNA_NO_INDEX, 0, UI_ITEM_R_EXPAND, nullptr, 0);
 
   UI_pie_menu_end(C, pie);
 
@@ -304,7 +303,7 @@ int UI_pie_menu_invoke_from_rna_enum(struct bContext *C,
  * - Julian (Feb 2016)
  * \{ */
 
-typedef struct PieMenuLevelData {
+ struct PieMenuLevelData {
   char title[UI_MAX_NAME_STR]; /* parent pie title, copied for level */
   int icon;                    /* parent pie icon, copied for level */
   int totitem;                 /* total count of *remaining* items */
@@ -314,7 +313,7 @@ typedef struct PieMenuLevelData {
   const char *propname;
   IDProperty *properties;
   wmOperatorCallContext context, flag;
-} PieMenuLevelData;
+} ;
 
 /**
  * Invokes a new pie menu for a new level.
@@ -362,17 +361,17 @@ void ui_pie_menu_level_create(uiBlock *block,
                               const EnumPropertyItem *items,
                               int totitem,
                               wmOperatorCallContext context,
-                              int flag)
+                              wmOperatorCallContext flag)
 {
   const int totitem_parent = PIE_MAX_ITEMS - 1;
   const int totitem_remain = totitem - totitem_parent;
   const size_t array_size = sizeof(EnumPropertyItem) * totitem_remain;
 
   /* used as but->func_argN so freeing is handled elsewhere */
-  EnumPropertyItem *remaining = MEM_mallocN(array_size + sizeof(EnumPropertyItem),
-                                            "pie_level_item_array");
+  EnumPropertyItem *remaining = static_cast<EnumPropertyItem *>(
+      MEM_mallocN(array_size + sizeof(EnumPropertyItem), "pie_level_item_array"));
   memcpy(remaining, items + totitem_parent, array_size);
-  /* A NULL terminating sentinel element is required. */
+  /* A nullptr terminating sentinel element is required. */
   memset(&remaining[totitem_remain], 0, sizeof(EnumPropertyItem));
 
   /* yuk, static... issue is we can't reliably free this without doing dangerous changes */
@@ -395,7 +394,7 @@ void ui_pie_menu_level_create(uiBlock *block,
                                 0,
                                 UI_UNIT_X * 3,
                                 UI_UNIT_Y,
-                                NULL,
+                                nullptr,
                                 0.0f,
                                 0.0f,
                                 0.0f,
diff --git a/source/blender/editors/interface/interface_region_menu_popup.c b/source/blender/editors/interface/interface_region_menu_popup.cc
index 7d8f4315710..e843a275d08 100644
--- a/source/blender/editors/interface/interface_region_menu_popup.c
+++ b/source/blender/editors/interface/interface_region_menu_popup.cc
@@ -7,9 +7,9 @@
  * PopUp Menu Region
  */
 
-#include <stdarg.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdarg>
+#include <cstdlib>
+#include <cstring>
 
 #include "MEM_guardedalloc.h"
 
@@ -50,7 +50,7 @@ bool ui_but_menu_step_poll(const uiBut *but)
   BLI_assert(but->type == UI_BTYPE_MENU);
 
   /* currently only RNA buttons */
-  return ((but->menu_step_func != NULL) ||
+  return ((but->menu_step_func != nullptr) ||
           (but->rnaprop && RNA_property_type(but->rnaprop) == PROP_ENUM));
 }
 
@@ -58,12 +58,16 @@ int ui_but_menu_step(uiBut *but, int direction)
 {
   if (ui_but_menu_step_poll(but)) {
     if (but->menu_step_func) {
-      return but->menu_step_func(but->block->evil_C, direction, but->poin);
+      return but->menu_step_func(
+          static_cast<bContext *>(but->block->evil_C), direction, but->poin);
     }
 
     const int curval = RNA_property_enum_get(&but->rnapoin, but->rnaprop);
-    return RNA_property_enum_step(
-        but->block->evil_C, &but->rnapoin, but->rnaprop, curval, direction);
+    return RNA_property_enum_step(static_cast<bContext *>(but->block->evil_C),
+                                  &but->rnapoin,
+                                  but->rnaprop,
+                                  curval,
+                                  direction);
   }
 
   printf("%s: cannot cycle button '%s'\n", __func__, but->str);
@@ -85,7 +89,7 @@ static uint ui_popup_string_hash(const char *str, const bool use_sep)
 {
   /* sometimes button contains hotkey, sometimes not, strip for proper compare */
   int hash;
-  const char *delimit = use_sep ? strrchr(str, UI_SEP_CHAR) : NULL;
+  const char *delimit = use_sep ? strrchr(str, UI_SEP_CHAR) : nullptr;
 
   if (delimit) {
     hash = BLI_ghashutil_strhash_n(str, delimit - str);
@@ -102,7 +106,7 @@ uint ui_popup_menu_hash(const char *str)
   return BLI_ghashutil_strhash(str);
 }
 
-/* but == NULL read, otherwise set */
+/* but == nullptr read, otherwise set */
 static uiBut *ui_popup_menu_memory__internal(uiBlock *block, uiBut *but)
 {
   static uint mem[256];
@@ -114,13 +118,13 @@ static uiBut *ui_popup_menu_memory__internal(uiBlock *block, uiBut *but)
   if (first) {
     /* init */
     memset(mem, -1, sizeof(mem));
-    first = 0;
+    first = false;
   }
 
   if (but) {
     /* set */
     mem[hash_mod] = ui_popup_string_hash(but->str, but->flag & UI_BUT_HAS_SEP_CHAR);
-    return NULL;
+    return nullptr;
   }
 
   /* get */
@@ -131,12 +135,12 @@ static uiBut *ui_popup_menu_memory__internal(uiBlock *block, uiBut *but)
     }
   }
 
-  return NULL;
+  return nullptr;
 }
 
 uiBut *ui_popup_menu_memory_get(uiBlock *block)
 {
-  return ui_popup_menu_memory__internal(block, NULL);
+  return ui_popup_menu_memory__internal(block, nullptr);
 }
 
 void ui_popup_menu_memory_set(uiBlock *block, uiBut *but)
@@ -166,7 +170,7 @@ struct uiPopupMenu {
 static uiBlock *ui_block_func_POPUP(bContext *C, uiPopupBlockHandle *handle, void *arg_pup)
 {
   uiBlock *block;
-  uiPopupMenu *pup = arg_pup;
+  uiPopupMenu *pup = static_cast<uiPopupMenu *>(arg_pup);
   int minwidth, width, height;
   char direction;
   bool flip;
@@ -174,7 +178,7 @@ static uiBlock *ui_block_func_POPUP(bContext *C, uiPopupBlockHandle *handle, voi
   if (pup->menu_func) {
     pup->block->handle = handle;
     pup->menu_func(C, pup->layout, pup->menu_arg);
-    pup->block->handle = NULL;
+    pup->block->handle = nullptr;
   }
 
   /* Find block minimum width. */
@@ -229,7 +233,7 @@ static uiBlock *ui_block_func_POPUP(bContext *C, uiPopupBlockHandle *handle, voi
   if (pup->popup) {
     int offset[2];
 
-    uiBut *but_activate = NULL;
+    uiBut *but_activate = nullptr;
     UI_block_flag_enable(block, UI_BLOCK_LOOP | UI_BLOCK_NUMSELECT);
     UI_block_theme_style_set(block, UI_BLOCK_THEME_STYLE_POPUP);
     UI_block_direction_set(block, direction);
@@ -309,10 +313,9 @@ uiPopupBlockHandle *ui_popup_menu_create(
   wmWindow *window = CTX_wm_window(C);
   const uiStyle *style = UI_style_get_dpi();
   uiPopupBlockHandle *handle;
-  uiPopupMenu *pup;
 
-  pup = MEM_callocN(sizeof(uiPopupMenu), __func__);
-  pup->block = UI_block_begin(C, NULL, __func__, UI_EMBOSS_PULLDOWN);
+  uiPopupMenu *pup = MEM_cnew<uiPopupMenu>(__func__);
+  pup->block = UI_block_begin(C, nullptr, __func__, UI_EMBOSS_PULLDOWN);
   pup->block->flag |= UI_BLOCK_NUMSELECT; /* default menus to numselect */
   pup->layout = UI_block_layout(
       pup->block, UI_LAYOUT_VERTICAL, UI_LAYOUT_MENU, 0, 0, 200, 0, UI_MENU_PADDING, style);
@@ -348,7 +351,7 @@ uiPopupBlockHandle *ui_popup_menu_create(
   pup->menu_func = menu_func;
   pup->menu_arg = arg;
 
-  handle = ui_popup_block_create(C, butregion, but, NULL, ui_block_func_POPUP, pup, NULL);
+  handle = ui_popup_block_create(C, butregion, but, nullptr, ui_block_func_POPUP, pup, nullptr);
 
   if (!but) {
     handle->popup = true;
@@ -374,10 +377,10 @@ uiPopupMenu *UI_popup_menu_begin_ex(bContext *C,
                                     int icon)
 {
   const uiStyle *style = UI_style_get_dpi();
-  uiPopupMenu *pup = MEM_callocN(sizeof(uiPopupMenu), "popup menu");
+  uiPopupMenu *pup = MEM_cnew<uiPopupMenu>(__func__);
   uiBut *but;
 
-  pup->block = UI_block_begin(C, NULL, block_name, UI_EMBOSS_PULLDOWN);
+  pup->block = UI_block_begin(C, nullptr, block_name, UI_EMBOSS_PULLDOWN);
   pup->block->flag |= UI_BLOCK_POPUP_MEMORY | UI_BLOCK_IS_FLIP;
   pup->block->puphash = ui_popup_menu_hash(title);
   pup->layout = UI_block_layout(
@@ -389,7 +392,7 @@ uiPopupMenu *UI_popup_menu_begin_ex(bContext *C,
   uiLayoutSetOperatorContext(pup->layout, WM_OP_EXEC_REGION_WIN);
 
   /* create in advance so we can let buttons point to retval already */
-  pup->block->handle = MEM_callocN(sizeof(uiPopupBlockHandle), "uiPopupBlockHandle");
+  pup->block->handle = MEM_cnew<uiPopupBlockHandle>(__func__);
 
   /* create title button */
   if (title[0]) {
@@ -406,7 +409,7 @@ uiPopupMenu *UI_popup_menu_begin_ex(bContext *C,
                        0,
                        200,
                        UI_UNIT_Y,
-                       NULL,
+                       nullptr,
                        0.0,
                        0.0,
                        0,
@@ -415,7 +418,7 @@ uiPopupMenu *UI_popup_menu_begin_ex(bContext *C,
     }
     else {
       but = uiDefBut(
-          pup->block, UI_BTYPE_LABEL, 0, title, 0, 0, 200, UI_UNIT_Y, NULL, 0.0, 0.0, 0, 0, "");
+          pup->block, UI_BTYPE_LABEL, 0, title, 0, 0, 200, UI_UNIT_Y, nullptr, 0.0, 0.0, 0, 0, "");
       but->drawflag = UI_BUT_TEXT_LEFT;
     }
 
@@ -440,8 +443,8 @@ void UI_popup_menu_end(bContext *C, uiPopupMenu *pup)
 {
   wmWindow *window = CTX_wm_window(C);
   uiPopupBlockHandle *menu;
-  uiBut *but = NULL;
-  ARegion *butregion = NULL;
+  uiBut *but = nullptr;
+  ARegion *butregion = nullptr;
 
   pup->popup = true;
   pup->mx = window->eventstate->xy[0];
@@ -452,7 +455,7 @@ void UI_popup_menu_end(bContext *C, uiPopupMenu *pup)
     butregion = pup->butregion;
   }
 
-  menu = ui_popup_block_create(C, butregion, but, NULL, ui_block_func_POPUP, pup, NULL);
+  menu = ui_popup_block_create(C, butregion, but, nullptr, ui_block_func_POPUP, pup, nullptr);
   menu->popup = true;
 
   UI_popup_handlers_add(C, &window->modalhandlers, menu, 0);
@@ -467,7 +470,7 @@ bool UI_popup_menu_end_or_cancel(bContext *C, uiPopupMenu *pup)
     UI_popup_menu_end(C, pup);
     return true;
   }
-  UI_block_layout_resolve(pup->block, NULL, NULL);
+  UI_block_layout_resolve(pup->block, nullptr, nullptr);
   MEM_freeN(pup->block->handle);
   UI_block_free(C, pup->block);
   MEM_freeN(pup);
@@ -487,7 +490,7 @@ uiLayout *UI_popup_menu_layout(uiPopupMenu *pup)
 
 void UI_popup_menu_reports(bContext *C, ReportList *reports)
 {
-  uiPopupMenu *pup = NULL;
+  uiPopupMenu *pup = nullptr;
   uiLayout *layout;
 
   if (!CTX_wm_window(C)) {
@@ -502,7 +505,7 @@ void UI_popup_menu_reports(bContext *C, ReportList *reports)
       continue;
     }
 
-    if (pup == NULL) {
+    if (pup == nullptr) {
       char title[UI_MAX_DRAW_STR];
       BLI_snprintf(title, sizeof(title), "%s: %s", IFACE_("Report"), report->typestr);
       /* popup_menu stuff does just what we need (but pass meaningful block name) */
@@ -540,7 +543,7 @@ int UI_popup_menu_invoke(bContext *C, const char *idname, ReportList *reports)
   uiLayout *layout;
   MenuType *mt = WM_menutype_find(idname, true);
 
-  if (mt == NULL) {
+  if (mt == nullptr) {
     BKE_reportf(reports, RPT_ERROR, "Menu \"%s\" not found", idname);
     return OPERATOR_CANCELLED;
   }
@@ -572,7 +575,7 @@ void UI_popup_block_invoke_ex(
   wmWindow *window = CTX_wm_window(C);
   uiPopupBlockHandle *handle;
 
-  handle = ui_popup_block_create(C, NULL, NULL, func, NULL, arg, arg_free);
+  handle = ui_popup_block_create(C, nullptr, nullptr, func, nullptr, arg, arg_free);
   handle->popup = true;
 
   /* It can be useful to disable refresh (even though it will work)
@@ -580,7 +583,8 @@ void UI_popup_block_invoke_ex(
   handle->can_refresh = can_refresh;
 
   UI_popup_handlers_add(C, &window->modalhandlers, handle, 0);
-  UI_block_active_only_flagged_buttons(C, handle->region, handle->region->uiblocks.first);
+  UI_block_active_only_flagged_buttons(
+      C, handle->region, static_cast<uiBlock *>(handle->region->uiblocks.first));
   WM_event_add_mousemove(window);
 }
 
@@ -599,7 +603,7 @@ void UI_popup_block_ex(bContext *C,
   wmWindow *window = CTX_wm_window(C);
   uiPopupBlockHandle *handle;
 
-  handle = ui_popup_block_create(C, NULL, NULL, func, NULL, arg, NULL);
+  handle = ui_popup_block_create(C, nullptr, nullptr, func, nullptr, arg, nullptr);
   handle->popup = true;
   handle->retvalue = 1;
   handle->can_refresh = true;
@@ -611,7 +615,8 @@ void UI_popup_block_ex(bContext *C,
   // handle->opcontext = opcontext;
 
   UI_popup_handlers_add(C, &window->modalhandlers, handle, 0);
-  UI_block_active_only_flagged_buttons(C, handle->region, handle->region->uiblocks.first);
+  UI_block_active_only_flagged_buttons(
+      C, handle->region, static_cast<uiBlock *>(handle->region->uiblocks.first));
   WM_event_add_mousemove(window);
 }
 
@@ -621,7 +626,7 @@ void uiPupBlockOperator(bContext *C, uiBlockCreateFunc func, wmOperator *op, wmO
   wmWindow *window = CTX_wm_window(C);
   uiPopupBlockHandle *handle;
 
-  handle = ui_popup_block_create(C, NULL, NULL, func, NULL, op, NULL);
+  handle = ui_popup_block_create(C, nullptr, nullptr, func, nullptr, op, nullptr);
   handle->popup = 1;
   handle->retvalue = 1;
   handle->can_refresh = true;
@@ -638,7 +643,7 @@ void uiPupBlockOperator(bContext *C, uiBlockCreateFunc func, wmOperator *op, wmO
 
 void UI_popup_block_close(bContext *C, wmWindow *win, uiBlock *block)
 {
-  /* if loading new .blend while popup is open, window will be NULL */
+  /* if loading new .blend while popup is open, window will be nullptr */
   if (block->handle) {
     if (win) {
       const bScreen *screen = WM_window_get_active_screen(win);
diff --git a/source/blender/editors/interface/interface_region_popover.c b/source/blender/editors/interface/interface_region_popover.cc
index 7c7c9e887dd..2e10261a4f7 100644
--- a/source/blender/editors/interface/interface_region_popover.c
+++ b/source/blender/editors/interface/interface_region_popover.cc
@@ -80,7 +80,7 @@ static void ui_popover_create_block(bContext *C, uiPopover *pup, wmOperatorCallC
 
   const uiStyle *style = UI_style_get_dpi();
 
-  pup->block = UI_block_begin(C, NULL, __func__, UI_EMBOSS);
+  pup->block = UI_block_begin(C, nullptr, __func__, UI_EMBOSS);
   UI_block_flag_enable(pup->block, UI_BLOCK_KEEP_OPEN | UI_BLOCK_POPOVER);
 #ifdef USE_UI_POPOVER_ONCE
   if (pup->is_once) {
@@ -104,7 +104,7 @@ static void ui_popover_create_block(bContext *C, uiPopover *pup, wmOperatorCallC
 
 static uiBlock *ui_block_func_POPOVER(bContext *C, uiPopupBlockHandle *handle, void *arg_pup)
 {
-  uiPopover *pup = arg_pup;
+  uiPopover *pup = static_cast<uiPopover *>(arg_pup);
 
   /* Create UI block and layout now if it wasn't done between begin/end. */
   if (!pup->layout) {
@@ -113,10 +113,10 @@ static uiBlock *ui_block_func_POPOVER(bContext *C, uiPopupBlockHandle *handle, v
     if (pup->menu_func) {
       pup->block->handle = handle;
       pup->menu_func(C, pup->layout, pup->menu_arg);
-      pup->block->handle = NULL;
+      pup->block->handle = nullptr;
     }
 
-    pup->layout = NULL;
+    pup->layout = nullptr;
   }
 
   /* Setup and resolve UI layout for block. */
@@ -185,10 +185,10 @@ static uiBlock *ui_block_func_POPOVER(bContext *C, uiPopupBlockHandle *handle, v
     block->minbounds = UI_MENU_WIDTH_MIN;
 
     if (!handle->refresh) {
-      uiBut *but = NULL;
-      uiBut *but_first = NULL;
+      uiBut *but = nullptr;
+      uiBut *but_first = nullptr;
       LISTBASE_FOREACH (uiBut *, but_iter, &block->buttons) {
-        if ((but_first == NULL) && ui_but_is_editable(but_iter)) {
+        if ((but_first == nullptr) && ui_but_is_editable(but_iter)) {
           but_first = but_iter;
         }
         if (but_iter->flag & (UI_SELECT | UI_SELECT_DRAW)) {
@@ -219,8 +219,8 @@ static uiBlock *ui_block_func_POPOVER(bContext *C, uiPopupBlockHandle *handle, v
 
 static void ui_block_free_func_POPOVER(void *arg_pup)
 {
-  uiPopover *pup = arg_pup;
-  if (pup->keymap != NULL) {
+  uiPopover *pup = static_cast<uiPopover *>(arg_pup);
+  if (pup->keymap != nullptr) {
     wmWindow *window = pup->window;
     WM_event_remove_keymap_handler(&window->modalhandlers, pup->keymap);
   }
@@ -235,7 +235,7 @@ uiPopupBlockHandle *ui_popover_panel_create(
   const PanelType *panel_type = (PanelType *)arg;
 
   /* Create popover, buttons are created from callback. */
-  uiPopover *pup = MEM_callocN(sizeof(uiPopover), __func__);
+  uiPopover *pup = MEM_cnew<uiPopover>(__func__);
   pup->but = but;
 
   /* FIXME: maybe one day we want non panel popovers? */
@@ -262,7 +262,7 @@ uiPopupBlockHandle *ui_popover_panel_create(
   /* Create popup block. */
   uiPopupBlockHandle *handle;
   handle = ui_popup_block_create(
-      C, butregion, but, NULL, ui_block_func_POPOVER, pup, ui_block_free_func_POPOVER);
+      C, butregion, but, nullptr, ui_block_func_POPOVER, pup, ui_block_free_func_POPOVER);
   handle->can_refresh = true;
 
   /* Add handlers. If attached to a button, the button will already
@@ -286,7 +286,7 @@ int UI_popover_panel_invoke(bContext *C, const char *idname, bool keep_open, Rep
 {
   uiLayout *layout;
   PanelType *pt = WM_paneltype_find(idname, true);
-  if (pt == NULL) {
+  if (pt == nullptr) {
     BKE_reportf(reports, RPT_ERROR, "Panel \"%s\" not found", idname);
     return OPERATOR_CANCELLED;
   }
@@ -296,23 +296,23 @@ int UI_popover_panel_invoke(bContext *C, const char *idname, bool keep_open, Rep
     return (OPERATOR_CANCELLED | OPERATOR_PASS_THROUGH);
   }
 
-  uiBlock *block = NULL;
+  uiBlock *block = nullptr;
   if (keep_open) {
     uiPopupBlockHandle *handle = ui_popover_panel_create(
-        C, NULL, NULL, ui_item_paneltype_func, pt);
-    uiPopover *pup = handle->popup_create_vars.arg;
+        C, nullptr, nullptr, ui_item_paneltype_func, pt);
+    uiPopover *pup = static_cast<uiPopover *>(handle->popup_create_vars.arg);
     block = pup->block;
   }
   else {
     uiPopover *pup = UI_popover_begin(C, U.widget_unit * pt->ui_units_x, false);
     layout = UI_popover_layout(pup);
     UI_paneltype_draw(C, pt, layout);
-    UI_popover_end(C, pup, NULL);
+    UI_popover_end(C, pup, nullptr);
     block = pup->block;
   }
 
   if (block) {
-    uiPopupBlockHandle *handle = block->handle;
+    uiPopupBlockHandle *handle = static_cast<uiPopupBlockHandle *>(block->handle);
     UI_block_active_only_flagged_buttons(C, handle->region, block);
   }
   return OPERATOR_INTERFACE;
@@ -326,20 +326,20 @@ int UI_popover_panel_invoke(bContext *C, const char *idname, bool keep_open, Rep
 
 uiPopover *UI_popover_begin(bContext *C, int ui_menu_width, bool from_active_button)
 {
-  uiPopover *pup = MEM_callocN(sizeof(uiPopover), "popover menu");
+  uiPopover *pup = MEM_cnew<uiPopover>(__func__);
   if (ui_menu_width == 0) {
     ui_menu_width = U.widget_unit * UI_POPOVER_WIDTH_UNITS;
   }
   pup->ui_size_x = ui_menu_width;
 
-  ARegion *butregion = NULL;
-  uiBut *but = NULL;
+  ARegion *butregion = nullptr;
+  uiBut *but = nullptr;
 
   if (from_active_button) {
     butregion = CTX_wm_region(C);
     but = UI_region_active_but_get(butregion);
-    if (but == NULL) {
-      butregion = NULL;
+    if (but == nullptr) {
+      butregion = nullptr;
     }
   }
 
@@ -350,14 +350,14 @@ uiPopover *UI_popover_begin(bContext *C, int ui_menu_width, bool from_active_but
   ui_popover_create_block(C, pup, WM_OP_EXEC_REGION_WIN);
 
   /* create in advance so we can let buttons point to retval already */
-  pup->block->handle = MEM_callocN(sizeof(uiPopupBlockHandle), "uiPopupBlockHandle");
+  pup->block->handle = MEM_cnew<uiPopupBlockHandle>(__func__);
 
   return pup;
 }
 
 static void popover_keymap_fn(wmKeyMap *UNUSED(keymap), wmKeyMapItem *UNUSED(kmi), void *user_data)
 {
-  uiPopover *pup = user_data;
+  uiPopover *pup = static_cast<uiPopover *>(user_data);
   pup->block->handle->menuretval = UI_RETURN_OK;
 }
 
@@ -376,8 +376,13 @@ void UI_popover_end(bContext *C, uiPopover *pup, wmKeyMap *keymap)
     WM_event_set_keymap_handler_post_callback(pup->keymap_handler, popover_keymap_fn, pup);
   }
 
-  handle = ui_popup_block_create(
-      C, pup->butregion, pup->but, NULL, ui_block_func_POPOVER, pup, ui_block_free_func_POPOVER);
+  handle = ui_popup_block_create(C,
+                                 pup->butregion,
+                                 pup->but,
+                                 nullptr,
+                                 ui_block_func_POPOVER,
+                                 pup,
+                                 ui_block_free_func_POPOVER);
 
   /* Add handlers. */
   UI_popup_handlers_add(C, &window->modalhandlers, handle, 0);
diff --git a/source/blender/editors/interface/interface_region_popup.c b/source/blender/editors/interface/interface_region_popup.cc
index 2f2556225b5..74c228e3338 100644
--- a/source/blender/editors/interface/interface_region_popup.c
+++ b/source/blender/editors/interface/interface_region_popup.cc
@@ -7,9 +7,9 @@
  * PopUp Region (Generic)
  */
 
-#include <stdarg.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cstdarg>
+#include <cstdlib>
+#include <cstring>
 
 #include "MEM_guardedalloc.h"
 
@@ -120,7 +120,7 @@ static void ui_popup_block_position(wmWindow *window,
   short dir1 = 0, dir2 = 0;
 
   if (!handle->refresh) {
-    bool left = 0, right = 0, top = 0, down = 0;
+    bool left = false, right = false, top = false, down = false;
 
     const int win_x = WM_window_pixels_x(window);
     const int win_y = WM_window_pixels_y(window);
@@ -131,24 +131,24 @@ static void ui_popup_block_position(wmWindow *window,
 
     /* check if there's space at all */
     if (butrct.xmin - max_size_x + center_x > 0.0f) {
-      left = 1;
+      left = true;
     }
     if (butrct.xmax + max_size_x - center_x < win_x) {
-      right = 1;
+      right = true;
     }
     if (butrct.ymin - max_size_y + center_y > 0.0f) {
-      down = 1;
+      down = true;
     }
     if (butrct.ymax + max_size_y - center_y < win_y) {
-      top = 1;
+      top = true;
     }
 
     if (top == 0 && down == 0) {
       if (butrct.ymin - max_size_y < win_y - butrct.ymax - max_size_y) {
-        top = 1;
+        top = true;
       }
       else {
-        down = 1;
+        down = true;
       }
     }
 
@@ -335,7 +335,7 @@ static void ui_popup_block_position(wmWindow *window,
   }
 
   /* Keep a list of these, needed for pull-down menus. */
-  uiSafetyRct *saferct = MEM_callocN(sizeof(uiSafetyRct), "uiSafetyRct");
+  uiSafetyRct *saferct = MEM_cnew<uiSafetyRct>(__func__);
   saferct->parent = butrct;
   saferct->safety = block->safety;
   BLI_freelistN(&block->saferct);
@@ -520,7 +520,7 @@ static void ui_popup_block_remove(bContext *C, uiPopupBlockHandle *handle)
   CTX_wm_window_set(C, win);
   ui_region_temp_remove(C, screen, handle->region);
 
-  /* Reset context (area and region were NULL'ed when changing context window). */
+  /* Reset context (area and region were nullptr'ed when changing context window). */
   CTX_wm_window_set(C, ctx_win);
   CTX_wm_area_set(C, ctx_area);
   CTX_wm_region_set(C, ctx_region);
@@ -548,10 +548,10 @@ uiBlock *ui_popup_block_refresh(bContext *C,
   const uiBlockHandleCreateFunc handle_create_func = handle->popup_create_vars.handle_create_func;
   void *arg = handle->popup_create_vars.arg;
 
-  uiBlock *block_old = region->uiblocks.first;
+  uiBlock *block_old = static_cast<uiBlock *>(region->uiblocks.first);
   uiBlock *block;
 
-  handle->refresh = (block_old != NULL);
+  handle->refresh = (block_old != nullptr);
 
   BLI_assert(!handle->refresh || handle->can_refresh);
 
@@ -573,7 +573,7 @@ uiBlock *ui_popup_block_refresh(bContext *C,
 
   /* ensure we don't use mouse coords here! */
 #ifdef DEBUG
-  window->eventstate = NULL;
+  window->eventstate = nullptr;
 #endif
 
   if (block->handle) {
@@ -588,7 +588,7 @@ uiBlock *ui_popup_block_refresh(bContext *C,
   region->regiondata = handle;
 
   /* set UI_BLOCK_NUMSELECT before UI_block_end() so we get alphanumeric keys assigned */
-  if (but == NULL) {
+  if (but == nullptr) {
     block->flag |= UI_BLOCK_POPUP;
   }
 
@@ -596,7 +596,7 @@ uiBlock *ui_popup_block_refresh(bContext *C,
   UI_block_theme_style_set(block, UI_BLOCK_THEME_STYLE_POPUP);
 
   /* defer this until blocks are translated (below) */
-  block->oldblock = NULL;
+  block->oldblock = nullptr;
 
   if (!block->endblock) {
     UI_block_end_ex(
@@ -610,9 +610,8 @@ uiBlock *ui_popup_block_refresh(bContext *C,
     handle->direction = block->direction;
   }
   else {
-    uiSafetyRct *saferct;
     /* Keep a list of these, needed for pull-down menus. */
-    saferct = MEM_callocN(sizeof(uiSafetyRct), "uiSafetyRct");
+    uiSafetyRct *saferct = MEM_cnew<uiSafetyRct>(__func__);
     saferct->safety = block->safety;
     BLI_addhead(&block->saferct, saferct);
   }
@@ -760,7 +759,6 @@ uiPopupBlockHandle *ui_popup_block_create(bContext *C,
   static ARegionType type;
   ARegion *region;
   uiBlock *block;
-  uiPopupBlockHandle *handle;
 
   /* disable tooltips from buttons below */
   if (activebut) {
@@ -770,7 +768,7 @@ uiPopupBlockHandle *ui_popup_block_create(bContext *C,
   WM_cursor_set(window, WM_CURSOR_DEFAULT);
 
   /* create handle */
-  handle = MEM_callocN(sizeof(uiPopupBlockHandle), "uiPopupBlockHandle");
+  uiPopupBlockHandle *handle = MEM_cnew<uiPopupBlockHandle>(__func__);
 
   /* store context for operator */
   handle->ctx_area = CTX_wm_area(C);
@@ -782,7 +780,7 @@ uiPopupBlockHandle *ui_popup_block_create(bContext *C,
   handle->popup_create_vars.arg = arg;
   handle->popup_create_vars.arg_free = arg_free;
   handle->popup_create_vars.but = but;
-  handle->popup_create_vars.butregion = but ? butregion : NULL;
+  handle->popup_create_vars.butregion = but ? butregion : nullptr;
   copy_v2_v2_int(handle->popup_create_vars.event_xy, window->eventstate->xy);
 
   /* don't allow by default, only if popup type explicitly supports it */
@@ -816,7 +814,7 @@ void ui_popup_block_free(bContext *C, uiPopupBlockHandle *handle)
   /* If this popup is created from a popover which does NOT have keep-open flag set,
    * then close the popover too. We could extend this to other popup types too. */
   ARegion *region = handle->popup_create_vars.butregion;
-  if (region != NULL) {
+  if (region != nullptr) {
     LISTBASE_FOREACH (uiBlock *, block, &region->uiblocks) {
       if (block->handle && (block->flag & UI_BLOCK_POPOVER) &&
           (block->flag & UI_BLOCK_KEEP_OPEN) == 0) {
diff --git a/source/blender/editors/interface/interface_regions.c b/source/blender/editors/interface/interface_regions.cc
index ea6d293e52f..1a2c1f7919c 100644
--- a/source/blender/editors/interface/interface_regions.c
+++ b/source/blender/editors/interface/interface_regions.cc
@@ -25,7 +25,7 @@
 
 ARegion *ui_region_temp_add(bScreen *screen)
 {
-  ARegion *region = MEM_callocN(sizeof(ARegion), __func__);
+  ARegion *region = MEM_cnew<ARegion>(__func__);
   BLI_addtail(&screen->regionbase, region);
 
   region->regiontype = RGN_TYPE_TEMPORARY;
@@ -45,6 +45,6 @@ void ui_region_temp_remove(bContext *C, bScreen *screen, ARegion *region)
   }
 
   ED_region_exit(C, region);
-  BKE_area_region_free(NULL, region); /* NULL: no spacetype */
+  BKE_area_region_free(nullptr, region); /* nullptr: no spacetype */
   BLI_freelinkN(&screen->regionbase, region);
 }
diff --git a/source/blender/editors/interface/interface_style.c b/source/blender/editors/interface/interface_style.cc
index 76023f3033f..b4e97f8a396 100644
--- a/source/blender/editors/interface/interface_style.c
+++ b/source/blender/editors/interface/interface_style.cc
@@ -5,11 +5,11 @@
  * \ingroup edinterface
  */
 
-#include <limits.h>
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+#include <climits>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
 
 #include "MEM_guardedalloc.h"
 
@@ -57,7 +57,7 @@
 
 static uiStyle *ui_style_new(ListBase *styles, const char *name, short uifont_id)
 {
-  uiStyle *style = MEM_callocN(sizeof(uiStyle), "new style");
+  uiStyle *style = MEM_cnew<uiStyle>(__func__);
 
   BLI_addtail(styles, style);
   BLI_strncpy(style->name, name, MAX_STYLE_NAME);
@@ -108,14 +108,14 @@ static uiStyle *ui_style_new(ListBase *styles, const char *name, short uifont_id
 
 static uiFont *uifont_to_blfont(int id)
 {
-  uiFont *font = U.uifonts.first;
+  uiFont *font = static_cast<uiFont *>(U.uifonts.first);
 
   for (; font; font = font->next) {
     if (font->uifont_id == id) {
       return font;
     }
   }
-  return U.uifonts.first;
+  return static_cast<uiFont *>(U.uifonts.first);
 }
 
 /* *************** draw ************************ */
@@ -198,7 +198,7 @@ void UI_fontstyle_draw(const uiFontStyle *fs,
                        const uchar col[4],
                        const struct uiFontStyleDraw_Params *fs_params)
 {
-  UI_fontstyle_draw_ex(fs, rect, str, str_len, col, fs_params, NULL, NULL, NULL);
+  UI_fontstyle_draw_ex(fs, rect, str, str_len, col, fs_params, nullptr, nullptr, nullptr);
 }
 
 void UI_fontstyle_draw_rotated(const uiFontStyle *fs,
@@ -284,17 +284,13 @@ void UI_fontstyle_draw_simple_backdrop(const uiFontStyle *fs,
     const float decent = BLF_descender(fs->uifont_id);
     const float margin = height / 4.0f;
 
+    rctf rect;
+    rect.xmin = x - margin;
+    rect.xmax = x + width + margin;
+    rect.ymin = (y + decent) - margin;
+    rect.ymax = (y + decent) + height + margin;
     UI_draw_roundbox_corner_set(UI_CNR_ALL);
-    UI_draw_roundbox_4fv(
-        &(const rctf){
-            .xmin = x - margin,
-            .xmax = x + width + margin,
-            .ymin = (y + decent) - margin,
-            .ymax = (y + decent) + height + margin,
-        },
-        true,
-        margin,
-        col_bg);
+    UI_draw_roundbox_4fv(&rect, true, margin, col_bg);
   }
 
   BLF_position(fs->uifont_id, x, y, 0.0f);
@@ -307,12 +303,12 @@ void UI_fontstyle_draw_simple_backdrop(const uiFontStyle *fs,
 const uiStyle *UI_style_get(void)
 {
 #if 0
-  uiStyle *style = NULL;
+  uiStyle *style = nullptr;
   /* offset is two struct uiStyle pointers */
   style = BLI_findstring(&U.uistyles, "Unifont Style", sizeof(style) * 2);
-  return (style != NULL) ? style : U.uistyles.first;
+  return (style != nullptr) ? style : U.uistyles.first;
 #else
-  return U.uistyles.first;
+  return static_cast<const uiStyle *>(U.uistyles.first);
 #endif
 }
 
@@ -378,7 +374,7 @@ int UI_fontstyle_height_max(const uiFontStyle *fs)
 
 void uiStyleInit(void)
 {
-  const uiStyle *style = U.uistyles.first;
+  const uiStyle *style = static_cast<uiStyle *>(U.uistyles.first);
 
   /* recover from uninitialized dpi */
   if (U.dpi == 0) {
@@ -400,11 +396,11 @@ void uiStyleInit(void)
     blf_mono_font_render = -1;
   }
 
-  uiFont *font_first = U.uifonts.first;
+  uiFont *font_first = static_cast<uiFont *>(U.uifonts.first);
 
   /* default builtin */
-  if (font_first == NULL) {
-    font_first = MEM_callocN(sizeof(uiFont), "ui font");
+  if (font_first == nullptr) {
+    font_first = MEM_cnew<uiFont>(__func__);
     BLI_addtail(&U.uifonts, font_first);
   }
 
@@ -439,7 +435,7 @@ void uiStyleInit(void)
     }
   }
 
-  if (style == NULL) {
+  if (style == nullptr) {
     style = ui_style_new(&U.uistyles, "Default Style", UIFONT_DEFAULT);
   }
 
diff --git a/source/blender/editors/interface/interface_utils.c b/source/blender/editors/interface/interface_utils.cc
index 728d42a9353..b796f07c24b 100644
--- a/source/blender/editors/interface/interface_utils.c
+++ b/source/blender/editors/interface/interface_utils.cc
@@ -5,17 +5,16 @@
  * \ingroup edinterface
  */
 
-#include <ctype.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
 
 #include "DNA_object_types.h"
 #include "DNA_screen_types.h"
 
 #include "ED_screen.h"
 
-#include "BLI_alloca.h"
 #include "BLI_listbase.h"
 #include "BLI_math.h"
 #include "BLI_string.h"
@@ -55,12 +54,12 @@ uiBut *uiDefAutoButR(uiBlock *block,
                      int width,
                      int height)
 {
-  uiBut *but = NULL;
+  uiBut *but = nullptr;
 
   switch (RNA_property_type(prop)) {
     case PROP_BOOLEAN: {
       if (RNA_property_array_check(prop) && index == -1) {
-        return NULL;
+        return nullptr;
       }
 
       if (icon && name && name[0] == '\0') {
@@ -79,7 +78,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                  0,
                                  -1,
                                  -1,
-                                 NULL);
+                                 nullptr);
       }
       else if (icon) {
         but = uiDefIconTextButR_prop(block,
@@ -98,7 +97,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                      0,
                                      -1,
                                      -1,
-                                     NULL);
+                                     nullptr);
       }
       else {
         but = uiDefButR_prop(block,
@@ -116,7 +115,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                              0,
                              -1,
                              -1,
-                             NULL);
+                             nullptr);
       }
       break;
     }
@@ -139,10 +138,10 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                0,
                                0,
                                0,
-                               NULL);
+                               nullptr);
         }
         else {
-          return NULL;
+          return nullptr;
         }
       }
       else if (RNA_property_subtype(prop) == PROP_PERCENTAGE ||
@@ -162,11 +161,25 @@ uiBut *uiDefAutoButR(uiBlock *block,
                              0,
                              -1,
                              -1,
-                             NULL);
+                             nullptr);
       }
       else {
-        but = uiDefButR_prop(
-            block, UI_BTYPE_NUM, 0, name, x, y, width, height, ptr, prop, index, 0, 0, 0, 0, NULL);
+        but = uiDefButR_prop(block,
+                             UI_BTYPE_NUM,
+                             0,
+                             name,
+                             x,
+                             y,
+                             width,
+                             height,
+                             ptr,
+                             prop,
+                             index,
+                             0,
+                             0,
+                             0,
+                             0,
+                             nullptr);
       }
 
       if (RNA_property_flag(prop) & PROP_TEXTEDIT_UPDATE) {
@@ -191,14 +204,14 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                  0,
                                  -1,
                                  -1,
-                                 NULL);
+                                 nullptr);
       }
       else if (icon) {
         but = uiDefIconTextButR_prop(block,
                                      UI_BTYPE_MENU,
                                      0,
                                      icon,
-                                     NULL,
+                                     nullptr,
                                      x,
                                      y,
                                      width,
@@ -210,7 +223,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                      0,
                                      -1,
                                      -1,
-                                     NULL);
+                                     nullptr);
       }
       else {
         but = uiDefButR_prop(block,
@@ -228,7 +241,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                              0,
                              -1,
                              -1,
-                             NULL);
+                             nullptr);
       }
       break;
     case PROP_STRING:
@@ -248,7 +261,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                  0,
                                  -1,
                                  -1,
-                                 NULL);
+                                 nullptr);
       }
       else if (icon) {
         but = uiDefIconTextButR_prop(block,
@@ -267,7 +280,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                      0,
                                      -1,
                                      -1,
-                                     NULL);
+                                     nullptr);
       }
       else {
         but = uiDefButR_prop(block,
@@ -285,7 +298,7 @@ uiBut *uiDefAutoButR(uiBlock *block,
                              0,
                              -1,
                              -1,
-                             NULL);
+                             nullptr);
       }
 
       if (RNA_property_flag(prop) & PROP_TEXTEDIT_UPDATE) {
@@ -319,20 +332,21 @@ uiBut *uiDefAutoButR(uiBlock *block,
                                    0,
                                    -1,
                                    -1,
-                                   NULL);
-      ui_but_add_search(but, ptr, prop, NULL, NULL);
+                                   nullptr);
+      ui_but_add_search(but, ptr, prop, nullptr, nullptr);
       break;
     }
     case PROP_COLLECTION: {
       char text[256];
       BLI_snprintf(
           text, sizeof(text), IFACE_("%d items"), RNA_property_collection_length(ptr, prop));
-      but = uiDefBut(block, UI_BTYPE_LABEL, 0, text, x, y, width, height, NULL, 0, 0, 0, 0, NULL);
+      but = uiDefBut(
+          block, UI_BTYPE_LABEL, 0, text, x, y, width, height, nullptr, 0, 0, 0, 0, nullptr);
       UI_but_flag_enable(but, UI_BUT_DISABLED);
       break;
     }
     default:
-      but = NULL;
+      but = nullptr;
       break;
   }
 
@@ -414,7 +428,7 @@ eAutoPropButsReturn uiDefAutoButsRNA(uiLayout *layout,
       case UI_BUT_LABEL_ALIGN_NONE:
       default:
         col = layout;
-        name = NULL; /* no smart label alignment, show default name with button */
+        name = nullptr; /* no smart label alignment, show default name with button */
         break;
     }
 
@@ -440,7 +454,7 @@ eAutoPropButsReturn uiDefAutoButsRNA(uiLayout *layout,
 
 /* *** RNA collection search menu *** */
 
-typedef struct CollItemSearch {
+struct CollItemSearch {
   struct CollItemSearch *next, *prev;
   void *data;
   char *name;
@@ -449,7 +463,7 @@ typedef struct CollItemSearch {
   bool is_id;
   int name_prefix_offset;
   uint has_sep_char : 1;
-} CollItemSearch;
+};
 
 static bool add_collection_search_item(CollItemSearch *cis,
                                        const bool requires_exact_data_name,
@@ -462,10 +476,11 @@ static bool add_collection_search_item(CollItemSearch *cis,
    * name prefix for showing the library status. */
   int name_prefix_offset = cis->name_prefix_offset;
   if (!has_id_icon && cis->is_id && !requires_exact_data_name) {
-    cis->iconid = UI_icon_from_library(cis->data);
+    cis->iconid = UI_icon_from_library(static_cast<const ID *>(cis->data));
     /* No need to re-allocate, string should be shorter than before (lib status prefix is
      * removed). */
-    BKE_id_full_name_ui_prefix_get(name_buf, cis->data, false, UI_SEP_CHAR, &name_prefix_offset);
+    BKE_id_full_name_ui_prefix_get(
+        name_buf, static_cast<const ID *>(cis->data), false, UI_SEP_CHAR, &name_prefix_offset);
     BLI_assert(strlen(name_buf) <= MEM_allocN_len(cis->name));
     strcpy(cis->name, name_buf);
   }
@@ -478,15 +493,12 @@ static bool add_collection_search_item(CollItemSearch *cis,
                             name_prefix_offset);
 }
 
-void ui_rna_collection_search_update_fn(const struct bContext *C,
-                                        void *arg,
-                                        const char *str,
-                                        uiSearchItems *items,
-                                        const bool is_first)
+void ui_rna_collection_search_update_fn(
+    const bContext *C, void *arg, const char *str, uiSearchItems *items, const bool is_first)
 {
-  uiRNACollectionSearch *data = arg;
+  uiRNACollectionSearch *data = static_cast<uiRNACollectionSearch *>(arg);
   const int flag = RNA_property_flag(data->target_prop);
-  ListBase *items_list = MEM_callocN(sizeof(ListBase), "items_list");
+  ListBase *items_list = MEM_cnew<ListBase>("items_list");
   const bool is_ptr_target = (RNA_property_type(data->target_prop) == PROP_POINTER);
   /* For non-pointer properties, UI code acts entirely based on the item's name. So the name has to
    * match the RNA name exactly. So only for pointer properties, the name can be modified to add
@@ -497,7 +509,7 @@ void ui_rna_collection_search_update_fn(const struct bContext *C,
   char *name;
   bool has_id_icon = false;
 
-  StringSearch *search = skip_filter ? NULL : BLI_string_search_new();
+  StringSearch *search = skip_filter ? nullptr : BLI_string_search_new();
 
   /* build a temporary list of relevant items first */
   int item_index = 0;
@@ -522,18 +534,17 @@ void ui_rna_collection_search_update_fn(const struct bContext *C,
     const bool is_id = itemptr.type && RNA_struct_is_ID(itemptr.type);
 
     if (is_id) {
-      iconid = ui_id_icon_get(C, itemptr.data, false);
+      iconid = ui_id_icon_get(C, static_cast<ID *>(itemptr.data), false);
       if (!ELEM(iconid, 0, ICON_BLANK1)) {
         has_id_icon = true;
       }
 
       if (requires_exact_data_name) {
-        name = RNA_struct_name_get_alloc(&itemptr, name_buf, sizeof(name_buf), NULL);
+        name = RNA_struct_name_get_alloc(&itemptr, name_buf, sizeof(name_buf), nullptr);
       }
       else {
-        const ID *id = itemptr.data;
-        BKE_id_full_name_ui_prefix_get(
-            name_buf, itemptr.data, true, UI_SEP_CHAR, &name_prefix_offset);
+        const ID *id = static_cast<ID *>(itemptr.data);
+        BKE_id_full_name_ui_prefix_get(name_buf, id, true, UI_SEP_CHAR, &name_prefix_offset);
         BLI_STATIC_ASSERT(sizeof(name_buf) >= MAX_ID_FULL_NAME_UI,
                           "Name string buffer should be big enough to hold full UI ID name");
         name = name_buf;
@@ -541,11 +552,11 @@ void ui_rna_collection_search_update_fn(const struct bContext *C,
       }
     }
     else {
-      name = RNA_struct_name_get_alloc(&itemptr, name_buf, sizeof(name_buf), NULL);
+      name = RNA_struct_name_get_alloc(&itemptr, name_buf, sizeof(name_buf), nullptr);
     }
 
     if (name) {
-      CollItemSearch *cis = MEM_callocN(sizeof(CollItemSearch), "CollectionItemSearch");
+      CollItemSearch *cis = MEM_cnew<CollItemSearch>(__func__);
       cis->data = itemptr.data;
       cis->name = BLI_strdup(name);
       cis->index = item_index;
@@ -597,7 +608,7 @@ void ui_rna_collection_search_update_fn(const struct bContext *C,
 
 int UI_icon_from_id(const ID *id)
 {
-  if (id == NULL) {
+  if (id == nullptr) {
     return ICON_NONE;
   }
 
@@ -608,7 +619,7 @@ int UI_icon_from_id(const ID *id)
     if (ob->type == OB_EMPTY) {
       return ICON_EMPTY_DATA;
     }
-    return UI_icon_from_id(ob->data);
+    return UI_icon_from_id(static_cast<const ID *>(ob->data));
   }
 
   /* otherwise get it through RNA, creating the pointer
@@ -761,7 +772,7 @@ bool UI_but_online_manual_id(const uiBut *but, char *r_str, size_t maxlength)
   return false;
 }
 
-bool UI_but_online_manual_id_from_active(const struct bContext *C, char *r_str, size_t maxlength)
+bool UI_but_online_manual_id_from_active(const bContext *C, char *r_str, size_t maxlength)
 {
   uiBut *but = UI_context_active_but_get(C);
 
@@ -861,7 +872,7 @@ void UI_but_ensure_in_view(const bContext *C, ARegion *region, const uiBut *but)
  * Modal Button Store API.
  *
  * Store for modal operators & handlers to register button pointers
- * which are maintained while drawing or NULL when removed.
+ * which are maintained while drawing or nullptr when removed.
  *
  * This is needed since button pointers are continuously freed and re-allocated.
  *
@@ -880,7 +891,7 @@ struct uiButStoreElem {
 
 uiButStore *UI_butstore_create(uiBlock *block)
 {
-  uiButStore *bs_handle = MEM_callocN(sizeof(uiButStore), __func__);
+  uiButStore *bs_handle = MEM_cnew<uiButStore>(__func__);
 
   bs_handle->block = block;
   BLI_addtail(&block->butstore, bs_handle);
@@ -899,7 +910,7 @@ void UI_butstore_free(uiBlock *block, uiButStore *bs_handle)
    * Ideally we would manage moving the 'uiButStore', keeping a correct state.
    * All things considered this is the most straightforward fix - Campbell.
    */
-  if (block != bs_handle->block && bs_handle->block != NULL) {
+  if (block != bs_handle->block && bs_handle->block != nullptr) {
     block = bs_handle->block;
   }
 
@@ -912,7 +923,7 @@ void UI_butstore_free(uiBlock *block, uiButStore *bs_handle)
 
 bool UI_butstore_is_valid(uiButStore *bs)
 {
-  return (bs->block != NULL);
+  return (bs->block != nullptr);
 }
 
 bool UI_butstore_is_registered(uiBlock *block, uiBut *but)
@@ -930,7 +941,7 @@ bool UI_butstore_is_registered(uiBlock *block, uiBut *but)
 
 void UI_butstore_register(uiButStore *bs_handle, uiBut **but_p)
 {
-  uiButStoreElem *bs_elem = MEM_callocN(sizeof(uiButStoreElem), __func__);
+  uiButStoreElem *bs_elem = MEM_cnew<uiButStoreElem>(__func__);
   BLI_assert(*but_p);
   bs_elem->but_p = but_p;
 
@@ -968,9 +979,9 @@ bool UI_butstore_register_update(uiBlock *block, uiBut *but_dst, const uiBut *bu
 void UI_butstore_clear(uiBlock *block)
 {
   LISTBASE_FOREACH (uiButStore *, bs_handle, &block->butstore) {
-    bs_handle->block = NULL;
+    bs_handle->block = nullptr;
     LISTBASE_FOREACH (uiButStoreElem *, bs_elem, &bs_handle->items) {
-      *bs_elem->but_p = NULL;
+      *bs_elem->but_p = nullptr;
     }
   }
 }
@@ -984,14 +995,14 @@ void UI_butstore_update(uiBlock *block)
     }
   }
 
-  if (LIKELY(block->butstore.first == NULL)) {
+  if (LIKELY(block->butstore.first == nullptr)) {
     return;
   }
 
   /* warning, loop-in-loop, in practice we only store <10 buttons at a time,
    * so this isn't going to be a problem, if that changes old-new mapping can be cached first */
   LISTBASE_FOREACH (uiButStore *, bs_handle, &block->butstore) {
-    BLI_assert(ELEM(bs_handle->block, NULL, block) ||
+    BLI_assert(ELEM(bs_handle->block, nullptr, block) ||
                (block->oldblock && block->oldblock == bs_handle->block));
 
     if (bs_handle->block == block->oldblock) {
@@ -1001,7 +1012,7 @@ void UI_butstore_update(uiBlock *block)
         if (*bs_elem->but_p) {
           uiBut *but_new = ui_but_find_new(block, *bs_elem->but_p);
 
-          /* can be NULL if the buttons removed,
+          /* can be nullptr if the buttons removed,
            * NOTE: we could allow passing in a callback when buttons are removed
            * so the caller can cleanup */
           *bs_elem->but_p = but_new;
diff --git a/source/blender/editors/object/object_transform.cc b/source/blender/editors/object/object_transform.cc
index 36d70eeef64..235ffb61738 100644
--- a/source/blender/editors/object/object_transform.cc
+++ b/source/blender/editors/object/object_transform.cc
@@ -1263,12 +1263,12 @@ static int object_origin_set_exec(bContext *C, wmOperator *op)
   }
 
   /* reset flags */
-  for (int object_index = 0; object_index < objects.size(); object_index++) {
+  for (const int object_index : objects.index_range()) {
     Object *ob = objects[object_index];
     ob->flag &= ~OB_DONE;
 
     /* move active first */
-    if (ob == obact) {
+    if (ob == obact && objects.size() > 1) {
       memmove(&objects[1], objects.data(), object_index * sizeof(Object *));
       objects[0] = ob;
     }
diff --git a/source/blender/editors/render/render_intern.hh b/source/blender/editors/render/render_intern.hh
index fc40fb06851..4135a0d97a9 100644
--- a/source/blender/editors/render/render_intern.hh
+++ b/source/blender/editors/render/render_intern.hh
@@ -33,6 +33,8 @@ void SCENE_OT_view_layer_add(struct wmOperatorType *ot);
 void SCENE_OT_view_layer_remove(struct wmOperatorType *ot);
 void SCENE_OT_view_layer_add_aov(struct wmOperatorType *ot);
 void SCENE_OT_view_layer_remove_aov(struct wmOperatorType *ot);
+void SCENE_OT_view_layer_add_lightgroup(struct wmOperatorType *ot);
+void SCENE_OT_view_layer_remove_lightgroup(struct wmOperatorType *ot);
 
 void SCENE_OT_light_cache_bake(struct wmOperatorType *ot);
 void SCENE_OT_light_cache_free(struct wmOperatorType *ot);
diff --git a/source/blender/editors/render/render_ops.cc b/source/blender/editors/render/render_ops.cc
index 1583ce44ee5..f671b2f950d 100644
--- a/source/blender/editors/render/render_ops.cc
+++ b/source/blender/editors/render/render_ops.cc
@@ -39,6 +39,8 @@ void ED_operatortypes_render()
   WM_operatortype_append(SCENE_OT_view_layer_remove);
   WM_operatortype_append(SCENE_OT_view_layer_add_aov);
   WM_operatortype_append(SCENE_OT_view_layer_remove_aov);
+  WM_operatortype_append(SCENE_OT_view_layer_add_lightgroup);
+  WM_operatortype_append(SCENE_OT_view_layer_remove_lightgroup);
 
   WM_operatortype_append(SCENE_OT_render_view_add);
   WM_operatortype_append(SCENE_OT_render_view_remove);
diff --git a/source/blender/editors/render/render_shading.cc b/source/blender/editors/render/render_shading.cc
index f48ac99fe75..07a07b462ef 100644
--- a/source/blender/editors/render/render_shading.cc
+++ b/source/blender/editors/render/render_shading.cc
@@ -1115,6 +1115,86 @@ void SCENE_OT_view_layer_remove_aov(wmOperatorType *ot)
 /** \} */
 
 /* -------------------------------------------------------------------- */
+/** \name View Layer Add Lightgroup Operator
+ * \{ */
+
+static int view_layer_add_lightgroup_exec(bContext *C, wmOperator *UNUSED(op))
+{
+  Scene *scene = CTX_data_scene(C);
+  ViewLayer *view_layer = CTX_data_view_layer(C);
+
+  BKE_view_layer_add_lightgroup(view_layer);
+
+  if (scene->nodetree) {
+    ntreeCompositUpdateRLayers(scene->nodetree);
+  }
+
+  DEG_id_tag_update(&scene->id, 0);
+  DEG_relations_tag_update(CTX_data_main(C));
+  WM_event_add_notifier(C, NC_SCENE | ND_LAYER, scene);
+
+  return OPERATOR_FINISHED;
+}
+
+void SCENE_OT_view_layer_add_lightgroup(wmOperatorType *ot)
+{
+  /* identifiers */
+  ot->name = "Add Lightgroup";
+  ot->idname = "SCENE_OT_view_layer_add_lightgroup";
+  ot->description = "Add a Light Group";
+
+  /* api callbacks */
+  ot->exec = view_layer_add_lightgroup_exec;
+
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO | OPTYPE_INTERNAL;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name View Layer Remove Lightgroup Operator
+ * \{ */
+
+static int view_layer_remove_lightgroup_exec(bContext *C, wmOperator *UNUSED(op))
+{
+  Scene *scene = CTX_data_scene(C);
+  ViewLayer *view_layer = CTX_data_view_layer(C);
+
+  if (view_layer->active_lightgroup == nullptr) {
+    return OPERATOR_FINISHED;
+  }
+
+  BKE_view_layer_remove_lightgroup(view_layer, view_layer->active_lightgroup);
+
+  if (scene->nodetree) {
+    ntreeCompositUpdateRLayers(scene->nodetree);
+  }
+
+  DEG_id_tag_update(&scene->id, 0);
+  DEG_relations_tag_update(CTX_data_main(C));
+  WM_event_add_notifier(C, NC_SCENE | ND_LAYER, scene);
+
+  return OPERATOR_FINISHED;
+}
+
+void SCENE_OT_view_layer_remove_lightgroup(wmOperatorType *ot)
+{
+  /* identifiers */
+  ot->name = "Remove Lightgroup";
+  ot->idname = "SCENE_OT_view_layer_remove_lightgroup";
+  ot->description = "Remove Active Lightgroup";
+
+  /* api callbacks */
+  ot->exec = view_layer_remove_lightgroup_exec;
+
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO | OPTYPE_INTERNAL;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Light Cache Bake Operator
  * \{ */
 
diff --git a/source/blender/makesdna/DNA_layer_types.h b/source/blender/makesdna/DNA_layer_types.h
index 7b6fe3773f8..d5f7e25bb80 100644
--- a/source/blender/makesdna/DNA_layer_types.h
+++ b/source/blender/makesdna/DNA_layer_types.h
@@ -124,6 +124,21 @@ typedef struct ViewLayerAOV {
    * matches `eViewLayerAOVType` */
   int type;
 } ViewLayerAOV;
+
+/* Lightgroup Renderpass definition. */
+typedef struct ViewLayerLightgroup {
+  struct ViewLayerLightgroup *next, *prev;
+
+  /* Name of the Lightgroup */
+  char name[64];
+} ViewLayerLightgroup;
+
+/* Lightgroup membership information. */
+typedef struct LightgroupMembership {
+  /* Name of the Lightgroup */
+  char name[64];
+} LightgroupMembership;
+
 typedef struct ViewLayer {
   struct ViewLayer *next, *prev;
   /** MAX_NAME. */
@@ -164,6 +179,10 @@ typedef struct ViewLayer {
   ListBase aovs;
   ViewLayerAOV *active_aov;
 
+  /* List containing the 'ViewLayerLightgroup`s */
+  ListBase lightgroups;
+  ViewLayerLightgroup *active_lightgroup;
+
   /* Runtime data */
   /** ViewLayerEngineData. */
   ListBase drawdata;
diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index 30f80110f6e..54627e711ff 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -31,6 +31,7 @@ struct Curve;
 struct FluidsimSettings;
 struct GeometrySet;
 struct Ipo;
+struct LightgroupMembership;
 struct Material;
 struct Mesh;
 struct Object;
@@ -434,8 +435,10 @@ typedef struct Object {
 
   ObjectLineArt lineart;
 
+  /** Lightgroup membership information. */
+  struct LightgroupMembership *lightgroup;
+
   /** Runtime evaluation data (keep last). */
-  void *_pad9;
   Object_Runtime runtime;
 } Object;
 
diff --git a/source/blender/makesdna/DNA_world_types.h b/source/blender/makesdna/DNA_world_types.h
index 497b99eb04d..88f2e0c9407 100644
--- a/source/blender/makesdna/DNA_world_types.h
+++ b/source/blender/makesdna/DNA_world_types.h
@@ -16,6 +16,7 @@ extern "C" {
 
 struct AnimData;
 struct Ipo;
+struct LightgroupMembership;
 struct bNodeTree;
 
 #ifndef MAX_MTEX
@@ -70,6 +71,9 @@ typedef struct World {
   /* nodes */
   struct bNodeTree *nodetree;
 
+  /* Lightgroup membership information. */
+  struct LightgroupMembership *lightgroup;
+
   /** Runtime. */
   ListBase gpumaterial;
 } World;
diff --git a/source/blender/makesrna/intern/rna_internal.h b/source/blender/makesrna/intern/rna_internal.h
index 84f083cb37a..0df0be07fee 100644
--- a/source/blender/makesrna/intern/rna_internal.h
+++ b/source/blender/makesrna/intern/rna_internal.h
@@ -355,6 +355,10 @@ void rna_ViewLayer_active_aov_index_range(
     PointerRNA *ptr, int *min, int *max, int *softmin, int *softmax);
 int rna_ViewLayer_active_aov_index_get(PointerRNA *ptr);
 void rna_ViewLayer_active_aov_index_set(PointerRNA *ptr, int value);
+void rna_ViewLayer_active_lightgroup_index_range(
+    PointerRNA *ptr, int *min, int *max, int *softmin, int *softmax);
+int rna_ViewLayer_active_lightgroup_index_get(PointerRNA *ptr);
+void rna_ViewLayer_active_lightgroup_index_set(PointerRNA *ptr, int value);
 /**
  *  Set `r_rna_path` with the base view-layer path.
  *  `rna_path_buffer_size` should be at least `sizeof(ViewLayer.name) * 3`.
diff --git a/source/blender/makesrna/intern/rna_object.c b/source/blender/makesrna/intern/rna_object.c
index e4495df36f1..f995ee3383e 100644
--- a/source/blender/makesrna/intern/rna_object.c
+++ b/source/blender/makesrna/intern/rna_object.c
@@ -2292,6 +2292,21 @@ static int rna_Object_mesh_symmetry_yz_editable(PointerRNA *ptr, const char **UN
   return PROP_EDITABLE;
 }
 
+void rna_Object_lightgroup_get(PointerRNA *ptr, char *value)
+{
+  BKE_lightgroup_membership_get(((Object *)ptr->owner_id)->lightgroup, value);
+}
+
+int rna_Object_lightgroup_length(PointerRNA *ptr)
+{
+  return BKE_lightgroup_membership_length(((Object *)ptr->owner_id)->lightgroup);
+}
+
+void rna_Object_lightgroup_set(PointerRNA *ptr, const char *value)
+{
+  BKE_lightgroup_membership_set(&((Object *)ptr->owner_id)->lightgroup, value);
+}
+
 #else
 
 static void rna_def_vertex_group(BlenderRNA *brna)
@@ -3775,6 +3790,15 @@ static void rna_def_object(BlenderRNA *brna)
   RNA_def_property_editable_func(prop, "rna_Object_mesh_symmetry_yz_editable");
   RNA_def_property_ui_text(prop, "Z", "Enable mesh symmetry in the Z axis");
 
+  /* Lightgroup Membership */
+  prop = RNA_def_property(srna, "lightgroup", PROP_STRING, PROP_NONE);
+  RNA_def_property_string_funcs(prop,
+                                "rna_Object_lightgroup_get",
+                                "rna_Object_lightgroup_length",
+                                "rna_Object_lightgroup_set");
+  RNA_def_property_flag(prop, PROP_EDITABLE);
+  RNA_def_property_ui_text(prop, "Lightgroup", "Lightgroup that the object belongs to");
+
   RNA_define_lib_overridable(false);
 
   /* anim */
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index 8d5d93e10ac..0960d246257 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -1767,6 +1767,10 @@ void rna_ViewLayer_pass_update(Main *bmain, Scene *activescene, PointerRNA *ptr)
     ViewLayerAOV *aov = (ViewLayerAOV *)ptr->data;
     view_layer = BKE_view_layer_find_with_aov(scene, aov);
   }
+  else if (ptr->type == &RNA_Lightgroup) {
+    ViewLayerLightgroup *lightgroup = (ViewLayerLightgroup *)ptr->data;
+    view_layer = BKE_view_layer_find_with_lightgroup(scene, lightgroup);
+  }
 
   if (view_layer) {
     RenderEngineType *engine_type = RE_engines_find(scene->r.engine);
@@ -2447,6 +2451,49 @@ void rna_ViewLayer_active_aov_index_set(PointerRNA *ptr, int value)
   view_layer->active_aov = aov;
 }
 
+void rna_ViewLayer_active_lightgroup_index_range(
+    PointerRNA *ptr, int *min, int *max, int *UNUSED(softmin), int *UNUSED(softmax))
+{
+  ViewLayer *view_layer = (ViewLayer *)ptr->data;
+
+  *min = 0;
+  *max = max_ii(0, BLI_listbase_count(&view_layer->lightgroups) - 1);
+}
+
+int rna_ViewLayer_active_lightgroup_index_get(PointerRNA *ptr)
+{
+  ViewLayer *view_layer = (ViewLayer *)ptr->data;
+  return BLI_findindex(&view_layer->lightgroups, view_layer->active_lightgroup);
+}
+
+void rna_ViewLayer_active_lightgroup_index_set(PointerRNA *ptr, int value)
+{
+  ViewLayer *view_layer = (ViewLayer *)ptr->data;
+  ViewLayerLightgroup *lightgroup = BLI_findlink(&view_layer->lightgroups, value);
+  view_layer->active_lightgroup = lightgroup;
+}
+
+static void rna_ViewLayerLightgroup_name_get(PointerRNA *ptr, char *value)
+{
+  ViewLayerLightgroup *lightgroup = (ViewLayerLightgroup *)ptr->data;
+  BLI_strncpy(value, lightgroup->name, sizeof(lightgroup->name));
+}
+
+static int rna_ViewLayerLightgroup_name_length(PointerRNA *ptr)
+{
+  ViewLayerLightgroup *lightgroup = (ViewLayerLightgroup *)ptr->data;
+  return strlen(lightgroup->name);
+}
+
+static void rna_ViewLayerLightgroup_name_set(PointerRNA *ptr, const char *value)
+{
+  ViewLayerLightgroup *lightgroup = (ViewLayerLightgroup *)ptr->data;
+  Scene *scene = (Scene *)ptr->owner_id;
+  ViewLayer *view_layer = BKE_view_layer_find_with_lightgroup(scene, lightgroup);
+
+  BKE_view_layer_rename_lightgroup(view_layer, lightgroup, value);
+}
+
 /* Fake value, used internally (not saved to DNA). */
 #  define V3D_ORIENT_DEFAULT -1
 
@@ -4156,6 +4203,43 @@ static void rna_def_view_layer_aov(BlenderRNA *brna)
   RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_ViewLayer_pass_update");
 }
 
+static void rna_def_view_layer_lightgroups(BlenderRNA *brna, PropertyRNA *cprop)
+{
+  StructRNA *srna;
+  /*  PropertyRNA *prop; */
+
+  FunctionRNA *func;
+  PropertyRNA *parm;
+
+  RNA_def_property_srna(cprop, "Lightgroups");
+  srna = RNA_def_struct(brna, "Lightgroups", NULL);
+  RNA_def_struct_sdna(srna, "ViewLayer");
+  RNA_def_struct_ui_text(srna, "List of Lightgroups", "Collection of Lightgroups");
+
+  func = RNA_def_function(srna, "add", "BKE_view_layer_add_lightgroup");
+  parm = RNA_def_pointer(func, "lightgroup", "Lightgroup", "", "Newly created Lightgroup");
+  RNA_def_function_return(func, parm);
+}
+
+static void rna_def_view_layer_lightgroup(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+  srna = RNA_def_struct(brna, "Lightgroup", NULL);
+  RNA_def_struct_sdna(srna, "ViewLayerLightgroup");
+  RNA_def_struct_ui_text(srna, "Light Group", "");
+
+  prop = RNA_def_property(srna, "name", PROP_STRING, PROP_NONE);
+  RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
+  RNA_def_property_string_funcs(prop,
+                                "rna_ViewLayerLightgroup_name_get",
+                                "rna_ViewLayerLightgroup_name_length",
+                                "rna_ViewLayerLightgroup_name_set");
+  RNA_def_property_ui_text(prop, "Name", "Name of the Lightgroup");
+  RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_ViewLayer_pass_update");
+  RNA_def_struct_name_property(srna, prop);
+}
+
 void rna_def_view_layer_common(BlenderRNA *brna, StructRNA *srna, const bool scene)
 {
   PropertyRNA *prop;
@@ -4226,6 +4310,25 @@ void rna_def_view_layer_common(BlenderRNA *brna, StructRNA *srna, const bool sce
     RNA_def_property_ui_text(prop, "Active AOV Index", "Index of active aov");
     RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
 
+    prop = RNA_def_property(srna, "lightgroups", PROP_COLLECTION, PROP_NONE);
+    RNA_def_property_collection_sdna(prop, NULL, "lightgroups", NULL);
+    RNA_def_property_struct_type(prop, "Lightgroup");
+    RNA_def_property_ui_text(prop, "Light Groups", "");
+    rna_def_view_layer_lightgroups(brna, prop);
+
+    prop = RNA_def_property(srna, "active_lightgroup", PROP_POINTER, PROP_NONE);
+    RNA_def_property_struct_type(prop, "Lightgroup");
+    RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+    RNA_def_property_ui_text(prop, "Light Groups", "Active Lightgroup");
+
+    prop = RNA_def_property(srna, "active_lightgroup_index", PROP_INT, PROP_UNSIGNED);
+    RNA_def_property_int_funcs(prop,
+                               "rna_ViewLayer_active_lightgroup_index_get",
+                               "rna_ViewLayer_active_lightgroup_index_set",
+                               "rna_ViewLayer_active_lightgroup_index_range");
+    RNA_def_property_ui_text(prop, "Active Lightgroup Index", "Index of active lightgroup");
+    RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
     prop = RNA_def_property(srna, "use_pass_cryptomatte_object", PROP_BOOLEAN, PROP_NONE);
     RNA_def_property_boolean_sdna(prop, NULL, "cryptomatte_flag", VIEW_LAYER_CRYPTOMATTE_OBJECT);
     RNA_def_property_ui_text(
@@ -8088,6 +8191,7 @@ void RNA_def_scene(BlenderRNA *brna)
   rna_def_scene_display(brna);
   rna_def_scene_eevee(brna);
   rna_def_view_layer_aov(brna);
+  rna_def_view_layer_lightgroup(brna);
   rna_def_view_layer_eevee(brna);
   rna_def_scene_gpencil(brna);
   RNA_define_animate_sdna(true);
diff --git a/source/blender/makesrna/intern/rna_world.c b/source/blender/makesrna/intern/rna_world.c
index 04008665342..d1049eef2c7 100644
--- a/source/blender/makesrna/intern/rna_world.c
+++ b/source/blender/makesrna/intern/rna_world.c
@@ -22,6 +22,7 @@
 #  include "MEM_guardedalloc.h"
 
 #  include "BKE_context.h"
+#  include "BKE_layer.h"
 #  include "BKE_main.h"
 #  include "BKE_texture.h"
 
@@ -84,6 +85,21 @@ static void rna_World_use_nodes_update(bContext *C, PointerRNA *ptr)
   rna_World_draw_update(bmain, scene, ptr);
 }
 
+void rna_World_lightgroup_get(PointerRNA *ptr, char *value)
+{
+  BKE_lightgroup_membership_get(((World *)ptr->owner_id)->lightgroup, value);
+}
+
+int rna_World_lightgroup_length(PointerRNA *ptr)
+{
+  return BKE_lightgroup_membership_length(((World *)ptr->owner_id)->lightgroup);
+}
+
+void rna_World_lightgroup_set(PointerRNA *ptr, const char *value)
+{
+  BKE_lightgroup_membership_set(&((World *)ptr->owner_id)->lightgroup, value);
+}
+
 #else
 
 static void rna_def_lighting(BlenderRNA *brna)
@@ -234,6 +250,13 @@ void RNA_def_world(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Use Nodes", "Use shader nodes to render the world");
   RNA_def_property_update(prop, 0, "rna_World_use_nodes_update");
 
+  /* Lightgroup Membership */
+  prop = RNA_def_property(srna, "lightgroup", PROP_STRING, PROP_NONE);
+  RNA_def_property_string_funcs(
+      prop, "rna_World_lightgroup_get", "rna_World_lightgroup_length", "rna_World_lightgroup_set");
+  RNA_def_property_flag(prop, PROP_EDITABLE);
+  RNA_def_property_ui_text(prop, "Lightgroup", "Lightgroup that the world belongs to");
+
   rna_def_lighting(brna);
   rna_def_world_mist(brna);
 }