7 files changed, 57 insertions, 6 deletions

diff --git a/release/scripts/startup/bl_ui/space_image.py b/release/scripts/startup/bl_ui/space_image.py
index dcb0ab2e9e5..3ee668888f3 100644
--- a/release/scripts/startup/bl_ui/space_image.py
+++ b/release/scripts/startup/bl_ui/space_image.py
@@ -1453,7 +1453,7 @@ class IMAGE_PT_udim_grid(Panel):
     def poll(cls, context):
         sima = context.space_data
 
-        return sima.show_uvedit and sima.image is None
+        return sima.show_uvedit
 
     def draw(self, context):
         layout = self.layout
diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index 8bf74dae7f8..71115c5ceb9 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -447,6 +447,7 @@ data_to_c_simple(engines/overlay/shaders/extra_wire_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/extra_wire_vert.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/facing_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/facing_vert.glsl SRC)
+data_to_c_simple(engines/overlay/shaders/grid_background_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/grid_frag.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/grid_vert.glsl SRC)
 data_to_c_simple(engines/overlay/shaders/image_vert.glsl SRC)
diff --git a/source/blender/draw/engines/overlay/overlay_grid.c b/source/blender/draw/engines/overlay/overlay_grid.c
index 5bb157ed081..60cda9f2d61 100644
--- a/source/blender/draw/engines/overlay/overlay_grid.c
+++ b/source/blender/draw/engines/overlay/overlay_grid.c
@@ -61,10 +61,19 @@ void OVERLAY_grid_init(OVERLAY_Data *vedata)
 
   if (pd->space_type == SPACE_IMAGE) {
     SpaceImage *sima = (SpaceImage *)draw_ctx->space_data;
-    shd->grid_flag = ED_space_image_has_buffer(sima) ? 0 : PLANE_IMAGE | SHOW_GRID;
+    if (sima->mode == SI_MODE_UV || !ED_space_image_has_buffer(sima)) {
+      shd->grid_flag = GRID_BACK | PLANE_IMAGE | SHOW_GRID;
+    }
+    else {
+      shd->grid_flag = 0;
+    }
+
     shd->grid_distance = 1.0f;
-    copy_v3_fl3(
-        shd->grid_size, (float)sima->tile_grid_shape[0], (float)sima->tile_grid_shape[1], 1.0f);
+    copy_v3_fl3(shd->grid_size, 1.0f, 1.0f, 1.0f);
+    if (sima->mode == SI_MODE_UV) {
+      shd->grid_size[0] = (float)sima->tile_grid_shape[0];
+      shd->grid_size[1] = (float)sima->tile_grid_shape[1];
+    }
     for (int step = 0; step < 8; step++) {
       shd->grid_steps[step] = powf(4, step) * (1.0f / 16.0f);
     }
@@ -209,11 +218,12 @@ void OVERLAY_grid_cache_init(OVERLAY_Data *vedata)
     float mat[4][4];
 
     /* add quad background */
-    sh = OVERLAY_shader_grid_image();
+    sh = OVERLAY_shader_grid_background();
     grp = DRW_shgroup_create(sh, psl->grid_ps);
     float color_back[4];
     interp_v4_v4v4(color_back, G_draw.block.colorBackground, G_draw.block.colorGrid, 0.5);
     DRW_shgroup_uniform_vec4_copy(grp, "color", color_back);
+    DRW_shgroup_uniform_texture_ref(grp, "depthBuffer", &dtxl->depth);
     unit_m4(mat);
     mat[0][0] = shd->grid_size[0];
     mat[1][1] = shd->grid_size[1];
diff --git a/source/blender/draw/engines/overlay/overlay_private.h b/source/blender/draw/engines/overlay/overlay_private.h
index 68f60bee779..23df571e8de 100644
--- a/source/blender/draw/engines/overlay/overlay_private.h
+++ b/source/blender/draw/engines/overlay/overlay_private.h
@@ -722,6 +722,7 @@ GPUShader *OVERLAY_shader_extra_point(void);
 GPUShader *OVERLAY_shader_facing(void);
 GPUShader *OVERLAY_shader_gpencil_canvas(void);
 GPUShader *OVERLAY_shader_grid(void);
+GPUShader *OVERLAY_shader_grid_background(void);
 GPUShader *OVERLAY_shader_grid_image(void);
 GPUShader *OVERLAY_shader_image(void);
 GPUShader *OVERLAY_shader_motion_path_line(void);
diff --git a/source/blender/draw/engines/overlay/overlay_shader.c b/source/blender/draw/engines/overlay/overlay_shader.c
index edf9148c8c0..389704b3d66 100644
--- a/source/blender/draw/engines/overlay/overlay_shader.c
+++ b/source/blender/draw/engines/overlay/overlay_shader.c
@@ -91,6 +91,7 @@ extern char datatoc_extra_wire_frag_glsl[];
 extern char datatoc_extra_wire_vert_glsl[];
 extern char datatoc_facing_frag_glsl[];
 extern char datatoc_facing_vert_glsl[];
+extern char datatoc_grid_background_frag_glsl[];
 extern char datatoc_grid_frag_glsl[];
 extern char datatoc_grid_vert_glsl[];
 extern char datatoc_image_frag_glsl[];
@@ -198,6 +199,7 @@ typedef struct OVERLAY_Shaders {
   GPUShader *facing;
   GPUShader *gpencil_canvas;
   GPUShader *grid;
+  GPUShader *grid_background;
   GPUShader *grid_image;
   GPUShader *image;
   GPUShader *motion_path_line;
@@ -1053,6 +1055,20 @@ GPUShader *OVERLAY_shader_grid(void)
   return sh_data->grid;
 }
 
+GPUShader *OVERLAY_shader_grid_background(void)
+{
+  OVERLAY_Shaders *sh_data = &e_data.sh_data[0];
+  if (!sh_data->grid_background) {
+    sh_data->grid_background = GPU_shader_create_from_arrays({
+        .vert = (const char *[]){datatoc_common_view_lib_glsl,
+                                 datatoc_edit_uv_tiled_image_borders_vert_glsl,
+                                 NULL},
+        .frag = (const char *[]){datatoc_grid_background_frag_glsl, NULL},
+    });
+  }
+  return sh_data->grid_background;
+}
+
 GPUShader *OVERLAY_shader_grid_image(void)
 {
   OVERLAY_Shaders *sh_data = &e_data.sh_data[0];
diff --git a/source/blender/draw/engines/overlay/shaders/grid_background_frag.glsl b/source/blender/draw/engines/overlay/shaders/grid_background_frag.glsl
new file mode 100644
index 00000000000..fcc05414ea3
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/grid_background_frag.glsl
@@ -0,0 +1,12 @@
+
+uniform vec4 color;
+uniform sampler2D depthBuffer;
+
+out vec4 fragColor;
+
+void main()
+{
+    fragColor = color;
+    float scene_depth = texelFetch(depthBuffer, ivec2(gl_FragCoord.xy), 0).r;
+    fragColor.a = (scene_depth == 1.0) ? 1.0 : 0.0;
+}
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index d391b09189a..7aee6944d8d 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -1796,6 +1796,16 @@ static const EnumPropertyItem *rna_SpaceImageEditor_pivot_itemf(bContext *UNUSED
   }
 }
 
+static void rna_SpaceUVEditor_tile_grid_shape_set(PointerRNA *ptr, const int *values)
+{
+  SpaceImage *data = (SpaceImage *)(ptr->data);
+
+  int clamp[2] = {10, 100};
+  for (int i = 0; i < 2; i++) {
+    data->tile_grid_shape[i] = CLAMPIS(values[i], 1, clamp[i]);
+  }
+}
+
 /* Space Text Editor */
 
 static void rna_SpaceTextEditor_word_wrap_set(PointerRNA *ptr, bool value)
@@ -3417,7 +3427,8 @@ static void rna_def_space_image_uv(BlenderRNA *brna)
   RNA_def_property_int_sdna(prop, NULL, "tile_grid_shape");
   RNA_def_property_array(prop, 2);
   RNA_def_property_int_default(prop, 1);
-  RNA_def_property_range(prop, 1, 10);
+  RNA_def_property_range(prop, 1, 100);
+  RNA_def_property_int_funcs(prop, NULL, "rna_SpaceUVEditor_tile_grid_shape_set", NULL);
   RNA_def_property_ui_text(
       prop, "Tile Grid Shape", "How many tiles will be shown in the background");
   RNA_def_property_update(prop, NC_SPACE | ND_SPACE_IMAGE, NULL);