Cycles: Display RenderPass in Viewport

This change allows the user to select a renderpass in the 3d viewport.

Added support for external renderers to extend the `View3DShading` struct.
This way Blender doesn't need to know the features an external render engine wants to support.
Note that the View3DShading is also available in the scene->display.shading; although this is
supported, it does not make sense for render engines to put something here as it is really
scene/workbench related.

Currently cycles assumes that it always needs to calculate the combined pass; it ignores the
`pass_flag` in KernelFilm. We could optimize this but that was not in scope of this change

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D5689

2 files changed, 74 insertions, 0 deletions

diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py
index 3acdfc391a6..93f8f76cd6a 100644
--- a/intern/cycles/blender/addon/properties.py
+++ b/intern/cycles/blender/addon/properties.py
@@ -151,6 +151,44 @@ enum_texture_limit = (
     ('8192', "8192", "Limit texture size to 8192 pixels", 7),
 )
 
+enum_view3d_shading_render_pass= (
+    ('', "General", ""),
+
+    ('COMBINED', "Combined", "Show the Combined Render pass", 1),
+    ('EMISSION', "Emission", "Show the Emission render pass", 33),
+    ('BACKGROUND', "Background", "Show the Background render pass", 34),
+    ('AO', "Ambient Occlusion", "Show the Ambient Occlusion render pass", 35),
+
+    ('', "Light", ""),
+
+    ('DIFFUSE_DIRECT', "Diffuse Direct", "Show the Diffuse Direct render pass", 38),
+    ('DIFFUSE_INDIRECT', "Diffuse Indirect", "Show the Diffuse Indirect render pass", 39),
+    ('DIFFUSE_COLOR', "Diffuse Color", "Show the Diffuse Color render pass", 40),
+
+    ('GLOSSY_DIRECT', "Glossy Direct", "Show the Glossy Direct render pass", 41),
+    ('GLOSSY_INDIRECT', "Glossy Indirect", "Show the Glossy Indirect render pass", 42),
+    ('GLOSSY_COLOR', "Glossy Color", "Show the Glossy Color render pass", 43),
+
+    ('', "", ""),
+
+    ('TRANSMISSION_DIRECT', "Transmission Direct", "Show the Transmission Direct render pass", 44),
+    ('TRANSMISSION_INDIRECT', "Transmission Indirect", "Show the Transmission Indirect render pass", 45),
+    ('TRANSMISSION_COLOR', "Transmission Color", "Show the Transmission Color render pass", 46),
+
+    ('SUBSURFACE_DIRECT', "Subsurface Direct", "Show the Subsurface Direct render pass", 47),
+    ('SUBSURFACE_INDIRECT', "Subsurface Indirect", "Show the Subsurface Indirect render pass", 48),
+    ('SUBSURFACE_COLOR', "Subsurface Color", "Show the Subsurface Color render pass", 49),
+
+    ('VOLUME_DIRECT', "Volume Direct", "Show the Volume Direct render pass", 50),
+    ('VOLUME_INDIRECT', "Volume Indirect", "Show the Volume Indirect render pass", 51),
+
+    ('', "Data", ""),
+
+    ('NORMAL', "Normal", "Show the Normal render pass", 3),
+    ('UV', "UV", "Show the UV render pass", 4),
+    ('MIST', "Mist", "Show the Mist render pass", 32),
+)
+
 
 class CyclesRenderSettings(bpy.types.PropertyGroup):
 
@@ -1475,6 +1513,15 @@ class CyclesPreferences(bpy.types.AddonPreferences):
         self.draw_impl(self.layout, context)
 
 
+class CyclesView3DShadingSettings(bpy.types.PropertyGroup):
+    render_pass: EnumProperty(
+        name="Render Pass",
+        description="Render pass to show in the 3D Viewport",
+        items=enum_view3d_shading_render_pass,
+        default='COMBINED',
+    )
+
+
 def register():
     bpy.utils.register_class(CyclesRenderSettings)
     bpy.utils.register_class(CyclesCameraSettings)
@@ -1488,6 +1535,12 @@ def register():
     bpy.utils.register_class(CyclesDeviceSettings)
     bpy.utils.register_class(CyclesPreferences)
     bpy.utils.register_class(CyclesRenderLayerSettings)
+    bpy.utils.register_class(CyclesView3DShadingSettings)
+
+    bpy.types.View3DShading.cycles = bpy.props.PointerProperty(
+        name="Cycles Settings",
+        type=CyclesView3DShadingSettings,
+    )
 
 
 def unregister():
@@ -1503,3 +1556,4 @@ def unregister():
     bpy.utils.unregister_class(CyclesDeviceSettings)
     bpy.utils.unregister_class(CyclesPreferences)
     bpy.utils.unregister_class(CyclesRenderLayerSettings)
+    bpy.utils.unregister_class(CyclesView3DShadingSettings)
diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py
index 0af59411c5c..9028100ad7a 100644
--- a/intern/cycles/blender/addon/ui.py
+++ b/intern/cycles/blender/addon/ui.py
@@ -2050,6 +2050,25 @@ class CYCLES_RENDER_PT_simplify_culling(CyclesButtonsPanel, Panel):
         sub.prop(cscene, "distance_cull_margin", text="Distance")
 
 
+class CYCLES_VIEW3D_PT_shading_render_pass(Panel):
+    bl_space_type = 'VIEW_3D'
+    bl_region_type = 'HEADER'
+    bl_label = "Render Pass"
+    bl_parent_id = 'VIEW3D_PT_shading'
+    COMPAT_ENGINES = {'CYCLES'}
+
+    @classmethod
+    def poll(cls, context):
+        return (context.engine in cls.COMPAT_ENGINES
+            and context.space_data.shading.type == 'RENDERED')
+
+    def draw(self, context):
+        shading = context.space_data.shading
+
+        layout = self.layout
+        layout.prop(shading.cycles, "render_pass", text="")
+
+
 class CYCLES_VIEW3D_PT_shading_lighting(Panel):
     bl_space_type = 'VIEW_3D'
     bl_region_type = 'HEADER'
@@ -2172,6 +2191,7 @@ classes = (
     CYCLES_RENDER_PT_simplify_render,
     CYCLES_RENDER_PT_simplify_culling,
     CYCLES_VIEW3D_PT_shading_lighting,
+    CYCLES_VIEW3D_PT_shading_render_pass,
     CYCLES_RENDER_PT_motion_blur,
     CYCLES_RENDER_PT_motion_blur_curve,
     CYCLES_RENDER_PT_film,