From be2bc97eba499c48e3856c8e5ec4d869e28b4d04 Mon Sep 17 00:00:00 2001
From: Jeroen Bakker <jbakker>
Date: Thu, 20 Feb 2020 14:53:53 +0100
Subject: EEVEE: Render Passes
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This patch adds new render passes to EEVEE. These passes include:

* Emission
* Diffuse Light
* Diffuse Color
* Glossy Light
* Glossy Color
* Environment
* Volume Scattering
* Volume Transmission
* Bloom
* Shadow

With these passes it will be possible to use EEVEE effectively for
compositing. During development we kept a close eye on how to get similar
results compared to cycles render passes there are some differences that
are related to how EEVEE works. For EEVEE we combined the passes to
`Diffuse` and `Specular`. There are no transmittance or sss passes anymore.
Cycles will be changed accordingly.

Cycles volume transmittance is added to multiple surface col passes. For
EEVEE we left the volume transmittance as a separate pass.

Known Limitations

* All materials that use alpha blending will not be rendered in the render
  passes. Other transparency modes are supported.
* More GPU memory is required to store the render passes. When rendering
  a HD image with all render passes enabled at max extra 570MB GPU memory is
  required.

Implementation Details

An overview of render passes have been described in
https://wiki.blender.org/wiki/Source/Render/EEVEE/RenderPasses

Future Developments

* In this implementation the materials are re-rendered for Diffuse/Glossy
  and Emission passes. We could use multi target rendering to improve the
  render speed.
* Other passes can be added later
* Don't render material based passes when only requesting AO or Shadow.
* Add more passes to the system. These could include Cryptomatte, AOV's, Vector,
  ObjectID, MaterialID, UV.

Reviewed By: Clément Foucault

Differential Revision: https://developer.blender.org/D6331
---
 source/blender/makesrna/intern/rna_scene.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'source/blender/makesrna/intern/rna_scene.c')

diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index d2a17967de9..32c6239da5a 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -3756,6 +3756,30 @@ static void rna_def_unit_settings(BlenderRNA *brna)
   RNA_def_property_update(prop, NC_WINDOW, NULL);
 }
 
+static void rna_def_view_layer_eevee(BlenderRNA *brna)
+{
+  StructRNA *srna;
+  PropertyRNA *prop;
+  srna = RNA_def_struct(brna, "ViewLayerEEVEE", NULL);
+  RNA_def_struct_ui_text(srna, "EEVEE Settings", "View layer settings for EEVEE");
+
+  prop = RNA_def_property(srna, "use_pass_volume_scatter", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "render_passes", EEVEE_RENDER_PASS_VOLUME_SCATTER);
+  RNA_def_property_ui_text(prop, "Volume Scatter", "Deliver volume scattering pass");
+  RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_ViewLayer_pass_update");
+
+  prop = RNA_def_property(srna, "use_pass_volume_transmittance", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(
+      prop, NULL, "render_passes", EEVEE_RENDER_PASS_VOLUME_TRANSMITTANCE);
+  RNA_def_property_ui_text(prop, "Volume Transmittance", "Deliver volume transmittance pass");
+  RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_ViewLayer_pass_update");
+
+  prop = RNA_def_property(srna, "use_pass_bloom", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "render_passes", EEVEE_RENDER_PASS_BLOOM);
+  RNA_def_property_ui_text(prop, "Bloom", "Deliver bloom pass");
+  RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_ViewLayer_pass_update");
+}
+
 void rna_def_view_layer_common(StructRNA *srna, const bool scene)
 {
   PropertyRNA *prop;
@@ -3801,6 +3825,11 @@ void rna_def_view_layer_common(StructRNA *srna, const bool scene)
         "Z, Index, normal, UV and vector passes are only affected by surfaces with "
         "alpha transparency equal to or higher than this threshold");
     RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
+    prop = RNA_def_property(srna, "eevee", PROP_POINTER, PROP_NONE);
+    RNA_def_property_flag(prop, PROP_NEVER_NULL);
+    RNA_def_property_struct_type(prop, "ViewLayerEEVEE");
+    RNA_def_property_ui_text(prop, "EEVEE Settings", "View layer settings for EEVEE");
   }
 
   /* layer options */
@@ -7546,6 +7575,7 @@ void RNA_def_scene(BlenderRNA *brna)
   rna_def_display_safe_areas(brna);
   rna_def_scene_display(brna);
   rna_def_scene_eevee(brna);
+  rna_def_view_layer_eevee(brna);
   RNA_define_animate_sdna(true);
   /* *** Animated *** */
   rna_def_scene_render_data(brna);
-- 
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