Eevee: Add Volume Transmittance to Color Render Passes.

In Cycles the volume transmittance is already composited into the color
passes. In Eevee the volume transmittance pass was separate and needed
to be composited in the compositor. This patch adds the volume
transmittance pass direct in the next render passes:

 * Diffuse Color
 * Specular Color
 * Emission
 * Environment

This patch includes the removal of the volume transmittance render pass.
It also renames the volume render passes to match Cycles. The setting
themselves aren't unified.

Maniphest Tasks: T81134

1 files changed, 8 insertions, 18 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_render.c b/source/blender/draw/engines/eevee/eevee_render.c
index 2b2ff2e5c90..2a01aeefce8 100644
--- a/source/blender/draw/engines/eevee/eevee_render.c
+++ b/source/blender/draw/engines/eevee/eevee_render.c
@@ -461,21 +461,13 @@ static void eevee_render_result_environment(RenderLayer *rl,
   EEVEE_RENDER_RESULT_MATERIAL_PASS(ENVIRONMENT, ENVIRONMENT)
 }
 
-static void eevee_render_result_volume_scatter(RenderLayer *rl,
-                                               const char *viewname,
-                                               const rcti *rect,
-                                               EEVEE_Data *vedata,
-                                               EEVEE_ViewLayerData *sldata)
-{
-  EEVEE_RENDER_RESULT_MATERIAL_PASS(VOLUME_SCATTER, VOLUME_SCATTER)
-}
-static void eevee_render_result_volume_transmittance(RenderLayer *rl,
-                                                     const char *viewname,
-                                                     const rcti *rect,
-                                                     EEVEE_Data *vedata,
-                                                     EEVEE_ViewLayerData *sldata)
+static void eevee_render_result_volume_light(RenderLayer *rl,
+                                             const char *viewname,
+                                             const rcti *rect,
+                                             EEVEE_Data *vedata,
+                                             EEVEE_ViewLayerData *sldata)
 {
-  EEVEE_RENDER_RESULT_MATERIAL_PASS(VOLUME_TRANSMITTANCE, VOLUME_TRANSMITTANCE)
+  EEVEE_RENDER_RESULT_MATERIAL_PASS(VOLUME_LIGHT, VOLUME_LIGHT)
 }
 
 static void eevee_render_result_aovs(RenderLayer *rl,
@@ -696,8 +688,7 @@ void EEVEE_render_read_result(EEVEE_Data *vedata,
   eevee_render_result_emission(rl, viewname, rect, vedata, sldata);
   eevee_render_result_environment(rl, viewname, rect, vedata, sldata);
   eevee_render_result_bloom(rl, viewname, rect, vedata, sldata);
-  eevee_render_result_volume_scatter(rl, viewname, rect, vedata, sldata);
-  eevee_render_result_volume_transmittance(rl, viewname, rect, vedata, sldata);
+  eevee_render_result_volume_light(rl, viewname, rect, vedata, sldata);
   eevee_render_result_aovs(rl, viewname, rect, vedata, sldata);
   eevee_render_result_cryptomatte(rl, viewname, rect, vedata, sldata);
 }
@@ -730,8 +721,7 @@ void EEVEE_render_update_passes(RenderEngine *engine, Scene *scene, ViewLayer *v
   CHECK_PASS_LEGACY(GLOSSY_DIRECT, SOCK_RGBA, 3, "RGB");
   CHECK_PASS_LEGACY(EMIT, SOCK_RGBA, 3, "RGB");
   CHECK_PASS_LEGACY(ENVIRONMENT, SOCK_RGBA, 3, "RGB");
-  CHECK_PASS_EEVEE(VOLUME_SCATTER, SOCK_RGBA, 3, "RGB");
-  CHECK_PASS_EEVEE(VOLUME_TRANSMITTANCE, SOCK_RGBA, 3, "RGB");
+  CHECK_PASS_EEVEE(VOLUME_LIGHT, SOCK_RGBA, 3, "RGB");
   CHECK_PASS_EEVEE(BLOOM, SOCK_RGBA, 3, "RGB");
 
   LISTBASE_FOREACH (ViewLayerAOV *, aov, &view_layer->aovs) {