Revert "EEVEE: Fix volumetric resolve in large scenes."

This reverts commit 34051fcc12f388375697dcfc6da53e9909058fe1.
Although for normal use this doesn't make a difference. But when working with
huge scenes and volumetrics + NVIDIA it made a work-around not possible anymore.

For the heist production we added a fix on the render-farm (enable GPU workarounds).
{rB34051fcc12f388375697dcfc6da53e9909058fe1} made another work-around not
accessible anymore and it and was requested to revert this change.

8 files changed, 15 insertions, 113 deletions

diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index e6b532ed25a..32103692421 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -388,7 +388,6 @@ set(GLSL_SRC
   engines/eevee/shaders/volumetric_frag.glsl
   engines/eevee/shaders/volumetric_geom.glsl
   engines/eevee/shaders/volumetric_vert.glsl
-  engines/eevee/shaders/volumetric_resolve_comp.glsl
   engines/eevee/shaders/volumetric_resolve_frag.glsl
   engines/eevee/shaders/volumetric_scatter_frag.glsl
   engines/eevee/shaders/volumetric_integration_frag.glsl
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index 94a0154055c..88e56bdc01c 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -1261,7 +1261,6 @@ struct GPUShader *EEVEE_shaders_volumes_scatter_sh_get(void);
 struct GPUShader *EEVEE_shaders_volumes_scatter_with_lights_sh_get(void);
 struct GPUShader *EEVEE_shaders_volumes_integration_sh_get(void);
 struct GPUShader *EEVEE_shaders_volumes_resolve_sh_get(bool accum);
-struct GPUShader *EEVEE_shaders_volumes_resolve_comp_sh_get(bool float_target);
 struct GPUShader *EEVEE_shaders_volumes_accum_sh_get(void);
 struct GPUShader *EEVEE_shaders_ggx_lut_sh_get(void);
 struct GPUShader *EEVEE_shaders_ggx_refraction_lut_sh_get(void);
diff --git a/source/blender/draw/engines/eevee/eevee_shaders.c b/source/blender/draw/engines/eevee/eevee_shaders.c
index a7290b3894e..04d1168a30d 100644
--- a/source/blender/draw/engines/eevee/eevee_shaders.c
+++ b/source/blender/draw/engines/eevee/eevee_shaders.c
@@ -133,7 +133,6 @@ static struct {
   struct GPUShader *scatter_with_lights_sh;
   struct GPUShader *volumetric_integration_sh;
   struct GPUShader *volumetric_resolve_sh[2];
-  struct GPUShader *volumetric_resolve_comp_sh[2];
   struct GPUShader *volumetric_accum_sh;
 
   /* Shader strings */
@@ -262,7 +261,6 @@ extern char datatoc_volumetric_frag_glsl[];
 extern char datatoc_volumetric_geom_glsl[];
 extern char datatoc_volumetric_integration_frag_glsl[];
 extern char datatoc_volumetric_lib_glsl[];
-extern char datatoc_volumetric_resolve_comp_glsl[];
 extern char datatoc_volumetric_resolve_frag_glsl[];
 extern char datatoc_volumetric_scatter_frag_glsl[];
 extern char datatoc_volumetric_vert_glsl[];
@@ -905,20 +903,6 @@ struct GPUShader *EEVEE_shaders_volumes_resolve_sh_get(bool accum)
   return e_data.volumetric_resolve_sh[index];
 }
 
-struct GPUShader *EEVEE_shaders_volumes_resolve_comp_sh_get(bool float_target)
-{
-  const int index = (float_target ? 1 : 0);
-  if (e_data.volumetric_resolve_comp_sh[index] == NULL) {
-    e_data.volumetric_resolve_comp_sh[index] = DRW_shader_create_compute_with_shaderlib(
-        datatoc_volumetric_resolve_comp_glsl,
-        e_data.lib,
-        float_target ? "#define TARGET_IMG_FLOAT\n" SHADER_DEFINES : SHADER_DEFINES,
-        __func__);
-  }
-
-  return e_data.volumetric_resolve_comp_sh[index];
-}
-
 struct GPUShader *EEVEE_shaders_volumes_accum_sh_get()
 {
   if (e_data.volumetric_accum_sh == NULL) {
diff --git a/source/blender/draw/engines/eevee/eevee_volumes.c b/source/blender/draw/engines/eevee/eevee_volumes.c
index b2e5a0abe94..2d96cffb4ba 100644
--- a/source/blender/draw/engines/eevee/eevee_volumes.c
+++ b/source/blender/draw/engines/eevee/eevee_volumes.c
@@ -396,37 +396,18 @@ void EEVEE_volumes_cache_finish(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata)
         grp, NULL, USE_VOLUME_OPTI ? 1 : common_data->vol_tex_size[2]);
 
     DRW_PASS_CREATE(psl->volumetric_resolve_ps, DRW_STATE_WRITE_COLOR | DRW_STATE_BLEND_CUSTOM);
-    if (GPU_compute_shader_support() && GPU_shader_image_load_store_support()) {
-      const bool use_float_target = DRW_state_is_image_render();
-      grp = DRW_shgroup_create(EEVEE_shaders_volumes_resolve_comp_sh_get(use_float_target),
-                               psl->volumetric_resolve_ps);
-      DRW_shgroup_uniform_texture_ref(grp, "inScattering", &txl->volume_scatter);
-      DRW_shgroup_uniform_texture_ref(grp, "inTransmittance", &txl->volume_transmit);
-      DRW_shgroup_uniform_texture_ref(grp, "inSceneDepth", &e_data.depth_src);
-      DRW_shgroup_uniform_block(grp, "light_block", sldata->light_ubo);
-      DRW_shgroup_uniform_block(grp, "common_block", sldata->common_ubo);
-      DRW_shgroup_uniform_block(grp, "probe_block", sldata->probe_ubo);
-      DRW_shgroup_uniform_block(grp, "renderpass_block", sldata->renderpass_ubo.combined);
-      DRW_shgroup_uniform_block(grp, "shadow_block", sldata->shadow_ubo);
-      DRW_shgroup_uniform_image_ref(grp, "target_img", &txl->color);
-
-      const float *size = DRW_viewport_size_get();
-      DRW_shgroup_call_compute(grp, size[0], size[1], 1);
-    }
-    else {
-      grp = DRW_shgroup_create(EEVEE_shaders_volumes_resolve_sh_get(false),
-                               psl->volumetric_resolve_ps);
-      DRW_shgroup_uniform_texture_ref(grp, "inScattering", &txl->volume_scatter);
-      DRW_shgroup_uniform_texture_ref(grp, "inTransmittance", &txl->volume_transmit);
-      DRW_shgroup_uniform_texture_ref(grp, "inSceneDepth", &e_data.depth_src);
-      DRW_shgroup_uniform_block(grp, "light_block", sldata->light_ubo);
-      DRW_shgroup_uniform_block(grp, "common_block", sldata->common_ubo);
-      DRW_shgroup_uniform_block(grp, "probe_block", sldata->probe_ubo);
-      DRW_shgroup_uniform_block(grp, "renderpass_block", sldata->renderpass_ubo.combined);
-      DRW_shgroup_uniform_block(grp, "shadow_block", sldata->shadow_ubo);
+    grp = DRW_shgroup_create(EEVEE_shaders_volumes_resolve_sh_get(false),
+                             psl->volumetric_resolve_ps);
+    DRW_shgroup_uniform_texture_ref(grp, "inScattering", &txl->volume_scatter);
+    DRW_shgroup_uniform_texture_ref(grp, "inTransmittance", &txl->volume_transmit);
+    DRW_shgroup_uniform_texture_ref(grp, "inSceneDepth", &e_data.depth_src);
+    DRW_shgroup_uniform_block(grp, "light_block", sldata->light_ubo);
+    DRW_shgroup_uniform_block(grp, "common_block", sldata->common_ubo);
+    DRW_shgroup_uniform_block(grp, "probe_block", sldata->probe_ubo);
+    DRW_shgroup_uniform_block(grp, "renderpass_block", sldata->renderpass_ubo.combined);
+    DRW_shgroup_uniform_block(grp, "shadow_block", sldata->shadow_ubo);
 
-      DRW_shgroup_call_procedural_triangles(grp, NULL, 1);
-    }
+    DRW_shgroup_call_procedural_triangles(grp, NULL, 1);
   }
 }
 
@@ -565,16 +546,11 @@ void EEVEE_volumes_resolve(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *veda
     }
 
     /* Apply for opaque geometry. */
-    if (GPU_compute_shader_support() && GPU_shader_image_load_store_support()) {
-      DRW_draw_pass(psl->volumetric_resolve_ps);
-    }
-    else {
-      GPU_framebuffer_bind(fbl->main_color_fb);
-      DRW_draw_pass(psl->volumetric_resolve_ps);
+    GPU_framebuffer_bind(fbl->main_color_fb);
+    DRW_draw_pass(psl->volumetric_resolve_ps);
 
-      /* Restore. */
-      GPU_framebuffer_bind(fbl->main_fb);
-    }
+    /* Restore. */
+    GPU_framebuffer_bind(fbl->main_fb);
   }
 }
 
diff --git a/source/blender/draw/engines/eevee/shaders/volumetric_resolve_comp.glsl b/source/blender/draw/engines/eevee/shaders/volumetric_resolve_comp.glsl
deleted file mode 100644
index 2b0139ff923..00000000000
--- a/source/blender/draw/engines/eevee/shaders/volumetric_resolve_comp.glsl
+++ /dev/null
@@ -1,38 +0,0 @@
-
-#pragma BLENDER_REQUIRE(volumetric_lib.glsl)
-
-/* Based on Frosbite Unified Volumetric.
- * https://www.ea.com/frostbite/news/physically-based-unified-volumetric-rendering-in-frostbite */
-
-/* Step 4 : Apply final integration on top of the scene color. */
-
-uniform sampler2D inSceneDepth;
-
-layout(local_size_x = 1, local_size_y = 1) in;
-
-#ifdef TARGET_IMG_FLOAT
-layout(binding = 0, rgba32f) uniform image2D target_img;
-#else
-layout(binding = 0, rgba16f) uniform image2D target_img;
-#endif
-
-void main()
-{
-  ivec2 co = ivec2(gl_GlobalInvocationID.xy);
-  vec2 uvs = co / vec2(textureSize(inSceneDepth, 0));
-  float scene_depth = texture(inSceneDepth, uvs).r;
-
-  vec3 transmittance, scattering;
-  volumetric_resolve(uvs, scene_depth, transmittance, scattering);
-
-  /* Approximate volume alpha by using a monochromatic transmittance
-   * and adding it to the scene alpha. */
-  float alpha = dot(transmittance, vec3(1.0 / 3.0));
-
-  vec4 color0 = vec4(scattering, 1.0 - alpha);
-  vec4 color1 = vec4(transmittance, alpha);
-
-  vec4 color_in = imageLoad(target_img, co);
-  vec4 color_out = color0 + color1 * color_in;
-  imageStore(target_img, co, color_out);
-}
diff --git a/source/blender/draw/intern/DRW_render.h b/source/blender/draw/intern/DRW_render.h
index b49203d85f6..7b80ffd2b88 100644
--- a/source/blender/draw/intern/DRW_render.h
+++ b/source/blender/draw/intern/DRW_render.h
@@ -207,10 +207,6 @@ struct GPUShader *DRW_shader_create_with_lib_ex(const char *vert,
                                                 const char *lib,
                                                 const char *defines,
                                                 const char *name);
-struct GPUShader *DRW_shader_create_compute_with_shaderlib(const char *comp,
-                                                           const DRWShaderLibrary *lib,
-                                                           const char *defines,
-                                                           const char *name);
 struct GPUShader *DRW_shader_create_with_shaderlib_ex(const char *vert,
                                                       const char *geom,
                                                       const char *frag,
diff --git a/source/blender/draw/intern/draw_manager_shader.c b/source/blender/draw/intern/draw_manager_shader.c
index 1ada99093c6..4bc3898c5e7 100644
--- a/source/blender/draw/intern/draw_manager_shader.c
+++ b/source/blender/draw/intern/draw_manager_shader.c
@@ -297,18 +297,6 @@ GPUShader *DRW_shader_create_with_lib_ex(const char *vert,
   return sh;
 }
 
-GPUShader *DRW_shader_create_compute_with_shaderlib(const char *comp,
-                                                    const DRWShaderLibrary *lib,
-                                                    const char *defines,
-                                                    const char *name)
-{
-  char *comp_with_lib = DRW_shader_library_create_shader_string(lib, comp);
-  GPUShader *sh = GPU_shader_create_compute(comp_with_lib, NULL, defines, name);
-  MEM_SAFE_FREE(comp_with_lib);
-
-  return sh;
-}
-
 GPUShader *DRW_shader_create_with_shaderlib_ex(const char *vert,
                                                const char *geom,
                                                const char *frag,
diff --git a/source/blender/draw/tests/shaders_test.cc b/source/blender/draw/tests/shaders_test.cc
index 892fd999fb5..e7baac63aae 100644
--- a/source/blender/draw/tests/shaders_test.cc
+++ b/source/blender/draw/tests/shaders_test.cc
@@ -360,8 +360,6 @@ static void test_eevee_glsl_shaders_static()
   EXPECT_NE(EEVEE_shaders_volumes_integration_sh_get(), nullptr);
   EXPECT_NE(EEVEE_shaders_volumes_resolve_sh_get(false), nullptr);
   EXPECT_NE(EEVEE_shaders_volumes_resolve_sh_get(true), nullptr);
-  EXPECT_NE(EEVEE_shaders_volumes_resolve_comp_sh_get(false), nullptr);
-  EXPECT_NE(EEVEE_shaders_volumes_resolve_comp_sh_get(true), nullptr);
   EXPECT_NE(EEVEE_shaders_volumes_accum_sh_get(), nullptr);
   EXPECT_NE(EEVEE_shaders_studiolight_probe_sh_get(), nullptr);
   EXPECT_NE(EEVEE_shaders_studiolight_background_sh_get(), nullptr);