Eevee: Fix Missing alpha when rendering with DOF

NOTE: There is a float imprecision near the focus plane
due to the current technique used for DOF. This makes the alpha channel
transparent on nearly in focus objects even when they should not.
This artifact should be fixed when the DOF will use scatter as gather for
low brightness areas.

Fix T57042 : Eevee does not render alpha when DOF is turned on

1 files changed, 46 insertions, 21 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_depth_of_field.c b/source/blender/draw/engines/eevee/eevee_depth_of_field.c
index e51fb2fd1d7..c36e8601d25 100644
--- a/source/blender/draw/engines/eevee/eevee_depth_of_field.c
+++ b/source/blender/draw/engines/eevee/eevee_depth_of_field.c
@@ -56,23 +56,32 @@
 
 static struct {
 	/* Depth Of Field */
-	struct GPUShader *dof_downsample_sh;
-	struct GPUShader *dof_scatter_sh;
-	struct GPUShader *dof_resolve_sh;
+	struct GPUShader *dof_downsample_sh[2];
+	struct GPUShader *dof_scatter_sh[2];
+	struct GPUShader *dof_resolve_sh[2];
 } e_data = {NULL}; /* Engine data */
 
 extern char datatoc_effect_dof_vert_glsl[];
 extern char datatoc_effect_dof_frag_glsl[];
 
-static void eevee_create_shader_depth_of_field(void)
+static void eevee_create_shader_depth_of_field(const bool use_alpha)
 {
-	e_data.dof_downsample_sh = DRW_shader_create_fullscreen(
-	        datatoc_effect_dof_frag_glsl, "#define STEP_DOWNSAMPLE\n");
-	e_data.dof_scatter_sh = DRW_shader_create(
+	e_data.dof_downsample_sh[use_alpha] = DRW_shader_create_fullscreen(
+	        datatoc_effect_dof_frag_glsl, use_alpha ?
+	                                      "#define USE_ALPHA_DOF\n"
+	                                      "#define STEP_DOWNSAMPLE\n" :
+	                                      "#define STEP_DOWNSAMPLE\n");
+	e_data.dof_scatter_sh[use_alpha] = DRW_shader_create(
 	        datatoc_effect_dof_vert_glsl, NULL,
-	        datatoc_effect_dof_frag_glsl, "#define STEP_SCATTER\n");
-	e_data.dof_resolve_sh = DRW_shader_create_fullscreen(
-	        datatoc_effect_dof_frag_glsl, "#define STEP_RESOLVE\n");
+	        datatoc_effect_dof_frag_glsl, use_alpha ?
+	                                      "#define USE_ALPHA_DOF\n"
+	                                      "#define STEP_SCATTER\n" :
+	                                      "#define STEP_SCATTER\n");
+	e_data.dof_resolve_sh[use_alpha] = DRW_shader_create_fullscreen(
+	        datatoc_effect_dof_frag_glsl, use_alpha ?
+	                                      "#define USE_ALPHA_DOF\n"
+	                                      "#define STEP_RESOLVE\n" :
+	                                      "#define STEP_RESOLVE\n");
 }
 
 int EEVEE_depth_of_field_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *vedata, Object *camera)
@@ -86,9 +95,10 @@ int EEVEE_depth_of_field_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *v
 
 	if (scene_eval->eevee.flag & SCE_EEVEE_DOF_ENABLED) {
 		RegionView3D *rv3d = draw_ctx->rv3d;
+		const bool use_alpha = !DRW_state_draw_background();
 
-		if (!e_data.dof_downsample_sh) {
-			eevee_create_shader_depth_of_field();
+		if (!e_data.dof_downsample_sh[use_alpha]) {
+			eevee_create_shader_depth_of_field(use_alpha);
 		}
 
 		if (camera) {
@@ -101,9 +111,11 @@ int EEVEE_depth_of_field_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *v
 
 			int buffer_size[2] = {(int)viewport_size[0] / 2, (int)viewport_size[1] / 2};
 
-			effects->dof_down_near = DRW_texture_pool_query_2D(buffer_size[0], buffer_size[1], GPU_R11F_G11F_B10F,
+			GPUTextureFormat down_format = DRW_state_draw_background() ? GPU_R11F_G11F_B10F : GPU_RGBA16F;
+
+			effects->dof_down_near = DRW_texture_pool_query_2D(buffer_size[0], buffer_size[1], down_format,
 			                                                   &draw_engine_eevee_type);
-			effects->dof_down_far =  DRW_texture_pool_query_2D(buffer_size[0], buffer_size[1], GPU_R11F_G11F_B10F,
+			effects->dof_down_far =  DRW_texture_pool_query_2D(buffer_size[0], buffer_size[1], down_format,
 			                                                   &draw_engine_eevee_type);
 			effects->dof_coc =       DRW_texture_pool_query_2D(buffer_size[0], buffer_size[1], GPU_RG16F,
 			                                                   &draw_engine_eevee_type);
@@ -120,11 +132,18 @@ int EEVEE_depth_of_field_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *v
 
 			effects->dof_blur = DRW_texture_pool_query_2D(buffer_size[0] * 2, buffer_size[1], fb_format,
 			                                              &draw_engine_eevee_type);
+
 			GPU_framebuffer_ensure_config(&fbl->dof_scatter_fb, {
 				GPU_ATTACHMENT_NONE,
 				GPU_ATTACHMENT_TEXTURE(effects->dof_blur),
 			});
 
+			if (!DRW_state_draw_background()) {
+				effects->dof_blur_alpha = DRW_texture_pool_query_2D(buffer_size[0] * 2, buffer_size[1], GPU_R32F,
+				                                                    &draw_engine_eevee_type);
+				GPU_framebuffer_texture_attach(fbl->dof_scatter_fb, effects->dof_blur_alpha, 1, 0);
+			}
+
 			/* Parameters */
 			/* TODO UI Options */
 			float fstop = cam->gpu_dof.fstop;
@@ -193,10 +212,11 @@ void EEVEE_depth_of_field_cache_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_
 		 **/
 		DRWShadingGroup *grp;
 		struct GPUBatch *quad = DRW_cache_fullscreen_quad_get();
+		const bool use_alpha = !DRW_state_draw_background();
 
 		psl->dof_down = DRW_pass_create("DoF Downsample", DRW_STATE_WRITE_COLOR);
 
-		grp = DRW_shgroup_create(e_data.dof_downsample_sh, psl->dof_down);
+		grp = DRW_shgroup_create(e_data.dof_downsample_sh[use_alpha], psl->dof_down);
 		DRW_shgroup_uniform_texture_ref(grp, "colorBuffer", &effects->source_buffer);
 		DRW_shgroup_uniform_texture_ref(grp, "depthBuffer", &dtxl->depth);
 		DRW_shgroup_uniform_vec2(grp, "nearFar", effects->dof_near_far, 1);
@@ -209,8 +229,7 @@ void EEVEE_depth_of_field_cache_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_
 		 * by the vertex shader 0.4ms against 6ms with instancing */
 		const float *viewport_size = DRW_viewport_size_get();
 		const int sprite_len = ((int)viewport_size[0] / 2) * ((int)viewport_size[1] / 2); /* brackets matters */
-		grp = DRW_shgroup_empty_tri_batch_create(e_data.dof_scatter_sh, psl->dof_scatter, sprite_len);
-
+		grp = DRW_shgroup_empty_tri_batch_create(e_data.dof_scatter_sh[use_alpha], psl->dof_scatter, sprite_len);
 		DRW_shgroup_uniform_texture_ref(grp, "nearBuffer", &effects->dof_down_near);
 		DRW_shgroup_uniform_texture_ref(grp, "farBuffer", &effects->dof_down_far);
 		DRW_shgroup_uniform_texture_ref(grp, "cocBuffer", &effects->dof_coc);
@@ -218,13 +237,17 @@ void EEVEE_depth_of_field_cache_init(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_
 
 		psl->dof_resolve = DRW_pass_create("DoF Resolve", DRW_STATE_WRITE_COLOR);
 
-		grp = DRW_shgroup_create(e_data.dof_resolve_sh, psl->dof_resolve);
+		grp = DRW_shgroup_create(e_data.dof_resolve_sh[use_alpha], psl->dof_resolve);
 		DRW_shgroup_uniform_texture_ref(grp, "scatterBuffer", &effects->dof_blur);
 		DRW_shgroup_uniform_texture_ref(grp, "colorBuffer", &effects->source_buffer);
 		DRW_shgroup_uniform_texture_ref(grp, "depthBuffer", &dtxl->depth);
 		DRW_shgroup_uniform_vec2(grp, "nearFar", effects->dof_near_far, 1);
 		DRW_shgroup_uniform_vec3(grp, "dofParams", effects->dof_params, 1);
 		DRW_shgroup_call_add(grp, quad, NULL);
+
+		if (use_alpha) {
+			DRW_shgroup_uniform_texture_ref(grp, "scatterAlphaBuffer", &effects->dof_blur_alpha);
+		}
 	}
 }
 
@@ -258,7 +281,9 @@ void EEVEE_depth_of_field_draw(EEVEE_Data *vedata)
 
 void EEVEE_depth_of_field_free(void)
 {
-	DRW_SHADER_FREE_SAFE(e_data.dof_downsample_sh);
-	DRW_SHADER_FREE_SAFE(e_data.dof_scatter_sh);
-	DRW_SHADER_FREE_SAFE(e_data.dof_resolve_sh);
+	for (int i = 0; i < 2; ++i) {
+		DRW_SHADER_FREE_SAFE(e_data.dof_downsample_sh[i]);
+		DRW_SHADER_FREE_SAFE(e_data.dof_scatter_sh[i]);
+		DRW_SHADER_FREE_SAFE(e_data.dof_resolve_sh[i]);
+	}
 }