Workbench: Make object ID pass optionnal

We separate the background and foreground shading passes to be able to make
the object id pass optionnal if we don't need it.

This saves a bit more memory. Also not clearing all rendertargets saves
some GPU time too.

5 files changed, 117 insertions, 40 deletions

diff --git a/source/blender/draw/CMakeLists.txt b/source/blender/draw/CMakeLists.txt
index 70dfa589cdc..c3afb6b307e 100644
--- a/source/blender/draw/CMakeLists.txt
+++ b/source/blender/draw/CMakeLists.txt
@@ -224,6 +224,7 @@ data_to_c_simple(engines/workbench/shaders/workbench_checkerboard_depth_frag.gls
 data_to_c_simple(engines/workbench/shaders/workbench_common_lib.glsl SRC)
 data_to_c_simple(engines/workbench/shaders/workbench_data_lib.glsl SRC)
 data_to_c_simple(engines/workbench/shaders/workbench_deferred_composite_frag.glsl SRC)
+data_to_c_simple(engines/workbench/shaders/workbench_deferred_background_frag.glsl SRC)
 data_to_c_simple(engines/workbench/shaders/workbench_effect_fxaa_frag.glsl SRC)
 data_to_c_simple(engines/workbench/shaders/workbench_effect_taa_frag.glsl SRC)
 data_to_c_simple(engines/workbench/shaders/workbench_forward_composite_frag.glsl SRC)
diff --git a/source/blender/draw/engines/workbench/shaders/workbench_deferred_background_frag.glsl b/source/blender/draw/engines/workbench/shaders/workbench_deferred_background_frag.glsl
new file mode 100644
index 00000000000..9e4394238ff
--- /dev/null
+++ b/source/blender/draw/engines/workbench/shaders/workbench_deferred_background_frag.glsl
@@ -0,0 +1,39 @@
+
+uniform usampler2D objectId;
+
+uniform vec2 invertedViewportSize;
+
+out vec4 fragColor;
+
+layout(std140) uniform world_block {
+	WorldData world_data;
+};
+
+void main()
+{
+	vec2 uv_viewport = gl_FragCoord.xy * invertedViewportSize;
+	vec3 background = background_color(world_data, uv_viewport.y);
+
+#ifndef V3D_SHADING_OBJECT_OUTLINE
+
+	fragColor = vec4(background, world_data.background_alpha);
+
+#else /* !V3D_SHADING_OBJECT_OUTLINE */
+
+	ivec2 texel = ivec2(gl_FragCoord.xy);
+	uint object_id = texelFetch(objectId, texel, 0).r;
+	float object_outline = calculate_object_outline(objectId, texel, object_id);
+
+	if (object_outline == 0.0) {
+		fragColor = vec4(background, world_data.background_alpha);
+	}
+	else {
+		/* Do correct alpha blending. */
+		vec4 background_color = vec4(background, 1.0) * world_data.background_alpha;
+		vec4 outline_color = vec4(world_data.object_outline_color.rgb, 1.0);
+		fragColor = mix(outline_color, background_color, object_outline);
+		fragColor = vec4(fragColor.rgb / max(1e-8, fragColor.a), fragColor.a);
+	}
+
+#endif /* !V3D_SHADING_OBJECT_OUTLINE */
+}
diff --git a/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl b/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl
index 96537c47f11..6d2af8557d0 100644
--- a/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl
+++ b/source/blender/draw/engines/workbench/shaders/workbench_deferred_composite_frag.glsl
@@ -26,32 +26,6 @@ void main()
 {
 	ivec2 texel = ivec2(gl_FragCoord.xy);
 	vec2 uv_viewport = gl_FragCoord.xy * invertedViewportSize;
-	uint object_id = texelFetch(objectId, texel, 0).r;
-
-	/* TODO separate this into its own shader. */
-#ifndef V3D_SHADING_OBJECT_OUTLINE
-	if (object_id == NO_OBJECT_ID) {
-		fragColor = vec4(background_color(world_data, uv_viewport.y), world_data.background_alpha);
-		return;
-	}
-#else /* !V3D_SHADING_OBJECT_OUTLINE */
-	float object_outline = calculate_object_outline(objectId, texel, object_id);
-
-	if (object_id == NO_OBJECT_ID) {
-		vec3 background = background_color(world_data, uv_viewport.y);
-		if (object_outline == 0.0) {
-			fragColor = vec4(background, world_data.background_alpha);
-		}
-		else {
-			/* Do correct alpha blending. */
-			vec4 background_color = vec4(background, 1.0) * world_data.background_alpha;
-			vec4 outline_color = vec4(world_data.object_outline_color.rgb, 1.0);
-			fragColor = mix(outline_color, background_color, object_outline);
-			fragColor = vec4(fragColor.rgb / max(1e-8, fragColor.a), fragColor.a);
-		}
-		return;
-	}
-#endif /* !V3D_SHADING_OBJECT_OUTLINE */
 
 	vec4 base_color = texelFetch(colorBuffer, texel, 0);
 
@@ -105,6 +79,8 @@ void main()
 #endif
 
 #ifdef V3D_SHADING_OBJECT_OUTLINE
+	uint object_id = texelFetch(objectId, texel, 0).r;
+	float object_outline = calculate_object_outline(objectId, texel, object_id);
 	shaded_color = mix(world_data.object_outline_color.rgb, shaded_color, object_outline);
 #endif
 
diff --git a/source/blender/draw/engines/workbench/workbench_deferred.c b/source/blender/draw/engines/workbench/workbench_deferred.c
index 957f5b99614..c3eb3d82810 100644
--- a/source/blender/draw/engines/workbench/workbench_deferred.c
+++ b/source/blender/draw/engines/workbench/workbench_deferred.c
@@ -31,6 +31,7 @@
 #include "BLI_dynstr.h"
 #include "BLI_utildefines.h"
 #include "BLI_rand.h"
+#include "BLI_string_utils.h"
 
 #include "BKE_node.h"
 #include "BKE_modifier.h"
@@ -60,6 +61,7 @@ static struct {
 	struct GPUShader *prepass_sh_cache[MAX_SHADERS];
 	struct GPUShader *composite_sh_cache[MAX_SHADERS];
 	struct GPUShader *cavity_sh[MAX_CAVITY_SHADERS];
+	struct GPUShader *background_sh[2];
 	struct GPUShader *ghost_resolve_sh;
 	struct GPUShader *shadow_fail_sh;
 	struct GPUShader *shadow_fail_manifold_sh;
@@ -91,6 +93,7 @@ extern char datatoc_workbench_prepass_vert_glsl[];
 extern char datatoc_workbench_prepass_frag_glsl[];
 extern char datatoc_workbench_cavity_frag_glsl[];
 extern char datatoc_workbench_deferred_composite_frag_glsl[];
+extern char datatoc_workbench_deferred_background_frag_glsl[];
 extern char datatoc_workbench_ghost_resolve_frag_glsl[];
 
 extern char datatoc_workbench_shadow_vert_glsl[];
@@ -118,10 +121,10 @@ static char *workbench_build_composite_frag(WORKBENCH_PrivateData *wpd)
 	BLI_dynstr_append(ds, datatoc_workbench_common_lib_glsl);
 	BLI_dynstr_append(ds, datatoc_workbench_background_lib_glsl);
 
-	if ((wpd->shading.light & V3D_LIGHTING_MATCAP) || (wpd->shading.light & V3D_LIGHTING_STUDIO) || (wpd->shading.flag & V3D_SHADING_SPECULAR_HIGHLIGHT)) {
+	if (!FLAT_ENABLED(wpd)) {
 		BLI_dynstr_append(ds, datatoc_workbench_world_light_lib_glsl);
 	}
-	if (wpd->shading.flag & V3D_SHADING_OBJECT_OUTLINE) {
+	if (OBJECT_OUTLINE_ENABLED(wpd)) {
 		BLI_dynstr_append(ds, datatoc_workbench_object_outline_lib_glsl);
 	}
 	if (CURVATURE_ENABLED(wpd)) {
@@ -182,6 +185,9 @@ static char *workbench_build_cavity_frag(bool cavity, bool curvature, bool high_
 	if (high_dpi) {
 		BLI_dynstr_append(ds, "#define CURVATURE_OFFSET 2\n");
 	}
+	if (NORMAL_ENCODING_ENABLED()) {
+		BLI_dynstr_append(ds, "#define WORKBENCH_ENCODE_NORMALS\n");
+	}
 	BLI_dynstr_append(ds, datatoc_workbench_common_lib_glsl);
 	BLI_dynstr_append(ds, datatoc_workbench_curvature_lib_glsl);
 	BLI_dynstr_append(ds, datatoc_workbench_cavity_frag_glsl);
@@ -229,8 +235,24 @@ static void ensure_deferred_shaders(WORKBENCH_PrivateData *wpd, int index, bool
 	}
 }
 
+static void ensure_background_shaders(const bool use_outline)
+{
+	if (e_data.background_sh[use_outline] == NULL) {
+		const char *defines = (use_outline) ? "#define V3D_SHADING_OBJECT_OUTLINE\n" : NULL;
+		char *frag = BLI_string_joinN(
+		        datatoc_workbench_data_lib_glsl,
+		        datatoc_workbench_common_lib_glsl,
+		        datatoc_workbench_background_lib_glsl,
+		        datatoc_workbench_object_outline_lib_glsl,
+		        datatoc_workbench_deferred_background_frag_glsl);
+		e_data.background_sh[use_outline] = DRW_shader_create_fullscreen(frag, defines);
+		MEM_freeN(frag);
+	}
+}
+
 static void select_deferred_shaders(WORKBENCH_PrivateData *wpd)
 {
+	const bool use_outline = OBJECT_OUTLINE_ENABLED(wpd);
 	int index_solid = workbench_material_get_shader_index(wpd, false, false);
 	int index_solid_hair = workbench_material_get_shader_index(wpd, false, true);
 	int index_texture = workbench_material_get_shader_index(wpd, true, false);
@@ -240,12 +262,14 @@ static void select_deferred_shaders(WORKBENCH_PrivateData *wpd)
 	ensure_deferred_shaders(wpd, index_solid_hair, false, true);
 	ensure_deferred_shaders(wpd, index_texture, true, false);
 	ensure_deferred_shaders(wpd, index_texture_hair, true, true);
+	ensure_background_shaders(use_outline);
 
 	wpd->prepass_solid_sh = e_data.prepass_sh_cache[index_solid];
 	wpd->prepass_solid_hair_sh = e_data.prepass_sh_cache[index_solid_hair];
 	wpd->prepass_texture_sh = e_data.prepass_sh_cache[index_texture];
 	wpd->prepass_texture_hair_sh = e_data.prepass_sh_cache[index_texture_hair];
 	wpd->composite_sh = e_data.composite_sh_cache[index_solid];
+	wpd->background_sh = e_data.background_sh[use_outline];
 }
 
 
@@ -377,7 +401,6 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
 	{
 		const float *viewport_size = DRW_viewport_size_get();
 		const int size[2] = {(int)viewport_size[0], (int)viewport_size[1]};
-		const GPUTextureFormat id_tex_format = OBJECT_ID_PASS_ENABLED(wpd) ? GPU_R32UI : GPU_R8UI;
 		const GPUTextureFormat nor_tex_format = NORMAL_ENCODING_ENABLED() ? GPU_RG16 : GPU_RGBA32F;
 		const GPUTextureFormat comp_tex_format = DRW_state_is_image_render() ? GPU_RGBA16F : GPU_R11F_G11F_B10F;
 
@@ -388,9 +411,11 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
 		e_data.cavity_buffer_tx = NULL;
 		e_data.metallic_buffer_tx = NULL;
 
-		e_data.object_id_tx = DRW_texture_pool_query_2D(size[0], size[1], id_tex_format, &draw_engine_workbench_solid);
 		e_data.color_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_RGBA8, &draw_engine_workbench_solid);
 		e_data.composite_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], comp_tex_format, &draw_engine_workbench_solid);
+		if (OBJECT_ID_PASS_ENABLED(wpd)) {
+			e_data.object_id_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_R32UI, &draw_engine_workbench_solid);
+		}
 		if (NORMAL_VIEWPORT_PASS_ENABLED(wpd)) {
 			e_data.normal_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], nor_tex_format, &draw_engine_workbench_solid);
 		}
@@ -424,6 +449,13 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
 			GPU_ATTACHMENT_NONE,
 			GPU_ATTACHMENT_TEXTURE(e_data.color_buffer_tx),
 		});
+
+		if (OBJECT_ID_PASS_ENABLED(wpd)) {
+			GPU_framebuffer_ensure_config(&fbl->id_clear_fb, {
+				GPU_ATTACHMENT_NONE,
+				GPU_ATTACHMENT_TEXTURE(e_data.object_id_tx),
+			});
+		}
 	}
 
 	{
@@ -480,7 +512,6 @@ void workbench_deferred_engine_init(WORKBENCH_Data *vedata)
 
 		if (SSAO_ENABLED(wpd)) {
 			DRW_shgroup_uniform_texture_ref(grp, "depthBuffer", &dtxl->depth);
-			DRW_shgroup_uniform_texture_ref(grp, "colorBuffer", &e_data.color_buffer_tx);
 			DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
 			DRW_shgroup_uniform_vec4(grp, "viewvecs[0]", (float *)wpd->viewvecs, 3);
 			DRW_shgroup_uniform_vec4(grp, "ssao_params", wpd->ssao_params, 1);
@@ -525,6 +556,8 @@ void workbench_deferred_engine_free(void)
 	DRW_SHADER_FREE_SAFE(e_data.ghost_resolve_sh);
 	DRW_UBO_FREE_SAFE(e_data.sampling_ubo);
 	DRW_TEXTURE_FREE_SAFE(e_data.jitter_tx);
+	DRW_SHADER_FREE_SAFE(e_data.background_sh[0]);
+	DRW_SHADER_FREE_SAFE(e_data.background_sh[1]);
 
 	DRW_SHADER_FREE_SAFE(e_data.shadow_pass_sh);
 	DRW_SHADER_FREE_SAFE(e_data.shadow_pass_manifold_sh);
@@ -540,8 +573,11 @@ void workbench_deferred_engine_free(void)
 
 static void workbench_composite_uniforms(WORKBENCH_PrivateData *wpd, DRWShadingGroup *grp)
 {
+	DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
 	DRW_shgroup_uniform_texture_ref(grp, "colorBuffer", &e_data.color_buffer_tx);
-	DRW_shgroup_uniform_texture_ref(grp, "objectId", &e_data.object_id_tx);
+	if (OBJECT_OUTLINE_ENABLED(wpd)) {
+		DRW_shgroup_uniform_texture_ref(grp, "objectId", &e_data.object_id_tx);
+	}
 	if (NORMAL_VIEWPORT_COMP_PASS_ENABLED(wpd)) {
 		DRW_shgroup_uniform_texture_ref(grp, "normalBuffer", &e_data.normal_buffer_tx);
 	}
@@ -554,9 +590,9 @@ static void workbench_composite_uniforms(WORKBENCH_PrivateData *wpd, DRWShadingG
 	if (SPECULAR_HIGHLIGHT_ENABLED(wpd) || STUDIOLIGHT_TYPE_MATCAP_ENABLED(wpd)) {
 		DRW_shgroup_uniform_vec4(grp, "viewvecs[0]", (float *)wpd->viewvecs, 3);
 	}
-	DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
-	DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
-
+	if (SPECULAR_HIGHLIGHT_ENABLED(wpd) || STUDIOLIGHT_TYPE_MATCAP_ENABLED(wpd)) {
+		DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
+	}
 	if (STUDIOLIGHT_TYPE_MATCAP_ENABLED(wpd)) {
 		BKE_studiolight_ensure_flag(wpd->studio_light, STUDIOLIGHT_EQUIRECT_RADIANCE_GPUTEXTURE);
 		DRW_shgroup_uniform_texture(grp, "matcapImage", wpd->studio_light->equirect_radiance_gputexture);
@@ -577,6 +613,19 @@ void workbench_deferred_cache_init(WORKBENCH_Data *vedata)
 
 	select_deferred_shaders(wpd);
 
+	/* Background Pass */
+	{
+		psl->background_pass = DRW_pass_create(
+		        "Background", DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_EQUAL);
+		grp = DRW_shgroup_create(wpd->background_sh, psl->background_pass);
+		DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
+		DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
+		if (OBJECT_OUTLINE_ENABLED(wpd)) {
+			DRW_shgroup_uniform_texture_ref(grp, "objectId", &e_data.object_id_tx);
+		}
+		DRW_shgroup_call_add(grp, DRW_cache_fullscreen_quad_get(), NULL);
+	}
+
 	/* Deferred Mix Pass */
 	{
 		workbench_private_data_get_light_direction(wpd, e_data.display.light_direction);
@@ -589,7 +638,7 @@ void workbench_deferred_cache_init(WORKBENCH_Data *vedata)
 
 		if (SHADOW_ENABLED(wpd)) {
 			psl->composite_pass = DRW_pass_create(
-			        "Composite", DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL);
+			        "Composite", DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_EQUAL | DRW_STATE_DEPTH_GREATER);
 			grp = DRW_shgroup_create(wpd->composite_sh, psl->composite_pass);
 			workbench_composite_uniforms(wpd, grp);
 			DRW_shgroup_stencil_mask(grp, 0x00);
@@ -628,7 +677,8 @@ void workbench_deferred_cache_init(WORKBENCH_Data *vedata)
 			grp = DRW_shgroup_create(e_data.shadow_caps_manifold_sh, psl->shadow_depth_fail_caps_mani_pass);
 			DRW_shgroup_stencil_mask(grp, 0xFF);
 
-			psl->composite_shadow_pass = DRW_pass_create("Composite Shadow", DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_NEQUAL);
+			psl->composite_shadow_pass = DRW_pass_create(
+			        "Composite Shadow", DRW_STATE_WRITE_COLOR | DRW_STATE_STENCIL_NEQUAL | DRW_STATE_DEPTH_GREATER);
 			grp = DRW_shgroup_create(wpd->composite_sh, psl->composite_shadow_pass);
 			DRW_shgroup_stencil_mask(grp, 0x00);
 			workbench_composite_uniforms(wpd, grp);
@@ -638,11 +688,10 @@ void workbench_deferred_cache_init(WORKBENCH_Data *vedata)
 			DRW_shgroup_uniform_float_copy(grp, "shadowFocus", shadow_focus);
 			DRW_shgroup_call_add(grp, DRW_cache_fullscreen_quad_get(), NULL);
 #endif
-
 		}
 		else {
 			psl->composite_pass = DRW_pass_create(
-			        "Composite", DRW_STATE_WRITE_COLOR);
+			        "Composite", DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_GREATER);
 			grp = DRW_shgroup_create(wpd->composite_sh, psl->composite_pass);
 			workbench_composite_uniforms(wpd, grp);
 			DRW_shgroup_call_add(grp, DRW_cache_fullscreen_quad_get(), NULL);
@@ -915,8 +964,15 @@ void workbench_deferred_draw_background(WORKBENCH_Data *vedata)
 	uint clear_stencil = 0x00;
 
 	DRW_stats_group_start("Clear Background");
+
+	if (OBJECT_ID_PASS_ENABLED(wpd)) {
+		/* From all the color buffers, only object id needs to be cleared. */
+		GPU_framebuffer_bind(fbl->id_clear_fb);
+		GPU_framebuffer_clear_color(fbl->id_clear_fb, clear_color);
+	}
+
 	GPU_framebuffer_bind(fbl->prepass_fb);
-	int clear_bits = GPU_DEPTH_BIT | GPU_COLOR_BIT;
+	int clear_bits = GPU_DEPTH_BIT;
 	SET_FLAG_FROM_TEST(clear_bits, SHADOW_ENABLED(wpd), GPU_STENCIL_BIT);
 	GPU_framebuffer_clear(fbl->prepass_fb, clear_bits, clear_color, clear_depth, clear_stencil);
 	DRW_stats_group_end();
@@ -1006,6 +1062,8 @@ void workbench_deferred_draw_scene(WORKBENCH_Data *vedata)
 		DRW_draw_pass(psl->ghost_prepass_hair_pass);
 	}
 
+	DRW_draw_pass(psl->background_pass);
+
 	if (wpd->volumes_do) {
 		GPU_framebuffer_bind(fbl->volume_fb);
 		DRW_draw_pass(psl->volume_pass);
diff --git a/source/blender/draw/engines/workbench/workbench_private.h b/source/blender/draw/engines/workbench/workbench_private.h
index e2b1c631391..9fa7304e1ef 100644
--- a/source/blender/draw/engines/workbench/workbench_private.h
+++ b/source/blender/draw/engines/workbench/workbench_private.h
@@ -81,6 +81,7 @@ typedef struct WORKBENCH_FramebufferList {
 	struct GPUFrameBuffer *ghost_prepass_fb;
 	struct GPUFrameBuffer *cavity_fb;
 	struct GPUFrameBuffer *composite_fb;
+	struct GPUFrameBuffer *id_clear_fb;
 
 	struct GPUFrameBuffer *effect_fb;
 	struct GPUFrameBuffer *effect_taa_fb;
@@ -118,6 +119,7 @@ typedef struct WORKBENCH_PassList {
 	struct DRWPass *shadow_depth_fail_caps_mani_pass;
 	struct DRWPass *composite_pass;
 	struct DRWPass *composite_shadow_pass;
+	struct DRWPass *background_pass;
 	struct DRWPass *ghost_resolve_pass;
 	struct DRWPass *effect_aa_pass;
 	struct DRWPass *volume_pass;
@@ -167,6 +169,7 @@ typedef struct WORKBENCH_PrivateData {
 	struct GPUShader *prepass_texture_sh;
 	struct GPUShader *prepass_texture_hair_sh;
 	struct GPUShader *composite_sh;
+	struct GPUShader *background_sh;
 	struct GPUShader *transparent_accum_sh;
 	struct GPUShader *transparent_accum_hair_sh;
 	struct GPUShader *transparent_accum_texture_sh;