Use prefiltered radiance

6 files changed, 90 insertions, 33 deletions

diff --git a/servers/rendering/renderer_rd/effects_rd.cpp b/servers/rendering/renderer_rd/effects_rd.cpp
index 02a0b6f184..6c28cfd134 100644
--- a/servers/rendering/renderer_rd/effects_rd.cpp
+++ b/servers/rendering/renderer_rd/effects_rd.cpp
@@ -2040,7 +2040,7 @@ void EffectsRD::cubemap_roughness(RID p_source_rd_texture, RID p_dest_texture, u
 	RD::ComputeListID compute_list = RD::get_singleton()->compute_list_begin();
 	RD::get_singleton()->compute_list_bind_compute_pipeline(compute_list, roughness.compute_pipeline);
 
-	RD::get_singleton()->compute_list_bind_uniform_set(compute_list, _get_compute_uniform_set_from_texture(p_source_rd_texture), 0);
+	RD::get_singleton()->compute_list_bind_uniform_set(compute_list, _get_compute_uniform_set_from_texture(p_source_rd_texture, true), 0);
 	RD::get_singleton()->compute_list_bind_uniform_set(compute_list, _get_uniform_set_from_image(p_dest_texture), 1);
 
 	RD::get_singleton()->compute_list_set_push_constant(compute_list, &roughness.push_constant, sizeof(CubemapRoughnessPushConstant));
diff --git a/servers/rendering/renderer_rd/renderer_scene_sky_rd.cpp b/servers/rendering/renderer_rd/renderer_scene_sky_rd.cpp
index 354516ae87..b44ae6cf8d 100644
--- a/servers/rendering/renderer_rd/renderer_scene_sky_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_scene_sky_rd.cpp
@@ -473,12 +473,13 @@ void RendererSceneSkyRD::ReflectionData::create_reflection_fast_filter(RendererS
 		}
 		RD::get_singleton()->draw_command_end_label(); // Filter radiance
 	} else {
+		RD::get_singleton()->draw_command_begin_label("Downsample radiance map");
 		effects->cubemap_downsample(radiance_base_cubemap, downsampled_layer.mipmaps[0].view, downsampled_layer.mipmaps[0].size);
 
 		for (int i = 1; i < downsampled_layer.mipmaps.size(); i++) {
 			effects->cubemap_downsample(downsampled_layer.mipmaps[i - 1].view, downsampled_layer.mipmaps[i].view, downsampled_layer.mipmaps[i].size);
 		}
-
+		RD::get_singleton()->draw_command_end_label(); // Downsample Radiance
 		Vector<RID> views;
 		if (p_use_arrays) {
 			for (int i = 1; i < layers.size(); i++) {
@@ -489,8 +490,9 @@ void RendererSceneSkyRD::ReflectionData::create_reflection_fast_filter(RendererS
 				views.push_back(layers[0].views[i]);
 			}
 		}
-
+		RD::get_singleton()->draw_command_begin_label("Fast filter radiance");
 		effects->cubemap_filter(downsampled_radiance_cubemap, views, p_use_arrays);
+		RD::get_singleton()->draw_command_end_label(); // Filter radiance
 	}
 }
 
@@ -500,12 +502,25 @@ void RendererSceneSkyRD::ReflectionData::create_reflection_importance_sample(Ren
 	bool prefer_raster_effects = effects->get_prefer_raster_effects();
 
 	if (prefer_raster_effects) {
-		// Need to ask clayjohn but p_cube_side is set to 10, looks like in the compute shader we're doing all 6 sides in one call
-		// here we need to do them one by one so ignoring p_cube_side
+		if (p_base_layer == 1) {
+			RD::get_singleton()->draw_command_begin_label("Downsample radiance map");
+			for (int k = 0; k < 6; k++) {
+				effects->cubemap_downsample_raster(radiance_base_cubemap, downsampled_layer.mipmaps[0].framebuffers[k], k, downsampled_layer.mipmaps[0].size);
+			}
+
+			for (int i = 1; i < downsampled_layer.mipmaps.size(); i++) {
+				for (int k = 0; k < 6; k++) {
+					effects->cubemap_downsample_raster(downsampled_layer.mipmaps[i - 1].view, downsampled_layer.mipmaps[i].framebuffers[k], k, downsampled_layer.mipmaps[i].size);
+				}
+			}
+			RD::get_singleton()->draw_command_end_label(); // Downsample Radiance
+		}
+
+		RD::get_singleton()->draw_command_begin_label("High Quality filter radiance");
 		if (p_use_arrays) {
 			for (int k = 0; k < 6; k++) {
 				effects->cubemap_roughness_raster(
-						radiance_base_cubemap,
+						downsampled_radiance_cubemap,
 						layers[p_base_layer].mipmaps[0].framebuffers[k],
 						k,
 						p_sky_ggx_samples_quality,
@@ -515,7 +530,7 @@ void RendererSceneSkyRD::ReflectionData::create_reflection_importance_sample(Ren
 		} else {
 			for (int k = 0; k < 6; k++) {
 				effects->cubemap_roughness_raster(
-						layers[0].views[p_base_layer - 1],
+						downsampled_radiance_cubemap,
 						layers[0].mipmaps[p_base_layer].framebuffers[k],
 						k,
 						p_sky_ggx_samples_quality,
@@ -524,12 +539,22 @@ void RendererSceneSkyRD::ReflectionData::create_reflection_importance_sample(Ren
 			}
 		}
 	} else {
+		if (p_base_layer == 1) {
+			RD::get_singleton()->draw_command_begin_label("Downsample radiance map");
+			effects->cubemap_downsample(radiance_base_cubemap, downsampled_layer.mipmaps[0].view, downsampled_layer.mipmaps[0].size);
+
+			for (int i = 1; i < downsampled_layer.mipmaps.size(); i++) {
+				effects->cubemap_downsample(downsampled_layer.mipmaps[i - 1].view, downsampled_layer.mipmaps[i].view, downsampled_layer.mipmaps[i].size);
+			}
+			RD::get_singleton()->draw_command_end_label(); // Downsample Radiance
+		}
+
+		RD::get_singleton()->draw_command_begin_label("High Quality filter radiance");
 		if (p_use_arrays) {
-			//render directly to the layers
-			effects->cubemap_roughness(radiance_base_cubemap, layers[p_base_layer].views[0], p_cube_side, p_sky_ggx_samples_quality, float(p_base_layer) / (layers.size() - 1.0), layers[p_base_layer].mipmaps[0].size.x);
+			effects->cubemap_roughness(downsampled_radiance_cubemap, layers[p_base_layer].views[0], p_cube_side, p_sky_ggx_samples_quality, float(p_base_layer) / (layers.size() - 1.0), layers[p_base_layer].mipmaps[0].size.x);
 		} else {
 			effects->cubemap_roughness(
-					layers[0].views[p_base_layer - 1],
+					downsampled_radiance_cubemap,
 					layers[0].views[p_base_layer],
 					p_cube_side,
 					p_sky_ggx_samples_quality,
@@ -537,6 +562,7 @@ void RendererSceneSkyRD::ReflectionData::create_reflection_importance_sample(Ren
 					layers[0].mipmaps[p_base_layer].size.x);
 		}
 	}
+	RD::get_singleton()->draw_command_end_label(); // Filter radiance
 }
 
 void RendererSceneSkyRD::ReflectionData::update_reflection_mipmaps(RendererStorageRD *p_storage, int p_start, int p_end) {
diff --git a/servers/rendering/renderer_rd/shaders/cubemap_roughness.glsl b/servers/rendering/renderer_rd/shaders/cubemap_roughness.glsl
index 28f4dc59ec..1d46f59408 100644
--- a/servers/rendering/renderer_rd/shaders/cubemap_roughness.glsl
+++ b/servers/rendering/renderer_rd/shaders/cubemap_roughness.glsl
@@ -21,24 +21,38 @@ void main() {
 	vec2 uv = ((vec2(id.xy) * 2.0 + 1.0) / (params.face_size) - 1.0);
 	vec3 N = texelCoordToVec(uv, id.z);
 
-	//vec4 color = color_interp;
-
 	if (params.use_direct_write) {
 		imageStore(dest_cubemap, ivec3(id), vec4(texture(source_cube, N).rgb, 1.0));
 	} else {
 		vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);
 
+		float solid_angle_texel = 4.0 * M_PI / (6.0 * params.face_size * params.face_size);
+		float roughness2 = params.roughness * params.roughness;
+		float roughness4 = roughness2 * roughness2;
+		vec3 UpVector = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
+		mat3 T;
+		T[0] = normalize(cross(UpVector, N));
+		T[1] = cross(N, T[0]);
+		T[2] = N;
+
 		for (uint sampleNum = 0u; sampleNum < params.sample_count; sampleNum++) {
 			vec2 xi = Hammersley(sampleNum, params.sample_count);
 
-			vec3 H = ImportanceSampleGGX(xi, params.roughness, N);
-			vec3 V = N;
-			vec3 L = (2.0 * dot(V, H) * H - V);
+			vec3 H = T * ImportanceSampleGGX(xi, roughness4);
+			float NdotH = dot(N, H);
+			vec3 L = (2.0 * NdotH * H - N);
 
 			float ndotl = clamp(dot(N, L), 0.0, 1.0);
 
 			if (ndotl > 0.0) {
-				sum.rgb += textureLod(source_cube, L, 0.0).rgb * ndotl;
+				float D = DistributionGGX(NdotH, roughness4);
+				float pdf = D * NdotH / (4.0 * NdotH) + 0.0001;
+
+				float solid_angle_sample = 1.0 / (float(params.sample_count) * pdf + 0.0001);
+
+				float mipLevel = params.roughness == 0.0 ? 0.0 : 0.5 * log2(solid_angle_sample / solid_angle_texel);
+
+				sum.rgb += textureLod(source_cube, L, mipLevel).rgb * ndotl;
 				sum.a += ndotl;
 			}
 		}
diff --git a/servers/rendering/renderer_rd/shaders/cubemap_roughness_inc.glsl b/servers/rendering/renderer_rd/shaders/cubemap_roughness_inc.glsl
index ce0a25e12f..1bee428a6f 100644
--- a/servers/rendering/renderer_rd/shaders/cubemap_roughness_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/cubemap_roughness_inc.glsl
@@ -47,12 +47,10 @@ vec3 texelCoordToVec(vec2 uv, uint faceID) {
 	return normalize(result);
 }
 
-vec3 ImportanceSampleGGX(vec2 Xi, float Roughness, vec3 N) {
-	float a = Roughness * Roughness; // DISNEY'S ROUGHNESS [see Burley'12 siggraph]
-
+vec3 ImportanceSampleGGX(vec2 xi, float roughness4) {
 	// Compute distribution direction
-	float Phi = 2.0 * M_PI * Xi.x;
-	float CosTheta = sqrt((1.0 - Xi.y) / (1.0 + (a * a - 1.0) * Xi.y));
+	float Phi = 2.0 * M_PI * xi.x;
+	float CosTheta = sqrt((1.0 - xi.y) / (1.0 + (roughness4 - 1.0) * xi.y));
 	float SinTheta = sqrt(1.0 - CosTheta * CosTheta);
 
 	// Convert to spherical direction
@@ -61,12 +59,15 @@ vec3 ImportanceSampleGGX(vec2 Xi, float Roughness, vec3 N) {
 	H.y = SinTheta * sin(Phi);
 	H.z = CosTheta;
 
-	vec3 UpVector = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
-	vec3 TangentX = normalize(cross(UpVector, N));
-	vec3 TangentY = cross(N, TangentX);
+	return H;
+}
+
+float DistributionGGX(float NdotH, float roughness4) {
+	float NdotH2 = NdotH * NdotH;
+	float denom = (NdotH2 * (roughness4 - 1.0) + 1.0);
+	denom = M_PI * denom * denom;
 
-	// Tangent to world space
-	return TangentX * H.x + TangentY * H.y + N * H.z;
+	return roughness4 / denom;
 }
 
 // https://graphicrants.blogspot.com.au/2013/08/specular-brdf-reference.html
diff --git a/servers/rendering/renderer_rd/shaders/cubemap_roughness_raster.glsl b/servers/rendering/renderer_rd/shaders/cubemap_roughness_raster.glsl
index 2570308816..c29accd8a7 100644
--- a/servers/rendering/renderer_rd/shaders/cubemap_roughness_raster.glsl
+++ b/servers/rendering/renderer_rd/shaders/cubemap_roughness_raster.glsl
@@ -42,17 +42,33 @@ void main() {
 	} else {
 		vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);
 
+		float solid_angle_texel = 4.0 * M_PI / (6.0 * params.face_size * params.face_size);
+		float roughness2 = params.roughness * params.roughness;
+		float roughness4 = roughness2 * roughness2;
+		vec3 UpVector = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
+		mat3 T;
+		T[0] = normalize(cross(UpVector, N));
+		T[1] = cross(N, T[0]);
+		T[2] = N;
+
 		for (uint sampleNum = 0u; sampleNum < params.sample_count; sampleNum++) {
 			vec2 xi = Hammersley(sampleNum, params.sample_count);
 
-			vec3 H = ImportanceSampleGGX(xi, params.roughness, N);
-			vec3 V = N;
-			vec3 L = (2.0 * dot(V, H) * H - V);
+			vec3 H = T * ImportanceSampleGGX(xi, roughness4);
+			float NdotH = dot(N, H);
+			vec3 L = (2.0 * NdotH * H - N);
 
 			float ndotl = clamp(dot(N, L), 0.0, 1.0);
 
 			if (ndotl > 0.0) {
-				sum.rgb += textureLod(source_cube, L, 0.0).rgb * ndotl;
+				float D = DistributionGGX(NdotH, roughness4);
+				float pdf = D * NdotH / (4.0 * NdotH) + 0.0001;
+
+				float solid_angle_sample = 1.0 / (float(params.sample_count) * pdf + 0.0001);
+
+				float mipLevel = params.roughness == 0.0 ? 0.0 : 0.5 * log2(solid_angle_sample / solid_angle_texel);
+
+				sum.rgb += textureLod(source_cube, L, mipLevel).rgb * ndotl;
 				sum.a += ndotl;
 			}
 		}
diff --git a/servers/rendering_server.cpp b/servers/rendering_server.cpp
index 2037268134..13521d3549 100644
--- a/servers/rendering_server.cpp
+++ b/servers/rendering_server.cpp
@@ -2860,11 +2860,11 @@ RenderingServer::RenderingServer() {
 	GLOBAL_DEF("rendering/shader_compiler/shader_cache/strip_debug", false);
 	GLOBAL_DEF("rendering/shader_compiler/shader_cache/strip_debug.release", true);
 
-	GLOBAL_DEF("rendering/reflections/sky_reflections/roughness_layers", 8);
+	GLOBAL_DEF_RST("rendering/reflections/sky_reflections/roughness_layers", 8); // Assumes a 256x256 cubemap
 	GLOBAL_DEF_RST("rendering/reflections/sky_reflections/texture_array_reflections", true);
 	GLOBAL_DEF("rendering/reflections/sky_reflections/texture_array_reflections.mobile", false);
-	GLOBAL_DEF("rendering/reflections/sky_reflections/ggx_samples", 1024);
-	GLOBAL_DEF("rendering/reflections/sky_reflections/ggx_samples.mobile", 128);
+	GLOBAL_DEF_RST("rendering/reflections/sky_reflections/ggx_samples", 32);
+	GLOBAL_DEF("rendering/reflections/sky_reflections/ggx_samples.mobile", 16);
 	GLOBAL_DEF("rendering/reflections/sky_reflections/fast_filter_high_quality", false);
 	GLOBAL_DEF("rendering/reflections/reflection_atlas/reflection_size", 256);
 	GLOBAL_DEF("rendering/reflections/reflection_atlas/reflection_size.mobile", 128);