Merge pull request #100544 from Namey5/sdfgi-sky-rotation

Support custom sky rotation in SDFGI

servers/rendering/renderer_rd/environment/gi.cpp

@@ -1307,24 +1307,24 @@ void GI::SDFGI::update_probes(RID p_env, SkyRD::Sky *p_sky) {
 	push_constant.store_ambient_texture = RendererSceneRenderRD::get_singleton()->environment_get_volumetric_fog_enabled(p_env);
 
 	RID sky_uniform_set = gi->sdfgi_shader.integrate_default_sky_uniform_set;
-	push_constant.sky_mode = SDFGIShader::IntegratePushConstant::SKY_MODE_DISABLED;
+	push_constant.sky_flags = 0;
 	push_constant.y_mult = y_mult;
 
 	if (reads_sky && p_env.is_valid()) {
 		push_constant.sky_energy = RendererSceneRenderRD::get_singleton()->environment_get_bg_energy_multiplier(p_env);
 
 		if (RendererSceneRenderRD::get_singleton()->environment_get_background(p_env) == RS::ENV_BG_CLEAR_COLOR) {
-			push_constant.sky_mode = SDFGIShader::IntegratePushConstant::SKY_MODE_COLOR;
+			push_constant.sky_flags |= SDFGIShader::IntegratePushConstant::SKY_FLAGS_MODE_COLOR;
 			Color c = RSG::texture_storage->get_default_clear_color().srgb_to_linear();
-			push_constant.sky_color[0] = c.r;
-			push_constant.sky_color[1] = c.g;
-			push_constant.sky_color[2] = c.b;
+			push_constant.sky_color_or_orientation[0] = c.r;
+			push_constant.sky_color_or_orientation[1] = c.g;
+			push_constant.sky_color_or_orientation[2] = c.b;
 		} else if (RendererSceneRenderRD::get_singleton()->environment_get_background(p_env) == RS::ENV_BG_COLOR) {
-			push_constant.sky_mode = SDFGIShader::IntegratePushConstant::SKY_MODE_COLOR;
+			push_constant.sky_flags |= SDFGIShader::IntegratePushConstant::SKY_FLAGS_MODE_COLOR;
 			Color c = RendererSceneRenderRD::get_singleton()->environment_get_bg_color(p_env);
-			push_constant.sky_color[0] = c.r;
-			push_constant.sky_color[1] = c.g;
-			push_constant.sky_color[2] = c.b;
+			push_constant.sky_color_or_orientation[0] = c.r;
+			push_constant.sky_color_or_orientation[1] = c.g;
+			push_constant.sky_color_or_orientation[2] = c.b;
 
 		} else if (RendererSceneRenderRD::get_singleton()->environment_get_background(p_env) == RS::ENV_BG_SKY) {
 			if (p_sky && p_sky->radiance.is_valid()) {
@@ -1350,7 +1350,16 @@ void GI::SDFGI::update_probes(RID p_env, SkyRD::Sky *p_sky) {
 					integrate_sky_uniform_set = RD::get_singleton()->uniform_set_create(uniforms, gi->sdfgi_shader.integrate.version_get_shader(gi->sdfgi_shader.integrate_shader, 0), 1);
 				}
 				sky_uniform_set = integrate_sky_uniform_set;
-				push_constant.sky_mode = SDFGIShader::IntegratePushConstant::SKY_MODE_SKY;
+				push_constant.sky_flags |= SDFGIShader::IntegratePushConstant::SKY_FLAGS_MODE_SKY;
+
+				// Encode sky orientation as quaternion in existing push constants.
+				const Basis sky_basis = RendererSceneRenderRD::get_singleton()->environment_get_sky_orientation(p_env);
+				const Quaternion sky_quaternion = sky_basis.get_quaternion().inverse();
+				push_constant.sky_color_or_orientation[0] = sky_quaternion.x;
+				push_constant.sky_color_or_orientation[1] = sky_quaternion.y;
+				push_constant.sky_color_or_orientation[2] = sky_quaternion.z;
+				// Ideally we would reconstruct the largest component for least error, but sky contribution to GI is low frequency so just needs to get the idea across.
+				push_constant.sky_flags |= SDFGIShader::IntegratePushConstant::SKY_FLAGS_ORIENTATION_SIGN * (sky_quaternion.w < 0.0 ? 0 : 1);
 			}
 		}
 	}
@@ -1396,7 +1405,7 @@ void GI::SDFGI::store_probes() {
 	push_constant.image_size[1] = probe_axis_count;
 	push_constant.store_ambient_texture = false;
 
-	push_constant.sky_mode = 0;
+	push_constant.sky_flags = 0;
 	push_constant.y_mult = y_mult;
 
 	// Then store values into the lightprobe texture. Separating these steps has a small performance hit, but it allows for multiple bounces
@@ -2092,11 +2101,11 @@ void GI::SDFGI::render_region(Ref<RenderSceneBuffersRD> p_render_buffers, int p_
 				ipush_constant.history_size = history_size;
 				ipush_constant.ray_count = 0;
 				ipush_constant.ray_bias = 0;
-				ipush_constant.sky_mode = 0;
+				ipush_constant.sky_flags = 0;
 				ipush_constant.sky_energy = 0;
-				ipush_constant.sky_color[0] = 0;
-				ipush_constant.sky_color[1] = 0;
-				ipush_constant.sky_color[2] = 0;
+				ipush_constant.sky_color_or_orientation[0] = 0;
+				ipush_constant.sky_color_or_orientation[1] = 0;
+				ipush_constant.sky_color_or_orientation[2] = 0;
 				ipush_constant.y_mult = y_mult;
 				ipush_constant.store_ambient_texture = false;
 

servers/rendering/renderer_rd/environment/gi.h

@@ -392,9 +392,9 @@ private:
 		};
 		struct IntegratePushConstant {
 			enum {
-				SKY_MODE_DISABLED,
-				SKY_MODE_COLOR,
-				SKY_MODE_SKY,
+				SKY_FLAGS_MODE_COLOR = 0x01,
+				SKY_FLAGS_MODE_SKY = 0x02,
+				SKY_FLAGS_ORIENTATION_SIGN = 0x04,
 			};
 
 			float grid_size[3];
@@ -410,12 +410,12 @@ private:
 			int32_t image_size[2];
 
 			int32_t world_offset[3];
-			uint32_t sky_mode;
+			uint32_t sky_flags;
 
 			int32_t scroll[3];
 			float sky_energy;
 
-			float sky_color[3];
+			float sky_color_or_orientation[3];
 			float y_mult;
 
 			uint32_t store_ambient_texture;

servers/rendering/renderer_rd/shaders/environment/sdfgi_integrate.glsl

@@ -49,9 +49,9 @@ layout(set = 1, binding = 1) uniform sampler linear_sampler_mipmaps;
 
 #define HISTORY_BITS 10
 
-#define SKY_MODE_DISABLED 0
-#define SKY_MODE_COLOR 1
-#define SKY_MODE_SKY 2
+#define SKY_FLAGS_MODE_COLOR 0x01
+#define SKY_FLAGS_MODE_SKY 0x02
+#define SKY_FLAGS_ORIENTATION_SIGN 0x04
 
 layout(push_constant, std430) uniform Params {
 	vec3 grid_size;
@@ -67,12 +67,12 @@ layout(push_constant, std430) uniform Params {
 	ivec2 image_size;
 
 	ivec3 world_offset;
-	uint sky_mode;
+	uint sky_flags;
 
 	ivec3 scroll;
 	float sky_energy;
 
-	vec3 sky_color;
+	vec3 sky_color_or_orientation;
 	float y_mult;
 
 	bool store_ambient_texture;
@@ -265,17 +265,22 @@ void main() {
 				}
 			}
 
-		} else if (params.sky_mode == SKY_MODE_SKY) {
+		} else if (bool(params.sky_flags & SKY_FLAGS_MODE_SKY)) {
+			// Reconstruct sky orientation as quaternion and rotate ray_dir before sampling.
+			float sky_sign = bool(params.sky_flags & SKY_FLAGS_ORIENTATION_SIGN) ? 1.0 : -1.0;
+			vec4 sky_quat = vec4(params.sky_color_or_orientation, sky_sign * sqrt(1.0 - dot(params.sky_color_or_orientation, params.sky_color_or_orientation)));
+			vec3 sky_dir = cross(sky_quat.xyz, ray_dir);
+			sky_dir = ray_dir + ((sky_dir * sky_quat.w) + cross(sky_quat.xyz, sky_dir)) * 2.0;
 #ifdef USE_CUBEMAP_ARRAY
-			light.rgb = textureLod(samplerCubeArray(sky_irradiance, linear_sampler_mipmaps), vec4(ray_dir, 0.0), 2.0).rgb; // Use second mipmap because we don't usually throw a lot of rays, so this compensates.
+			light.rgb = textureLod(samplerCubeArray(sky_irradiance, linear_sampler_mipmaps), vec4(sky_dir, 0.0), 2.0).rgb; // Use second mipmap because we don't usually throw a lot of rays, so this compensates.
 #else
-			light.rgb = textureLod(samplerCube(sky_irradiance, linear_sampler_mipmaps), ray_dir, 2.0).rgb; // Use second mipmap because we don't usually throw a lot of rays, so this compensates.
+			light.rgb = textureLod(samplerCube(sky_irradiance, linear_sampler_mipmaps), sky_dir, 2.0).rgb; // Use second mipmap because we don't usually throw a lot of rays, so this compensates.
 #endif
 			light.rgb *= params.sky_energy;
 			light.a = 0.0;
 
-		} else if (params.sky_mode == SKY_MODE_COLOR) {
-			light.rgb = params.sky_color;
+		} else if (bool(params.sky_flags & SKY_FLAGS_MODE_COLOR)) {
+			light.rgb = params.sky_color_or_orientation;
 			light.rgb *= params.sky_energy;
 			light.a = 0.0;
 		} else {