Add aerial perspective to fixed fog

12 files changed, 55 insertions, 25 deletions

diff --git a/servers/rendering/rasterizer.h b/servers/rendering/rasterizer.h
index 84c04f34b6..cecd2f2212 100644
--- a/servers/rendering/rasterizer.h
+++ b/servers/rendering/rasterizer.h
@@ -111,7 +111,7 @@ public:
 
 	virtual void environment_set_adjustment(RID p_env, bool p_enable, float p_brightness, float p_contrast, float p_saturation, RID p_ramp) = 0;
 
-	virtual void environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density) = 0;
+	virtual void environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density, float p_aerial_perspective) = 0;
 
 	virtual Ref<Image> environment_bake_panorama(RID p_env, bool p_bake_irradiance, const Size2i &p_size) = 0;
 
diff --git a/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.cpp b/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.cpp
index ac028e93f1..fe275914f0 100644
--- a/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.cpp
+++ b/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.cpp
@@ -1335,6 +1335,7 @@ void RasterizerSceneHighEndRD::_setup_environment(RID p_environment, RID p_rende
 		if (scene_state.ubo.fog_height_density >= 0.0001) {
 			scene_state.ubo.fog_height_density = 1.0 / scene_state.ubo.fog_height_density;
 		}
+		scene_state.ubo.fog_aerial_perspective = environment_get_fog_aerial_perspective(p_environment);
 
 		Color fog_color = environment_get_fog_light_color(p_environment).to_linear();
 		float fog_energy = environment_get_fog_light_energy(p_environment);
diff --git a/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.h b/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.h
index 4c89928c95..566022ae5b 100644
--- a/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.h
+++ b/servers/rendering/rasterizer_rd/rasterizer_scene_high_end_rd.h
@@ -308,12 +308,6 @@ class RasterizerSceneHighEndRD : public RasterizerSceneRD {
 			float viewport_size[2];
 			float screen_pixel_size[2];
 
-			float time;
-			float reflection_multiplier;
-
-			uint32_t pancake_shadows;
-			uint32_t pad;
-
 			float directional_penumbra_shadow_kernel[128]; //32 vec4s
 			float directional_soft_shadow_kernel[128];
 			float penumbra_shadow_kernel[128];
@@ -366,7 +360,6 @@ class RasterizerSceneHighEndRD : public RasterizerSceneRD {
 			uint32_t volumetric_fog_pad;
 
 			// Fog
-
 			uint32_t fog_enabled;
 			float fog_density;
 			float fog_height;
@@ -374,6 +367,13 @@ class RasterizerSceneHighEndRD : public RasterizerSceneRD {
 
 			float fog_light_color[3];
 			float fog_sun_scatter;
+
+			float fog_aerial_perspective;
+
+			float time;
+			float reflection_multiplier;
+
+			uint32_t pancake_shadows;
 		};
 
 		UBO ubo;
diff --git a/servers/rendering/rasterizer_rd/rasterizer_scene_rd.cpp b/servers/rendering/rasterizer_rd/rasterizer_scene_rd.cpp
index 934330cc9b..ce823b7198 100644
--- a/servers/rendering/rasterizer_rd/rasterizer_scene_rd.cpp
+++ b/servers/rendering/rasterizer_rd/rasterizer_scene_rd.cpp
@@ -2322,6 +2322,7 @@ void RasterizerSceneRD::_setup_sky(RID p_environment, RID p_render_buffers, cons
 	sky_scene_state.ubo.z_far = p_projection.get_z_far();
 	sky_scene_state.ubo.fog_enabled = environment_is_fog_enabled(p_environment);
 	sky_scene_state.ubo.fog_density = environment_get_fog_density(p_environment);
+	sky_scene_state.ubo.fog_aerial_perspective = environment_get_fog_aerial_perspective(p_environment);
 	Color fog_color = environment_get_fog_light_color(p_environment).to_linear();
 	float fog_energy = environment_get_fog_light_energy(p_environment);
 	sky_scene_state.ubo.fog_light_color[0] = fog_color.r * fog_energy;
@@ -2971,7 +2972,7 @@ void RasterizerSceneRD::environment_set_sdfgi(RID p_env, bool p_enable, RS::Envi
 	env->sdfgi_y_scale = p_y_scale;
 }
 
-void RasterizerSceneRD::environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density) {
+void RasterizerSceneRD::environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density, float p_fog_aerial_perspective) {
 	Environment *env = environment_owner.getornull(p_env);
 	ERR_FAIL_COND(!env);
 
@@ -2982,6 +2983,7 @@ void RasterizerSceneRD::environment_set_fog(RID p_env, bool p_enable, const Colo
 	env->fog_density = p_density;
 	env->fog_height = p_height;
 	env->fog_height_density = p_height_density;
+	env->fog_aerial_perspective = p_fog_aerial_perspective;
 }
 
 bool RasterizerSceneRD::environment_is_fog_enabled(RID p_env) const {
@@ -3022,6 +3024,12 @@ float RasterizerSceneRD::environment_get_fog_height_density(RID p_env) const {
 	return env->fog_height_density;
 }
 
+float RasterizerSceneRD::environment_get_fog_aerial_perspective(RID p_env) const {
+	const Environment *env = environment_owner.getornull(p_env);
+	ERR_FAIL_COND_V(!env, 0);
+	return env->fog_aerial_perspective;
+}
+
 void RasterizerSceneRD::environment_set_volumetric_fog(RID p_env, bool p_enable, float p_density, const Color &p_light, float p_light_energy, float p_length, float p_detail_spread, float p_gi_inject, RenderingServer::EnvVolumetricFogShadowFilter p_shadow_filter) {
 	Environment *env = environment_owner.getornull(p_env);
 	ERR_FAIL_COND(!env);
diff --git a/servers/rendering/rasterizer_rd/rasterizer_scene_rd.h b/servers/rendering/rasterizer_rd/rasterizer_scene_rd.h
index 0e7e56716b..50647d54bf 100644
--- a/servers/rendering/rasterizer_rd/rasterizer_scene_rd.h
+++ b/servers/rendering/rasterizer_rd/rasterizer_scene_rd.h
@@ -67,7 +67,8 @@ protected:
 			uint32_t volumetric_fog_enabled;
 			float volumetric_fog_inv_length;
 			float volumetric_fog_detail_spread;
-			uint32_t volumetric_fog_pad;
+
+			float fog_aerial_perspective;
 
 			float fog_light_color[3];
 			float fog_sun_scatter;
@@ -706,6 +707,7 @@ private:
 		float fog_density = 0.001;
 		float fog_height = 0.0;
 		float fog_height_density = 0.0; //can be negative to invert effect
+		float fog_aerial_perspective = 0.0;
 
 		/// Volumetric Fog
 		///
@@ -1534,7 +1536,7 @@ public:
 	void environment_glow_set_use_bicubic_upscale(bool p_enable);
 	void environment_glow_set_use_high_quality(bool p_enable);
 
-	void environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density);
+	void environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density, float p_aerial_perspective);
 	bool environment_is_fog_enabled(RID p_env) const;
 	Color environment_get_fog_light_color(RID p_env) const;
 	float environment_get_fog_light_energy(RID p_env) const;
@@ -1542,6 +1544,7 @@ public:
 	float environment_get_fog_density(RID p_env) const;
 	float environment_get_fog_height(RID p_env) const;
 	float environment_get_fog_height_density(RID p_env) const;
+	float environment_get_fog_aerial_perspective(RID p_env) const;
 
 	void environment_set_volumetric_fog(RID p_env, bool p_enable, float p_density, const Color &p_light, float p_light_energy, float p_length, float p_detail_spread, float p_gi_inject, RS::EnvVolumetricFogShadowFilter p_shadow_filter);
 
diff --git a/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl b/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl
index be34473892..ec199c0d0e 100644
--- a/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/scene_high_end.glsl
@@ -1621,6 +1621,22 @@ vec4 volumetric_fog_process(vec2 screen_uv, float z) {
 vec4 fog_process(vec3 vertex) {
 	vec3 fog_color = scene_data.fog_light_color;
 
+	if (scene_data.fog_aerial_perspective > 0.0) {
+		vec3 sky_fog_color = vec3(0.0);
+		vec3 cube_view = scene_data.radiance_inverse_xform * vertex;
+		// mip_level always reads from the second mipmap and higher so the fog is always slightly blurred
+		float mip_level = mix(1.0 / MAX_ROUGHNESS_LOD, 1.0, 1.0 - (abs(vertex.z) - scene_data.z_near) / (scene_data.z_far - scene_data.z_near));
+#ifdef USE_RADIANCE_CUBEMAP_ARRAY
+		float lod, blend;
+		blend = modf(mip_level * MAX_ROUGHNESS_LOD, lod);
+		sky_fog_color = texture(samplerCubeArray(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), vec4(cube_view, lod)).rgb;
+		sky_fog_color = mix(sky_fog_color, texture(samplerCubeArray(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), vec4(cube_view, lod + 1)).rgb, blend);
+#else
+		sky_fog_color = textureLod(samplerCube(radiance_cubemap, material_samplers[SAMPLER_LINEAR_WITH_MIPMAPS_CLAMP]), cube_view, mip_level * MAX_ROUGHNESS_LOD).rgb;
+#endif //USE_RADIANCE_CUBEMAP_ARRAY
+		fog_color = mix(fog_color, sky_fog_color, scene_data.fog_aerial_perspective);
+	}
+
 	if (scene_data.fog_sun_scatter > 0.001) {
 		vec4 sun_scatter = vec4(0.0);
 		float sun_total = 0.0;
diff --git a/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl b/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl
index 0cc2b90c53..e29a490ca1 100644
--- a/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/scene_high_end_inc.glsl
@@ -43,12 +43,6 @@ layout(set = 0, binding = 3, std140) uniform SceneData {
 	vec2 viewport_size;
 	vec2 screen_pixel_size;
 
-	float time;
-	float reflection_multiplier; // one normally, zero when rendering reflections
-
-	bool pancake_shadows;
-	uint pad;
-
 	//use vec4s because std140 doesnt play nice with vec2s, z and w are wasted
 	vec4 directional_penumbra_shadow_kernel[32];
 	vec4 directional_soft_shadow_kernel[32];
@@ -108,6 +102,13 @@ layout(set = 0, binding = 3, std140) uniform SceneData {
 
 	vec3 fog_light_color;
 	float fog_sun_scatter;
+
+	float fog_aerial_perspective;
+
+	float time;
+	float reflection_multiplier; // one normally, zero when rendering reflections
+
+	bool pancake_shadows;
 }
 
 scene_data;
diff --git a/servers/rendering/rasterizer_rd/shaders/sky.glsl b/servers/rendering/rasterizer_rd/shaders/sky.glsl
index 7711f683ae..f1a31d3486 100644
--- a/servers/rendering/rasterizer_rd/shaders/sky.glsl
+++ b/servers/rendering/rasterizer_rd/shaders/sky.glsl
@@ -62,7 +62,8 @@ layout(set = 0, binding = 2, std140) uniform SceneData {
 	bool volumetric_fog_enabled;
 	float volumetric_fog_inv_length;
 	float volumetric_fog_detail_spread;
-	uint volumetric_fog_pad;
+
+	float fog_aerial_perspective;
 
 	vec3 fog_light_color;
 	float fog_sun_scatter;
@@ -140,8 +141,8 @@ vec4 volumetric_fog_process(vec2 screen_uv) {
 	return texture(sampler3D(volumetric_fog_texture, material_samplers[SAMPLER_LINEAR_CLAMP]), fog_pos);
 }
 
-vec4 fog_process(vec3 view) {
-	vec3 fog_color = scene_data.fog_light_color;
+vec4 fog_process(vec3 view, vec3 sky_color) {
+	vec3 fog_color = mix(scene_data.fog_light_color, sky_color, scene_data.fog_aerial_perspective);
 
 	if (scene_data.fog_sun_scatter > 0.001) {
 		vec4 sun_scatter = vec4(0.0);
@@ -225,7 +226,7 @@ FRAGMENT_SHADER_CODE
 
 	// Draw "fixed" fog before volumetric fog to ensure volumetric fog can appear in front of the sky.
 	if (scene_data.fog_enabled) {
-		vec4 fog = fog_process(cube_normal);
+		vec4 fog = fog_process(cube_normal, frag_color.rgb);
 		frag_color.rgb = mix(frag_color.rgb, fog.rgb, fog.a);
 	}
 
diff --git a/servers/rendering/rendering_server_raster.h b/servers/rendering/rendering_server_raster.h
index afb3d6f46f..04c16cfd4a 100644
--- a/servers/rendering/rendering_server_raster.h
+++ b/servers/rendering/rendering_server_raster.h
@@ -589,7 +589,7 @@ public:
 
 	BIND6(environment_set_adjustment, RID, bool, float, float, float, RID)
 
-	BIND8(environment_set_fog, RID, bool, const Color &, float, float, float, float, float)
+	BIND9(environment_set_fog, RID, bool, const Color &, float, float, float, float, float, float)
 	BIND9(environment_set_volumetric_fog, RID, bool, float, const Color &, float, float, float, float, EnvVolumetricFogShadowFilter)
 
 	BIND2(environment_set_volumetric_fog_volume_size, int, int)
diff --git a/servers/rendering/rendering_server_wrap_mt.h b/servers/rendering/rendering_server_wrap_mt.h
index 910acd74cb..c490be4a6b 100644
--- a/servers/rendering/rendering_server_wrap_mt.h
+++ b/servers/rendering/rendering_server_wrap_mt.h
@@ -500,7 +500,7 @@ public:
 
 	FUNC6(environment_set_adjustment, RID, bool, float, float, float, RID)
 
-	FUNC8(environment_set_fog, RID, bool, const Color &, float, float, float, float, float)
+	FUNC9(environment_set_fog, RID, bool, const Color &, float, float, float, float, float, float)
 
 	FUNC9(environment_set_volumetric_fog, RID, bool, float, const Color &, float, float, float, float, EnvVolumetricFogShadowFilter)
 
diff --git a/servers/rendering_server.cpp b/servers/rendering_server.cpp
index 9434e377f8..fa0834e210 100644
--- a/servers/rendering_server.cpp
+++ b/servers/rendering_server.cpp
@@ -1752,7 +1752,7 @@ void RenderingServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("environment_set_adjustment", "env", "enable", "brightness", "contrast", "saturation", "ramp"), &RenderingServer::environment_set_adjustment);
 	ClassDB::bind_method(D_METHOD("environment_set_ssr", "env", "enable", "max_steps", "fade_in", "fade_out", "depth_tolerance"), &RenderingServer::environment_set_ssr);
 	ClassDB::bind_method(D_METHOD("environment_set_ssao", "env", "enable", "radius", "intensity", "bias", "light_affect", "ao_channel_affect", "blur", "bilateral_sharpness"), &RenderingServer::environment_set_ssao);
-	ClassDB::bind_method(D_METHOD("environment_set_fog", "env", "enable", "light_color", "light_energy", "sun_scatter", "density", "height", "height_density"), &RenderingServer::environment_set_fog);
+	ClassDB::bind_method(D_METHOD("environment_set_fog", "env", "enable", "light_color", "light_energy", "sun_scatter", "density", "height", "height_density", "aerial_perspective"), &RenderingServer::environment_set_fog);
 
 	ClassDB::bind_method(D_METHOD("scenario_create"), &RenderingServer::scenario_create);
 	ClassDB::bind_method(D_METHOD("scenario_set_debug", "scenario", "debug_mode"), &RenderingServer::scenario_set_debug);
diff --git a/servers/rendering_server.h b/servers/rendering_server.h
index 7680dc1390..dfb3dad166 100644
--- a/servers/rendering_server.h
+++ b/servers/rendering_server.h
@@ -914,7 +914,7 @@ public:
 
 	virtual void environment_set_sdfgi_frames_to_converge(EnvironmentSDFGIFramesToConverge p_frames) = 0;
 
-	virtual void environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density) = 0;
+	virtual void environment_set_fog(RID p_env, bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density, float p_aerial_perspective) = 0;
 
 	enum EnvVolumetricFogShadowFilter {
 		ENV_VOLUMETRIC_FOG_SHADOW_FILTER_DISABLED,