Add optional depth fog

doc/classes/Environment.xml

@@ -87,7 +87,18 @@
 			This is useful to simulate [url=https://en.wikipedia.org/wiki/Aerial_perspective]aerial perspective[/url] in large scenes with low density fog. However, it is not very useful for high-density fog, as the sky will shine through. When set to [code]1.0[/code], the fog color comes completely from the [Sky]. If set to [code]0.0[/code], aerial perspective is disabled.
 		</member>
 		<member name="fog_density" type="float" setter="set_fog_density" getter="get_fog_density" default="0.01">
-			The [i]exponential[/i] fog density to use. Higher values result in a more dense fog. Fog rendering is exponential as in real life.
+			The fog density to be used. This is demonstrated in different ways depending on the [member fog_mode] mode chosen:
+			[b]Exponential Fog Mode:[/b] Higher values result in denser fog. The fog rendering is exponential like in real life.
+			[b]Depth Fog mode:[/b] The maximum intensity of the deep fog, effect will appear in the distance (relative to the camera). At [code]1.0[/code] the fog will fully obscure the scene, at [code]0.0[/code] the fog will not be visible.
+		</member>
+		<member name="fog_depth_begin" type="float" setter="set_fog_depth_begin" getter="get_fog_depth_begin" default="10.0">
+			The fog's depth starting distance from the camera. Only available when [member fog_mode] is set to [constant FOG_MODE_DEPTH].
+		</member>
+		<member name="fog_depth_curve" type="float" setter="set_fog_depth_curve" getter="get_fog_depth_curve" default="1.0">
+			The fog depth's intensity curve. A number of presets are available in the Inspector by right-clicking the curve. Only available when [member fog_mode] is set to [constant FOG_MODE_DEPTH].
+		</member>
+		<member name="fog_depth_end" type="float" setter="set_fog_depth_end" getter="get_fog_depth_end" default="100.0">
+			The fog's depth end distance from the camera. If this value is set to [code]0[/code], it will be equal to the current camera's [member Camera3D.far] value. Only available when [member fog_mode] is set to [constant FOG_MODE_DEPTH].
 		</member>
 		<member name="fog_enabled" type="bool" setter="set_fog_enabled" getter="is_fog_enabled" default="false">
 			If [code]true[/code], fog effects are enabled.
@@ -104,6 +115,9 @@
 		<member name="fog_light_energy" type="float" setter="set_fog_light_energy" getter="get_fog_light_energy" default="1.0">
 			The fog's brightness. Higher values result in brighter fog.
 		</member>
+		<member name="fog_mode" type="int" setter="set_fog_mode" getter="get_fog_mode" enum="Environment.FogMode" default="0">
+			The fog mode. See [enum FogMode] for possible values.
+		</member>
 		<member name="fog_sky_affect" type="float" setter="set_fog_sky_affect" getter="get_fog_sky_affect" default="1.0">
 			The factor to use when affecting the sky with non-volumetric fog. [code]1.0[/code] means that fog can fully obscure the sky. Lower values reduce the impact of fog on sky rendering, with [code]0.0[/code] not affecting sky rendering at all.
 			[b]Note:[/b] [member fog_sky_affect] has no visual effect if [member fog_aerial_perspective] is [code]1.0[/code].
@@ -412,6 +426,12 @@
 		<constant name="GLOW_BLEND_MODE_MIX" value="4" enum="GlowBlendMode">
 			Mixes the glow with the underlying color to avoid increasing brightness as much while still maintaining a glow effect.
 		</constant>
+		<constant name="FOG_MODE_EXPONENTIAL" value="0" enum="FogMode">
+			Use a physically-based fog model defined primarily by fog density.
+		</constant>
+		<constant name="FOG_MODE_DEPTH" value="1" enum="FogMode">
+			Use a simple fog model defined by start and end positions and a custom curve. While not physically accurate, this model can be useful when you need more artistic control.
+		</constant>
 		<constant name="SDFGI_Y_SCALE_50_PERCENT" value="0" enum="SDFGIYScale">
 			Use 50% scale for SDFGI on the Y (vertical) axis. SDFGI cells will be twice as short as they are wide. This allows providing increased GI detail and reduced light leaking with thin floors and ceilings. This is usually the best choice for scenes that don't feature much verticality.
 		</constant>

doc/classes/RenderingServer.xml

@@ -1145,6 +1145,7 @@
 			<param index="7" name="height_density" type="float" />
 			<param index="8" name="aerial_perspective" type="float" />
 			<param index="9" name="sky_affect" type="float" />
+			<param index="10" name="fog_mode" type="int" enum="RenderingServer.EnvironmentFogMode" default="0" />
 			<description>
 				Configures fog for the specified environment RID. See [code]fog_*[/code] properties in [Environment] for more information.
 			</description>
@@ -4889,6 +4890,12 @@
 		<constant name="ENV_GLOW_BLEND_MODE_MIX" value="4" enum="EnvironmentGlowBlendMode">
 			Mixes the glow with the underlying color to avoid increasing brightness as much while still maintaining a glow effect.
 		</constant>
+		<constant name="ENV_FOG_MODE_EXPONENTIAL" value="0" enum="EnvironmentFogMode">
+			Use a physically-based fog model defined primarily by fog density.
+		</constant>
+		<constant name="ENV_FOG_MODE_DEPTH" value="1" enum="EnvironmentFogMode">
+			Use a simple fog model defined by start and end positions and a custom curve. While not physically accurate, this model can be useful when you need more artistic control.
+		</constant>
 		<constant name="ENV_TONE_MAPPER_LINEAR" value="0" enum="EnvironmentToneMapper">
 			Output color as they came in. This can cause bright lighting to look blown out, with noticeable clipping in the output colors.
 		</constant>

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -1642,8 +1642,12 @@ void RasterizerSceneGLES3::_setup_environment(const RenderDataGLES3 *p_render_da
 		}
 
 		scene_state.ubo.fog_enabled = environment_get_fog_enabled(p_render_data->environment);
+		scene_state.ubo.fog_mode = environment_get_fog_mode(p_render_data->environment);
 		scene_state.ubo.fog_density = environment_get_fog_density(p_render_data->environment);
 		scene_state.ubo.fog_height = environment_get_fog_height(p_render_data->environment);
+		scene_state.ubo.fog_depth_curve = environment_get_fog_depth_curve(p_render_data->environment);
+		scene_state.ubo.fog_depth_end = environment_get_fog_depth_end(p_render_data->environment) > 0.0 ? environment_get_fog_depth_end(p_render_data->environment) : scene_state.ubo.z_far;
+		scene_state.ubo.fog_depth_begin = MIN(environment_get_fog_depth_begin(p_render_data->environment), scene_state.ubo.fog_depth_end - 0.001);
 		scene_state.ubo.fog_height_density = environment_get_fog_height_density(p_render_data->environment);
 		scene_state.ubo.fog_aerial_perspective = environment_get_fog_aerial_perspective(p_render_data->environment);
 
@@ -2598,6 +2602,10 @@ void RasterizerSceneGLES3::render_scene(const Ref<RenderSceneBuffers> &p_render_
 		if (render_data.environment.is_null() || (render_data.environment.is_valid() && !environment_get_fog_enabled(render_data.environment))) {
 			spec_constant_base_flags |= SceneShaderGLES3::DISABLE_FOG;
 		}
+
+		if (render_data.environment.is_valid() && environment_get_fog_mode(render_data.environment) == RS::EnvironmentFogMode::ENV_FOG_MODE_DEPTH) {
+			spec_constant_base_flags |= SceneShaderGLES3::USE_DEPTH_FOG;
+		}
 	}
 	// Render Opaque Objects.
 	RenderListParameters render_list_params(render_list[RENDER_LIST_OPAQUE].elements.ptr(), render_list[RENDER_LIST_OPAQUE].elements.size(), reverse_cull, spec_constant_base_flags, use_wireframe);

drivers/gles3/rasterizer_scene_gles3.h

@@ -398,15 +398,21 @@ class RasterizerSceneGLES3 : public RendererSceneRender {
 			float IBL_exposure_normalization;
 
 			uint32_t fog_enabled;
+			uint32_t fog_mode;
 			float fog_density;
 			float fog_height;
+
 			float fog_height_density;
+			float fog_depth_curve;
+			float pad;
+			float fog_depth_begin;
 
 			float fog_light_color[3];
+			float fog_depth_end;
+
 			float fog_sun_scatter;
 
 			float shadow_bias;
-			float pad;
 			uint32_t camera_visible_layers;
 			bool pancake_shadows;
 		};

drivers/gles3/shaders/scene.glsl

@@ -13,6 +13,7 @@ DISABLE_LIGHT_DIRECTIONAL = false
 DISABLE_LIGHT_OMNI = false
 DISABLE_LIGHT_SPOT = false
 DISABLE_FOG = false
+USE_DEPTH_FOG = false
 USE_RADIANCE_MAP = true
 USE_LIGHTMAP = false
 USE_SH_LIGHTMAP = false
@@ -181,15 +182,21 @@ layout(std140) uniform SceneData { // ubo:2
 	float IBL_exposure_normalization;
 
 	bool fog_enabled;
+	uint fog_mode;
 	float fog_density;
 	float fog_height;
 	float fog_height_density;
 
+	float fog_depth_curve;
+	float pad;
+	float fog_depth_begin;
+
 	vec3 fog_light_color;
+	float fog_depth_end;
+
 	float fog_sun_scatter;
 
 	float shadow_bias;
-	float pad;
 	uint camera_visible_layers;
 	bool pancake_shadows;
 }
@@ -666,15 +673,21 @@ layout(std140) uniform SceneData { // ubo:2
 	float IBL_exposure_normalization;
 
 	bool fog_enabled;
+	uint fog_mode;
 	float fog_density;
 	float fog_height;
 	float fog_height_density;
 
+	float fog_depth_curve;
+	float pad;
+	float fog_depth_begin;
+
 	vec3 fog_light_color;
+	float fog_depth_end;
+
 	float fog_sun_scatter;
 
 	float shadow_bias;
-	float pad;
 	uint camera_visible_layers;
 	bool pancake_shadows;
 }
@@ -1250,7 +1263,14 @@ vec4 fog_process(vec3 vertex) {
 	}
 #endif // !DISABLE_LIGHT_DIRECTIONAL
 
-	float fog_amount = 1.0 - exp(min(0.0, -length(vertex) * scene_data.fog_density));
+	float fog_amount = 0.0;
+
+#ifdef USE_DEPTH_FOG
+	float fog_z = smoothstep(scene_data.fog_depth_begin, scene_data.fog_depth_end, length(vertex));
+	fog_amount = pow(fog_z, scene_data.fog_depth_curve) * scene_data.fog_density;
+#else
+	fog_amount = 1 - exp(min(0.0, -length(vertex) * scene_data.fog_density));
+#endif // USE_DEPTH_FOG
 
 	if (abs(scene_data.fog_height_density) >= 0.0001) {
 		float y = (scene_data.inv_view_matrix * vec4(vertex, 1.0)).y;

misc/extension_api_validation/4.2-stable.expected

@@ -147,3 +147,10 @@ GH-86661
 Validate extension JSON: Error: Field 'classes/Animation/methods/track_find_key/arguments': size changed value in new API, from 3 to 4.
 
 Added optional argument to track_find_key to avoid finding keys out of the animation range. Compatibility method registered.
+
+
+GH-84792
+--------
+Validate extension JSON: Error: Field 'classes/RenderingServer/methods/environment_set_fog/arguments': size changed value in new API, from 10 to 11.
+
+Added fog mode argument. Compatibility method registered.

scene/resources/environment.cpp

@@ -766,6 +766,21 @@ bool Environment::is_fog_enabled() const {
 	return fog_enabled;
 }
 
+void Environment::set_fog_mode(FogMode p_mode) {
+	if (fog_mode != p_mode && p_mode == FogMode::FOG_MODE_EXPONENTIAL) {
+		set_fog_density(0.01);
+	} else {
+		set_fog_density(1.0);
+	}
+	fog_mode = p_mode;
+	_update_fog();
+	notify_property_list_changed();
+}
+
+Environment::FogMode Environment::get_fog_mode() const {
+	return fog_mode;
+}
+
 void Environment::set_fog_light_color(const Color &p_light_color) {
 	fog_light_color = p_light_color;
 	_update_fog();
@@ -837,7 +852,51 @@ void Environment::_update_fog() {
 			fog_height,
 			fog_height_density,
 			fog_aerial_perspective,
-			fog_sky_affect);
+			fog_sky_affect,
+			RS::EnvironmentFogMode(fog_mode));
+}
+
+// Depth Fog
+
+void Environment::set_fog_depth_curve(float p_curve) {
+	fog_depth_curve = p_curve;
+	_update_fog_depth();
+}
+
+float Environment::get_fog_depth_curve() const {
+	return fog_depth_curve;
+}
+
+void Environment::set_fog_depth_begin(float p_begin) {
+	fog_depth_begin = p_begin;
+	if (fog_depth_begin > fog_depth_end) {
+		set_fog_depth_end(fog_depth_begin);
+	}
+	_update_fog_depth();
+}
+
+float Environment::get_fog_depth_begin() const {
+	return fog_depth_begin;
+}
+
+void Environment::set_fog_depth_end(float p_end) {
+	fog_depth_end = p_end;
+	if (fog_depth_end < fog_depth_begin) {
+		set_fog_depth_begin(fog_depth_end);
+	}
+	_update_fog_depth();
+}
+
+float Environment::get_fog_depth_end() const {
+	return fog_depth_end;
+}
+
+void Environment::_update_fog_depth() {
+	RS::get_singleton()->environment_set_fog_depth(
+			environment,
+			fog_depth_curve,
+			fog_depth_begin,
+			fog_depth_end);
 }
 
 // Volumetric Fog
@@ -1040,6 +1099,12 @@ void Environment::_validate_property(PropertyInfo &p_property) const {
 		}
 	}
 
+	if (p_property.name == "fog_depth_curve" || p_property.name == "fog_depth_begin" || p_property.name == "fog_depth_end") {
+		if (fog_mode == FOG_MODE_EXPONENTIAL) {
+			p_property.usage = PROPERTY_USAGE_NO_EDITOR;
+		}
+	}
+
 	if (p_property.name == "ambient_light_color" || p_property.name == "ambient_light_energy") {
 		if (ambient_source == AMBIENT_SOURCE_DISABLED) {
 			p_property.usage = PROPERTY_USAGE_NO_EDITOR;
@@ -1377,6 +1442,8 @@ void Environment::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("set_fog_enabled", "enabled"), &Environment::set_fog_enabled);
 	ClassDB::bind_method(D_METHOD("is_fog_enabled"), &Environment::is_fog_enabled);
+	ClassDB::bind_method(D_METHOD("set_fog_mode", "mode"), &Environment::set_fog_mode);
+	ClassDB::bind_method(D_METHOD("get_fog_mode"), &Environment::get_fog_mode);
 	ClassDB::bind_method(D_METHOD("set_fog_light_color", "light_color"), &Environment::set_fog_light_color);
 	ClassDB::bind_method(D_METHOD("get_fog_light_color"), &Environment::get_fog_light_color);
 	ClassDB::bind_method(D_METHOD("set_fog_light_energy", "light_energy"), &Environment::set_fog_light_energy);
@@ -1399,8 +1466,16 @@ void Environment::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_fog_sky_affect", "sky_affect"), &Environment::set_fog_sky_affect);
 	ClassDB::bind_method(D_METHOD("get_fog_sky_affect"), &Environment::get_fog_sky_affect);
 
+	ClassDB::bind_method(D_METHOD("set_fog_depth_curve", "curve"), &Environment::set_fog_depth_curve);
+	ClassDB::bind_method(D_METHOD("get_fog_depth_curve"), &Environment::get_fog_depth_curve);
+	ClassDB::bind_method(D_METHOD("set_fog_depth_begin", "begin"), &Environment::set_fog_depth_begin);
+	ClassDB::bind_method(D_METHOD("get_fog_depth_begin"), &Environment::get_fog_depth_begin);
+	ClassDB::bind_method(D_METHOD("set_fog_depth_end", "end"), &Environment::set_fog_depth_end);
+	ClassDB::bind_method(D_METHOD("get_fog_depth_end"), &Environment::get_fog_depth_end);
+
 	ADD_GROUP("Fog", "fog_");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "fog_enabled"), "set_fog_enabled", "is_fog_enabled");
+	ADD_PROPERTY(PropertyInfo(Variant::INT, "fog_mode", PROPERTY_HINT_ENUM, "Exponential,Depth"), "set_fog_mode", "get_fog_mode");
 	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "fog_light_color", PROPERTY_HINT_COLOR_NO_ALPHA), "set_fog_light_color", "get_fog_light_color");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_light_energy", PROPERTY_HINT_RANGE, "0,16,0.01,or_greater"), "set_fog_light_energy", "get_fog_light_energy");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_sun_scatter", PROPERTY_HINT_RANGE, "0,1,0.01,or_greater"), "set_fog_sun_scatter", "get_fog_sun_scatter");
@@ -1411,6 +1486,10 @@ void Environment::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_height", PROPERTY_HINT_RANGE, "-1024,1024,0.01,or_less,or_greater,suffix:m"), "set_fog_height", "get_fog_height");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_height_density", PROPERTY_HINT_RANGE, "-16,16,0.0001,or_less,or_greater"), "set_fog_height_density", "get_fog_height_density");
 
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_depth_curve", PROPERTY_HINT_EXP_EASING), "set_fog_depth_curve", "get_fog_depth_curve");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_depth_begin", PROPERTY_HINT_RANGE, "0,4000,0.1,or_greater,or_less,suffix:m"), "set_fog_depth_begin", "get_fog_depth_begin");
+	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "fog_depth_end", PROPERTY_HINT_RANGE, "0,4000,0.1,or_greater,or_less,suffix:m"), "set_fog_depth_end", "get_fog_depth_end");
+
 	ClassDB::bind_method(D_METHOD("set_volumetric_fog_enabled", "enabled"), &Environment::set_volumetric_fog_enabled);
 	ClassDB::bind_method(D_METHOD("is_volumetric_fog_enabled"), &Environment::is_volumetric_fog_enabled);
 	ClassDB::bind_method(D_METHOD("set_volumetric_fog_emission", "color"), &Environment::set_volumetric_fog_emission);
@@ -1504,6 +1583,9 @@ void Environment::_bind_methods() {
 	BIND_ENUM_CONSTANT(GLOW_BLEND_MODE_REPLACE);
 	BIND_ENUM_CONSTANT(GLOW_BLEND_MODE_MIX);
 
+	BIND_ENUM_CONSTANT(FOG_MODE_EXPONENTIAL);
+	BIND_ENUM_CONSTANT(FOG_MODE_DEPTH);
+
 	BIND_ENUM_CONSTANT(SDFGI_Y_SCALE_50_PERCENT);
 	BIND_ENUM_CONSTANT(SDFGI_Y_SCALE_75_PERCENT);
 	BIND_ENUM_CONSTANT(SDFGI_Y_SCALE_100_PERCENT);

scene/resources/environment.h

@@ -75,6 +75,11 @@ class Environment : public Resource {
 		SDFGI_Y_SCALE_100_PERCENT,
 	};
 
+	enum FogMode {
+		FOG_MODE_EXPONENTIAL,
+		FOG_MODE_DEPTH,
+	};
+
 	enum GlowBlendMode {
 		GLOW_BLEND_MODE_ADDITIVE,
 		GLOW_BLEND_MODE_SCREEN,
@@ -172,6 +177,7 @@ class Environment : public Resource {
 
 	// Fog
 	bool fog_enabled = false;
+	FogMode fog_mode = FOG_MODE_EXPONENTIAL;
 	Color fog_light_color = Color(0.518, 0.553, 0.608);
 	float fog_light_energy = 1.0;
 	float fog_sun_scatter = 0.0;
@@ -183,6 +189,13 @@ class Environment : public Resource {
 
 	void _update_fog();
 
+	// Depth Fog
+	float fog_depth_curve = 1.0;
+	float fog_depth_begin = 10.0;
+	float fog_depth_end = 100.0;
+
+	void _update_fog_depth();
+
 	// Volumetric Fog
 	bool volumetric_fog_enabled = false;
 	float volumetric_fog_density = 0.05;
@@ -361,6 +374,8 @@ class Environment : public Resource {
 
 	void set_fog_enabled(bool p_enabled);
 	bool is_fog_enabled() const;
+	void set_fog_mode(FogMode p_mode);
+	FogMode get_fog_mode() const;
 	void set_fog_light_color(const Color &p_light_color);
 	Color get_fog_light_color() const;
 	void set_fog_light_energy(float p_amount);
@@ -379,6 +394,14 @@ class Environment : public Resource {
 	void set_fog_sky_affect(float p_sky_affect);
 	float get_fog_sky_affect() const;
 
+	// Depth Fog
+	void set_fog_depth_curve(float p_curve);
+	float get_fog_depth_curve() const;
+	void set_fog_depth_begin(float p_begin);
+	float get_fog_depth_begin() const;
+	void set_fog_depth_end(float p_end);
+	float get_fog_depth_end() const;
+
 	// Volumetric Fog
 	void set_volumetric_fog_enabled(bool p_enable);
 	bool is_volumetric_fog_enabled() const;
@@ -429,5 +452,6 @@ VARIANT_ENUM_CAST(Environment::ReflectionSource)
 VARIANT_ENUM_CAST(Environment::ToneMapper)
 VARIANT_ENUM_CAST(Environment::SDFGIYScale)
 VARIANT_ENUM_CAST(Environment::GlowBlendMode)
+VARIANT_ENUM_CAST(Environment::FogMode)
 
 #endif // ENVIRONMENT_H