Add white, contrast, and future HDR support to the AgX tonemapper.

doc/classes/Environment.xml

@@ -315,6 +315,13 @@
 		<member name="ssr_max_steps" type="int" setter="set_ssr_max_steps" getter="get_ssr_max_steps" default="64">
 			The maximum number of steps for screen-space reflections. Higher values are slower.
 		</member>
+		<member name="tonemap_agx_contrast" type="float" setter="set_tonemap_agx_contrast" getter="get_tonemap_agx_contrast" default="1.25">
+			Increasing [member tonemap_agx_contrast] will make dark values darker and bright values brighter. Produces a higher quality result than [member adjustment_contrast] without any additional performance cost, but is only available when using the [constant TONE_MAPPER_AGX] tonemapper.
+		</member>
+		<member name="tonemap_agx_white" type="float" setter="set_tonemap_agx_white" getter="get_tonemap_agx_white" default="16.29">
+			The white reference value for tonemapping, which indicates where bright white is located in the scale of values provided to the tonemapper. For photorealistic lighting, it is recommended to set [member tonemap_agx_white] to at least [code]6.0[/code]. Higher values result in less blown out highlights, but may make the scene appear lower contrast. [member tonemap_agx_white] is the same as [member tonemap_white], but is only effective with the [constant TONE_MAPPER_AGX] tonemapper. See also [member tonemap_exposure].
+			[b]Note:[/b] When using the Mobile renderer with [member Viewport.use_hdr_2d] disabled, [member tonemap_agx_white] is ignored and a white value of [code]2.0[/code] will always be used instead.
+		</member>
 		<member name="tonemap_exposure" type="float" setter="set_tonemap_exposure" getter="get_tonemap_exposure" default="1.0">
 			Adjusts the brightness of values before they are provided to the tonemapper. Higher [member tonemap_exposure] values result in a brighter image. See also [member tonemap_white].
 			[b]Note:[/b] Values provided to the tonemapper will also be multiplied by [code]2.0[/code] and [code]1.8[/code] for [constant TONE_MAPPER_FILMIC] and [constant TONE_MAPPER_ACES] respectively to produce a similar apparent brightness as [constant TONE_MAPPER_LINEAR].
@@ -323,8 +330,8 @@
 			The tonemapping mode to use. Tonemapping is the process that "converts" HDR values to be suitable for rendering on an LDR display. (Godot doesn't support rendering on HDR displays yet.)
 		</member>
 		<member name="tonemap_white" type="float" setter="set_tonemap_white" getter="get_tonemap_white" default="1.0">
-			The white reference value for tonemapping, which indicates where bright white is located in the scale of values provided to the tonemapper. For photorealistic lighting, recommended values are between [code]6.0[/code] and [code]8.0[/code]. Higher values result in less blown out highlights, but may make the scene appear lower contrast. See also [member tonemap_exposure].
-			[b]Note:[/b] [member tonemap_white] is ignored when using [constant TONE_MAPPER_LINEAR] or [constant TONE_MAPPER_AGX].
+			The white reference value for tonemapping, which indicates where bright white is located in the scale of values provided to the tonemapper. For photorealistic lighting, it is recommended to set [member tonemap_white] to at least [code]6.0[/code]. Higher values result in less blown out highlights, but may make the scene appear lower contrast. [member tonemap_agx_white] will be used instead when using the [constant TONE_MAPPER_AGX] tonemapper. See also [member tonemap_exposure].
+			[b]Note:[/b] [member tonemap_white] must be set to [code]2.0[/code] or lower on the Mobile renderer to produce bright images.
 		</member>
 		<member name="volumetric_fog_albedo" type="Color" setter="set_volumetric_fog_albedo" getter="get_volumetric_fog_albedo" default="Color(1, 1, 1, 1)">
 			The [Color] of the volumetric fog when interacting with lights. Mist and fog have an albedo close to [code]Color(1, 1, 1, 1)[/code] while smoke has a darker albedo.
@@ -431,8 +438,7 @@
 			[b]Note:[/b] This tonemapping operator is called "ACES Fitted" in Godot 3.x.
 		</constant>
 		<constant name="TONE_MAPPER_AGX" value="4" enum="ToneMapper">
-			Uses a film-like tonemapping curve and desaturates bright values for a more realistic appearance. Better than other tonemappers at maintaining the hue of colors as they become brighter. The slowest tonemapping option.
-			[b]Note:[/b] [member tonemap_white] is fixed at a value of [code]16.29[/code], which makes [constant TONE_MAPPER_AGX] unsuitable for use with the Mobile rendering method.
+			Uses an adjustable film-like tonemapping curve and desaturates bright values for a more realistic appearance. Better than other tonemappers at maintaining the hue of colors as they become brighter. The slowest tonemapping option.
 		</constant>
 		<constant name="GLOW_BLEND_MODE_ADDITIVE" value="0" enum="GlowBlendMode">
 			Adds the glow effect to the scene.

doc/classes/RenderingServer.xml

@@ -1523,6 +1523,14 @@
 				Sets the variables to be used with the "tonemap" post-process effect. See [Environment] for more details.
 			</description>
 		</method>
+		<method name="environment_set_tonemap_agx_contrast">
+			<return type="void" />
+			<param index="0" name="env" type="RID" />
+			<param index="1" name="agx_contrast" type="float" />
+			<description>
+				See [member Environment.tonemap_agx_contrast] for more details.
+			</description>
+		</method>
 		<method name="environment_set_volumetric_fog">
 			<return type="void" />
 			<param index="0" name="env" type="RID" />
@@ -5509,8 +5517,7 @@
 			[b]Note:[/b] This tonemapping operator is called "ACES Fitted" in Godot 3.x.
 		</constant>
 		<constant name="ENV_TONE_MAPPER_AGX" value="4" enum="EnvironmentToneMapper">
-			Uses a film-like tonemapping curve and desaturates bright values for a more realistic appearance. Better than other tonemappers at maintaining the hue of colors as they become brighter. The slowest tonemapping option.
-			[b]Note:[/b] [member Environment.tonemap_white] is fixed at a value of [code]16.29[/code], which makes [constant ENV_TONE_MAPPER_AGX] unsuitable for use with the Mobile rendering method.
+			Uses an adjustable film-like tonemapping curve and desaturates bright values for a more realistic appearance. Better than other tonemappers at maintaining the hue of colors as they become brighter. The slowest tonemapping option.
 		</constant>
 		<constant name="ENV_SSR_ROUGHNESS_QUALITY_DISABLED" value="0" enum="EnvironmentSSRRoughnessQuality">
 			Lowest quality of roughness filter for screen-space reflections. Rough materials will not have blurrier screen-space reflections compared to smooth (non-rough) materials. This is the fastest option.

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -2380,9 +2380,12 @@ void RasterizerSceneGLES3::render_scene(const Ref<RenderSceneBuffers> &p_render_
 		}
 
 		tonemap_ubo.exposure = environment_get_exposure(render_data.environment);
-		tonemap_ubo.white = environment_get_white(render_data.environment);
 		tonemap_ubo.tonemapper = int32_t(environment_get_tone_mapper(render_data.environment));
-
+		RendererEnvironmentStorage::TonemapParameters params = environment_get_tonemap_parameters(render_data.environment, false);
+		tonemap_ubo.tonemapper_params[0] = params.tonemapper_params[0];
+		tonemap_ubo.tonemapper_params[1] = params.tonemapper_params[1];
+		tonemap_ubo.tonemapper_params[2] = params.tonemapper_params[2];
+		tonemap_ubo.tonemapper_params[3] = params.tonemapper_params[3];
 		tonemap_ubo.brightness = environment_get_adjustments_brightness(render_data.environment);
 		tonemap_ubo.contrast = environment_get_adjustments_contrast(render_data.environment);
 		tonemap_ubo.saturation = environment_get_adjustments_saturation(render_data.environment);
@@ -2840,7 +2843,7 @@ void RasterizerSceneGLES3::_render_post_processing(const RenderDataGLES3 *p_rend
 		glow_hdr_bleed_threshold = environment_get_glow_hdr_bleed_threshold(p_render_data->environment);
 		glow_hdr_bleed_scale = environment_get_glow_hdr_bleed_scale(p_render_data->environment);
 		glow_hdr_luminance_cap = environment_get_glow_hdr_luminance_cap(p_render_data->environment);
-		srgb_white = environment_get_white(p_render_data->environment);
+		srgb_white = environment_get_white(p_render_data->environment, false);
 	}
 
 	if (glow_enabled) {

drivers/gles3/rasterizer_scene_gles3.h

@@ -449,14 +449,14 @@ class RasterizerSceneGLES3 : public RendererSceneRender {
 
 		struct TonemapUBO {
 			float exposure = 1.0;
-			float white = 1.0;
 			int32_t tonemapper = 0;
 			int32_t pad = 0;
-
 			int32_t pad2 = 0;
+			float tonemapper_params[4] = { 0.0, 0.0, 0.0, 0.0 };
 			float brightness = 1.0;
 			float contrast = 1.0;
 			float saturation = 1.0;
+			int32_t pad3 = 0;
 		};
 		static_assert(sizeof(TonemapUBO) % 16 == 0, "Tonemap UBO size must be a multiple of 16 bytes");
 

drivers/gles3/shaders/effects/post.glsl

@@ -164,7 +164,7 @@ void main() {
 	color.rgb *= s4ao(uv_interp); // The USE_SSAO_X controls the number of samples.
 #endif
 
-	color.rgb = apply_tonemapping(color.rgb, white);
+	color.rgb = apply_tonemapping(color.rgb);
 
 #ifdef USE_BCS
 	// Apply brightness:

drivers/gles3/shaders/scene.glsl

@@ -2534,7 +2534,7 @@ void main() {
 	// Tonemap before writing as we are writing to an sRGB framebuffer
 	frag_color.rgb *= exposure;
 #ifdef APPLY_TONEMAPPING
-	frag_color.rgb = apply_tonemapping(frag_color.rgb, white);
+	frag_color.rgb = apply_tonemapping(frag_color.rgb);
 #endif
 	frag_color.rgb = linear_to_srgb(frag_color.rgb);
 
@@ -2806,7 +2806,7 @@ void main() {
 	// Tonemap before writing as we are writing to an sRGB framebuffer
 	additive_light_color *= exposure;
 #ifdef APPLY_TONEMAPPING
-	additive_light_color = apply_tonemapping(additive_light_color, white);
+	additive_light_color = apply_tonemapping(additive_light_color);
 #endif
 	additive_light_color = linear_to_srgb(additive_light_color);
 

drivers/gles3/shaders/sky.glsl

@@ -265,7 +265,7 @@ void main() {
 
 	color *= exposure;
 #ifdef APPLY_TONEMAPPING
-	color = apply_tonemapping(color, white);
+	color = apply_tonemapping(color);
 #endif
 	color = linear_to_srgb(color);