WebGLRenderer: Consider .outputEncoding for background, clear color, and fog (#23937)

* Respect renderer.outputEncoding for background and clear color

- Applies only when ColorManagement.legacyMode = false

* Remove unused import

* Fog: Update color management under legacyMode=false to match background and clear color.

src/renderers/shaders/UniformsUtils.js

@@ -1,3 +1,5 @@
+import { sRGBEncoding, LinearSRGBColorSpace, SRGBColorSpace } from '../../constants.js';
+
 /**
  * Uniform Utilities
  */
@@ -73,6 +75,19 @@ export function cloneUniformsGroups( src ) {
 
 }
 
+export function getUnlitUniformColorSpace( renderer ) {
+
+	if ( renderer.getRenderTarget() === null ) {
+
+		// https://github.com/mrdoob/three.js/pull/23937#issuecomment-1111067398
+		return renderer.outputEncoding === sRGBEncoding ? SRGBColorSpace : LinearSRGBColorSpace;
+
+	}
+
+	return LinearSRGBColorSpace;
+
+}
+
 // Legacy
 
 const UniformsUtils = { clone: cloneUniforms, merge: mergeUniforms };

src/renderers/webgl/WebGLBackground.js

@@ -5,7 +5,9 @@ import { ShaderMaterial } from '../../materials/ShaderMaterial.js';
 import { Color } from '../../math/Color.js';
 import { Mesh } from '../../objects/Mesh.js';
 import { ShaderLib } from '../shaders/ShaderLib.js';
-import { cloneUniforms } from '../shaders/UniformsUtils.js';
+import { cloneUniforms, getUnlitUniformColorSpace } from '../shaders/UniformsUtils.js';
+
+const _rgb = { r: 0, b: 0, g: 0 };
 
 function WebGLBackground( renderer, cubemaps, cubeuvmaps, state, objects, alpha, premultipliedAlpha ) {
 
@@ -193,7 +195,9 @@ function WebGLBackground( renderer, cubemaps, cubeuvmaps, state, objects, alpha,
 
 	function setClear( color, alpha ) {
 
-		state.buffers.color.setClear( color.r, color.g, color.b, alpha, premultipliedAlpha );
+		color.getRGB( _rgb, getUnlitUniformColorSpace( renderer ) );
+
+		state.buffers.color.setClear( _rgb.r, _rgb.g, _rgb.b, alpha, premultipliedAlpha );
 
 	}
 

src/renderers/webgl/WebGLMaterials.js

@@ -1,10 +1,11 @@
 import { BackSide } from '../../constants.js';
+import { getUnlitUniformColorSpace } from '../shaders/UniformsUtils.js';
 
 function WebGLMaterials( renderer, properties ) {
 
 	function refreshFogUniforms( uniforms, fog ) {
 
-		uniforms.fogColor.value.copy( fog.color );
+		fog.color.getRGB( uniforms.fogColor.value, getUnlitUniformColorSpace( renderer ) );
 
 		if ( fog.isFog ) {