ShadowNode: Add support for `renderer.highPrecision` (#33246)

src/nodes/lighting/ShadowNode.js

@@ -1,5 +1,5 @@
 import ShadowBaseNode, { shadowPositionWorld } from './ShadowBaseNode.js';
-import { float, vec2, vec3, int, Fn } from '../tsl/TSLBase.js';
+import { float, vec2, vec3, vec4, int, Fn } from '../tsl/TSLBase.js';
 import { reference } from '../accessors/ReferenceNode.js';
 import { texture, textureLoad } from '../accessors/TextureNode.js';
 import { cubeTexture } from '../accessors/CubeTextureNode.js';
@@ -21,6 +21,8 @@ import { getShadowMaterial, disposeShadowMaterial, BasicShadowFilter, PCFShadowF
 import ChainMap from '../../renderers/common/ChainMap.js';
 import { textureSize } from '../accessors/TextureSizeNode.js';
 import { uv } from '../accessors/UV.js';
+import { positionLocal } from '../accessors/Position.js';
+import { uniform } from '../core/UniformNode.js';
 
 //
 
@@ -506,7 +508,27 @@ class ShadowNode extends ShadowBaseNode {
 		const shadowIntensity = reference( 'intensity', 'float', shadow ).setGroup( renderGroup );
 		const normalBias = reference( 'normalBias', 'float', shadow ).setGroup( renderGroup );
 
-		const shadowPosition = lightShadowMatrix( light ).mul( shadowPositionWorld.add( normalWorld.mul( normalBias ) ) );
+		const shadowMatrix = lightShadowMatrix( light );
+		const shadowNormalBias = normalWorld.mul( normalBias );
+
+		let shadowPosition;
+
+		if ( ! renderer.highPrecision || builder.material.receivedShadowPositionNode || builder.context.shadowPositionWorld ) {
+
+			shadowPosition = shadowMatrix.mul( shadowPositionWorld.add( shadowNormalBias ) );
+
+		} else {
+
+			const highpShadowModelMatrix = uniform( 'mat4' ).onObjectUpdate( ( { object }, self ) => {
+
+				return self.value.multiplyMatrices( shadowMatrix.value, object.matrixWorld );
+
+			} );
+
+			shadowPosition = highpShadowModelMatrix.mul( positionLocal ).add( shadowMatrix.mul( vec4( shadowNormalBias, 0 ) ) );
+
+		}
+
 		const shadowCoord = this.setupShadowCoord( builder, shadowPosition );
 
 		//