Merge pull request #18735 from gkjohnson/csm-breaks-cache-arrays

CSM: Remove array allocation in getBreaks, getExtendedBreaks

examples/jsm/csm/CSM.js

@@ -24,6 +24,8 @@ const _lightSpaceFrustum = new Frustum();
 const _frustum = new Frustum();
 const _center = new Vector3();
 const _bbox = new FrustumBoundingBox();
+const _uniformArray = [];
+const _logArray = [];
 
 export default class CSM {
 
@@ -46,6 +48,7 @@ export default class CSM {
 		this.customSplitsCallback = data.customSplitsCallback;
 		this.mainFrustum = new Frustum();
 		this.frustums = [];
+		this.breaks = [];
 
 		this.lights = [];
 		this.materials = [];
@@ -92,70 +95,64 @@ export default class CSM {
 
 		const camera = this.camera;
 		const far = Math.min(camera.far, this.maxFar);
-		this.breaks = [];
+		this.breaks.length = 0;
 
 		switch ( this.mode ) {
 
 			case 'uniform':
-				this.breaks = uniformSplit( this.cascades, camera.near, far );
+				uniformSplit( this.cascades, camera.near, far, this.breaks );
 				break;
 			case 'logarithmic':
-				this.breaks = logarithmicSplit( this.cascades, camera.near, far );
+				logarithmicSplit( this.cascades, camera.near, far, this.breaks );
 				break;
 			case 'practical':
-				this.breaks = practicalSplit( this.cascades, camera.near, far, 0.5 );
+				practicalSplit( this.cascades, camera.near, far, 0.5, this.breaks );
 				break;
 			case 'custom':
 				if ( this.customSplitsCallback === undefined ) console.error( 'CSM: Custom split scheme callback not defined.' );
-				this.breaks = this.customSplitsCallback( this.cascades, camera.near, far );
+				this.customSplitsCallback( this.cascades, camera.near, far, this.breaks );
 				break;
 
 		}
 
-		function uniformSplit( amount, near, far ) {
-
-			const r = [];
+		function uniformSplit( amount, near, far, target ) {
 
 			for ( let i = 1; i < amount; i ++ ) {
 
-				r.push( ( near + ( far - near ) * i / amount ) / far );
+				target.push( ( near + ( far - near ) * i / amount ) / far );
 
 			}
 
-			r.push( 1 );
-			return r;
+			target.push( 1 );
 
 		}
 
-		function logarithmicSplit( amount, near, far ) {
-
-			const r = [];
+		function logarithmicSplit( amount, near, far, target ) {
 
 			for ( let i = 1; i < amount; i ++ ) {
 
-				r.push( ( near * ( far / near ) ** ( i / amount ) ) / far );
+				target.push( ( near * ( far / near ) ** ( i / amount ) ) / far );
 
 			}
 
-			r.push( 1 );
-			return r;
+			target.push( 1 );
 
 		}
 
-		function practicalSplit( amount, near, far, lambda ) {
+		function practicalSplit( amount, near, far, lambda, target ) {
 
-			const log = logarithmicSplit( amount, near, far );
-			const uni = uniformSplit( amount, near, far );
-			const r = [];
+			_uniformArray.length = 0;
+			_logArray.length = 0;
+			const log = logarithmicSplit( amount, near, far, _logArray );
+			const uni = uniformSplit( amount, near, far, _uniformArray );
 
 			for ( let i = 1; i < amount; i ++ ) {
 
-				r.push( MathUtils.lerp( uni[ i - 1 ], log[ i - 1 ], lambda ) );
+				target.push( MathUtils.lerp( _uniformArray[ i - 1 ], _logArray[ i - 1 ], lambda ) );
 
 			}
 
-			r.push( 1 );
-			return r;
+			target.push( 1 );
 
 		}
 
@@ -213,14 +210,7 @@ export default class CSM {
 		material.defines.CSM_CASCADES = this.cascades;
 
 		const breaksVec2 = [];
-
-		for ( let i = 0; i < this.cascades; i ++ ) {
-
-			let amount = this.breaks[ i ];
-			let prev = this.breaks[ i - 1 ] || 0;
-			breaksVec2.push( new Vector2( prev, amount ) );
-
-		}
+		this.getExtendedBreaks( breaksVec2 );
 
 		const self = this;
 		const far = Math.min(this.camera.far, this.maxFar);
@@ -243,28 +233,33 @@ export default class CSM {
 
 		for ( let i = 0; i < this.materials.length; i ++ ) {
 
-			this.materials[ i ].uniforms.CSM_cascades.value = this.getExtendedBreaks();
-			this.materials[ i ].uniforms.cameraNear.value = this.camera.near;
-			this.materials[ i ].uniforms.shadowFar.value = far;
+			const uniforms = this.materials[ i ].uniforms;
+			this.getExtendedBreaks( uniforms.CSM_cascades.value );
+			uniforms.cameraNear.value = this.camera.near;
+			uniforms.shadowFar.value = far;
 
 		}
 
 	}
 
-	getExtendedBreaks() {
+	getExtendedBreaks( target ) {
+
+		while ( target.length < this.breaks.length ) {
 
-		let breaksVec2 = [];
+			target.push( new Vector2() );
+
+		}
+		target.length = this.breaks.length;
 
 		for ( let i = 0; i < this.cascades; i ++ ) {
 
 			let amount = this.breaks[ i ];
 			let prev = this.breaks[ i - 1 ] || 0;
-			breaksVec2.push( new Vector2( prev, amount ) );
+			target[ i ].x = prev;
+			target[ i ].y = amount;
 
 		}
 
-		return breaksVec2;
-
 	}
 
 	updateFrustums() {