153 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
		
		
			
		
	
	
			153 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
|  | import { Vector3, Matrix4 } from 'three'; | ||
|  | 
 | ||
|  | const inverseProjectionMatrix = new Matrix4(); | ||
|  | 
 | ||
|  | class CSMFrustum { | ||
|  | 
 | ||
|  | 	constructor( data ) { | ||
|  | 
 | ||
|  | 		data = data || {}; | ||
|  | 
 | ||
|  | 		this.vertices = { | ||
|  | 			near: [ | ||
|  | 				new Vector3(), | ||
|  | 				new Vector3(), | ||
|  | 				new Vector3(), | ||
|  | 				new Vector3() | ||
|  | 			], | ||
|  | 			far: [ | ||
|  | 				new Vector3(), | ||
|  | 				new Vector3(), | ||
|  | 				new Vector3(), | ||
|  | 				new Vector3() | ||
|  | 			] | ||
|  | 		}; | ||
|  | 
 | ||
|  | 		if ( data.projectionMatrix !== undefined ) { | ||
|  | 
 | ||
|  | 			this.setFromProjectionMatrix( data.projectionMatrix, data.maxFar || 10000 ); | ||
|  | 
 | ||
|  | 		} | ||
|  | 
 | ||
|  | 	} | ||
|  | 
 | ||
|  | 	setFromProjectionMatrix( projectionMatrix, maxFar ) { | ||
|  | 
 | ||
|  | 		const isOrthographic = projectionMatrix.elements[ 2 * 4 + 3 ] === 0; | ||
|  | 
 | ||
|  | 		inverseProjectionMatrix.copy( projectionMatrix ).invert(); | ||
|  | 
 | ||
|  | 		// 3 --- 0  vertices.near/far order
 | ||
|  | 		// |     |
 | ||
|  | 		// 2 --- 1
 | ||
|  | 		// clip space spans from [-1, 1]
 | ||
|  | 
 | ||
|  | 		this.vertices.near[ 0 ].set( 1, 1, - 1 ); | ||
|  | 		this.vertices.near[ 1 ].set( 1, - 1, - 1 ); | ||
|  | 		this.vertices.near[ 2 ].set( - 1, - 1, - 1 ); | ||
|  | 		this.vertices.near[ 3 ].set( - 1, 1, - 1 ); | ||
|  | 		this.vertices.near.forEach( function ( v ) { | ||
|  | 
 | ||
|  | 			v.applyMatrix4( inverseProjectionMatrix ); | ||
|  | 
 | ||
|  | 		} ); | ||
|  | 
 | ||
|  | 		this.vertices.far[ 0 ].set( 1, 1, 1 ); | ||
|  | 		this.vertices.far[ 1 ].set( 1, - 1, 1 ); | ||
|  | 		this.vertices.far[ 2 ].set( - 1, - 1, 1 ); | ||
|  | 		this.vertices.far[ 3 ].set( - 1, 1, 1 ); | ||
|  | 		this.vertices.far.forEach( function ( v ) { | ||
|  | 
 | ||
|  | 			v.applyMatrix4( inverseProjectionMatrix ); | ||
|  | 
 | ||
|  | 			const absZ = Math.abs( v.z ); | ||
|  | 			if ( isOrthographic ) { | ||
|  | 
 | ||
|  | 				v.z *= Math.min( maxFar / absZ, 1.0 ); | ||
|  | 
 | ||
|  | 			} else { | ||
|  | 
 | ||
|  | 				v.multiplyScalar( Math.min( maxFar / absZ, 1.0 ) ); | ||
|  | 
 | ||
|  | 			} | ||
|  | 
 | ||
|  | 		} ); | ||
|  | 
 | ||
|  | 		return this.vertices; | ||
|  | 
 | ||
|  | 	} | ||
|  | 
 | ||
|  | 	split( breaks, target ) { | ||
|  | 
 | ||
|  | 		while ( breaks.length > target.length ) { | ||
|  | 
 | ||
|  | 			target.push( new CSMFrustum() ); | ||
|  | 
 | ||
|  | 		} | ||
|  | 
 | ||
|  | 		target.length = breaks.length; | ||
|  | 
 | ||
|  | 		for ( let i = 0; i < breaks.length; i ++ ) { | ||
|  | 
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|  | 			const cascade = target[ i ]; | ||
|  | 
 | ||
|  | 			if ( i === 0 ) { | ||
|  | 
 | ||
|  | 				for ( let j = 0; j < 4; j ++ ) { | ||
|  | 
 | ||
|  | 					cascade.vertices.near[ j ].copy( this.vertices.near[ j ] ); | ||
|  | 
 | ||
|  | 				} | ||
|  | 
 | ||
|  | 			} else { | ||
|  | 
 | ||
|  | 				for ( let j = 0; j < 4; j ++ ) { | ||
|  | 
 | ||
|  | 					cascade.vertices.near[ j ].lerpVectors( this.vertices.near[ j ], this.vertices.far[ j ], breaks[ i - 1 ] ); | ||
|  | 
 | ||
|  | 				} | ||
|  | 
 | ||
|  | 			} | ||
|  | 
 | ||
|  | 			if ( i === breaks.length - 1 ) { | ||
|  | 
 | ||
|  | 				for ( let j = 0; j < 4; j ++ ) { | ||
|  | 
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|  | 					cascade.vertices.far[ j ].copy( this.vertices.far[ j ] ); | ||
|  | 
 | ||
|  | 				} | ||
|  | 
 | ||
|  | 			} else { | ||
|  | 
 | ||
|  | 				for ( let j = 0; j < 4; j ++ ) { | ||
|  | 
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|  | 					cascade.vertices.far[ j ].lerpVectors( this.vertices.near[ j ], this.vertices.far[ j ], breaks[ i ] ); | ||
|  | 
 | ||
|  | 				} | ||
|  | 
 | ||
|  | 			} | ||
|  | 
 | ||
|  | 		} | ||
|  | 
 | ||
|  | 	} | ||
|  | 
 | ||
|  | 	toSpace( cameraMatrix, target ) { | ||
|  | 
 | ||
|  | 		for ( let i = 0; i < 4; i ++ ) { | ||
|  | 
 | ||
|  | 			target.vertices.near[ i ] | ||
|  | 				.copy( this.vertices.near[ i ] ) | ||
|  | 				.applyMatrix4( cameraMatrix ); | ||
|  | 
 | ||
|  | 			target.vertices.far[ i ] | ||
|  | 				.copy( this.vertices.far[ i ] ) | ||
|  | 				.applyMatrix4( cameraMatrix ); | ||
|  | 
 | ||
|  | 		} | ||
|  | 
 | ||
|  | 	} | ||
|  | 
 | ||
|  | } | ||
|  | 
 | ||
|  | export { CSMFrustum }; |