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