Add CSMHelper

examples/jsm/csm/CSMHelper.js

@@ -0,0 +1,110 @@
+import { Group, Mesh, LineSegments, BufferGeometry, LineBasicMaterial, Box3Helper, Box3, PlaneBufferGeometry, MeshBasicMaterial } from '../../../build/three.module.js';
+
+class CSMHelper extends Group {
+
+	constructor( csm ) {
+
+		super();
+		this.csm = csm;
+
+		const indices = new Uint16Array( [ 0, 1, 1, 2, 2, 3, 3, 0, 4, 5, 5, 6, 6, 7, 7, 4, 0, 4, 1, 5, 2, 6, 3, 7 ] );
+		const positions = new Float32Array( 24 );
+		const frustumGeometry = new BufferGeometry();
+		frustumGeometry.setIndex( new BufferAttribute( indices, 1 ) );
+		frustumGeometry.setAttribute( 'position', new BufferAttribute( positions, 3, false ) );
+		this.add( frustumGeometry );
+
+		this.frustumLines = new LineSegments( frustumGeometry, new LineBasicMaterial() );
+		this.cascadeLines = [];
+		this.cascadePlanes = [];
+		this.shadowLines = [];
+
+	}
+
+	update() {
+
+		const csm = this.csm;
+		const cascades = csm.cascades;
+		const mainFrustum = csm.mainFrustum;
+		const mainFrustumPositions = mainFrustum.geometry.positions;
+		const frustums = csm.frustums;
+		const lights = csm.lights;
+
+		const frustumLines = this.frustumLines;
+		const cascadeLines = this.cascadeLines;
+		const cascadePlanes = this.cascadePlanes;
+		const shadowLines = this.shadowLines;
+
+		while( cascadeLines.length > cascades ) {
+
+			this.remove( cascadeLines.pop() );
+			this.remove( cascadePlanes.pop() );
+			this.remove( shadowLines.pop() );
+
+		}
+
+		while( cascadeLines.length < cascades ) {
+
+			const cascadeLine = new Box3Helper( new Box3(), 0xffffff );
+			const cascadePlane = new Mesh( new PlaneBufferGeometry(), new MeshBasicMaterial( { transparent: true, opacity: 0.1 } ) );
+			const shadowLineGroup = new Group();
+			const shadowLine = new Box3Helper( new Box3(), 0xffff00 );
+			shadowLineGroup.add( shadowLine );
+
+			this.add( cascadeLine );
+			this.add( cascadePlane );
+			this.add( shadowLine );
+
+			cascadeLines.push( cascadeLine );
+			cascadePlanes.push( cascadePlane );
+			shadowLines.push( shadowLineGroup );
+
+		}
+
+		for ( let i = 0; i < cascades; i ++ ) {
+
+			const frustum = frustums[ i ];
+			const light = lights[ i ];
+			const shadowCam = light.shadow.camera;
+			const farVerts = frustum.vertices.far;
+
+			const cascadeLine = cascadeLines[ i ];
+			const cascadePlane = cascadePlanes[ i ];
+			const shadowLineGroup = shadowLines[ i ];
+			const shadowLine = shadowLineGroup.children[ 0 ];
+
+			cascadeLine.box.min.copy( farVerts[ 2 ] );
+			cascadeLine.box.max.copy( farVerts[ 0 ] );
+
+			cascadePlane.position.addVectors( farVerts[ 0 ], farVerts[ 2 ] );
+			cascadePlane.position.multiplyScalar( 0.5 );
+			cascadePlane.scale.subVectors( farVerts[ 0 ], farVerts[ 2 ] );
+
+			this.remove( shadowLineGroup );
+			shadowCam.matrixWorld.decompose( shadowLineGroup.position, shadowLineGroup.quaternion, shadowLineGroup.scale );
+			this.attach( shadowLineGroup );
+
+			shadowLine.box.min.set( shadowCam.bottom, shadowCam.left, shadowCam.near );
+			shadowLine.box.max.set( shadowCam.top, shadowCam.right, shadowCam.far );
+
+			cascadeLine.update();
+			shadowLine.update();
+
+		}
+
+		mainFrustumPositions.setXYZ( 0, farVerts[ 0 ] );
+		mainFrustumPositions.setXYZ( 1, farVerts[ 3 ] );
+		mainFrustumPositions.setXYZ( 2, farVerts[ 2 ] );
+		mainFrustumPositions.setXYZ( 3, farVerts[ 1 ] );
+
+		mainFrustumPositions.setXYZ( 4, nearVerts[ 0 ] );
+		mainFrustumPositions.setXYZ( 5, nearVerts[ 3 ] );
+		mainFrustumPositions.setXYZ( 6, nearVerts[ 2 ] );
+		mainFrustumPositions.setXYZ( 7, nearVerts[ 1 ] );
+		mainFrustumPositions.needsUpdate = true;
+
+	}
+
+}
+
+export { CSMHelper };