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/**
* @author erichlof / http://github.com/erichlof
*
* A shadow Mesh that follows a shadow-casting Mesh in the scene, but is confined to a single plane.
*/
import {
Matrix4,
Mesh,
MeshBasicMaterial
} from "../../../build/three.module.js";
var ShadowMesh = function ( mesh ) {
var shadowMaterial = new MeshBasicMaterial( {
color: 0x000000,
transparent: true,
opacity: 0.6,
depthWrite: false
} );
Mesh.call( this, mesh.geometry, shadowMaterial );
this.meshMatrix = mesh.matrixWorld;
this.frustumCulled = false;
this.matrixAutoUpdate = false;
};
ShadowMesh.prototype = Object.create( Mesh.prototype );
ShadowMesh.prototype.constructor = ShadowMesh;
ShadowMesh.prototype.update = function () {
var shadowMatrix = new Matrix4();
return function ( plane, lightPosition4D ) {
// based on https://www.opengl.org/archives/resources/features/StencilTalk/tsld021.htm
var dot = plane.normal.x * lightPosition4D.x +
plane.normal.y * lightPosition4D.y +
plane.normal.z * lightPosition4D.z +
- plane.constant * lightPosition4D.w;
var sme = shadowMatrix.elements;
sme[ 0 ] = dot - lightPosition4D.x * plane.normal.x;
sme[ 4 ] = - lightPosition4D.x * plane.normal.y;
sme[ 8 ] = - lightPosition4D.x * plane.normal.z;
sme[ 12 ] = - lightPosition4D.x * - plane.constant;
sme[ 1 ] = - lightPosition4D.y * plane.normal.x;
sme[ 5 ] = dot - lightPosition4D.y * plane.normal.y;
sme[ 9 ] = - lightPosition4D.y * plane.normal.z;
sme[ 13 ] = - lightPosition4D.y * - plane.constant;
sme[ 2 ] = - lightPosition4D.z * plane.normal.x;
sme[ 6 ] = - lightPosition4D.z * plane.normal.y;
sme[ 10 ] = dot - lightPosition4D.z * plane.normal.z;
sme[ 14 ] = - lightPosition4D.z * - plane.constant;
sme[ 3 ] = - lightPosition4D.w * plane.normal.x;
sme[ 7 ] = - lightPosition4D.w * plane.normal.y;
sme[ 11 ] = - lightPosition4D.w * plane.normal.z;
sme[ 15 ] = dot - lightPosition4D.w * - plane.constant;
this.matrix.multiplyMatrices( shadowMatrix, this.meshMatrix );
};
}();
export { ShadowMesh };
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