You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
81 lines
2.0 KiB
81 lines
2.0 KiB
6 months ago
|
import {
|
||
|
|
Matrix4,
|
||
|
|
Mesh,
|
||
|
|
MeshBasicMaterial,
|
||
|
|
EqualStencilFunc,
|
||
|
|
IncrementStencilOp
|
||
|
|
} from 'three';
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A shadow Mesh that follows a shadow-casting Mesh in the scene, but is confined to a single plane.
|
||
|
|
*/
|
||
|
|
|
||
|
|
const _shadowMatrix = new Matrix4();
|
||
|
|
|
||
|
|
class ShadowMesh extends Mesh {
|
||
|
|
|
||
|
|
constructor( mesh ) {
|
||
|
|
|
||
|
|
const shadowMaterial = new MeshBasicMaterial( {
|
||
|
|
|
||
|
|
color: 0x000000,
|
||
|
|
transparent: true,
|
||
|
|
opacity: 0.6,
|
||
|
|
depthWrite: false,
|
||
|
|
stencilWrite: true,
|
||
|
|
stencilFunc: EqualStencilFunc,
|
||
|
|
stencilRef: 0,
|
||
|
|
stencilZPass: IncrementStencilOp
|
||
|
|
|
||
|
|
} );
|
||
|
|
|
||
|
|
super( mesh.geometry, shadowMaterial );
|
||
|
|
|
||
|
|
this.isShadowMesh = true;
|
||
|
|
|
||
|
|
this.meshMatrix = mesh.matrixWorld;
|
||
|
|
|
||
|
|
this.frustumCulled = false;
|
||
|
|
this.matrixAutoUpdate = false;
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
update( plane, lightPosition4D ) {
|
||
|
|
|
||
|
|
// based on https://www.opengl.org/archives/resources/features/StencilTalk/tsld021.htm
|
||
|
|
|
||
|
|
const dot = plane.normal.x * lightPosition4D.x +
|
||
|
|
plane.normal.y * lightPosition4D.y +
|
||
|
|
plane.normal.z * lightPosition4D.z +
|
||
|
|
- plane.constant * lightPosition4D.w;
|
||
|
|
|
||
|
|
const 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 };
|