📄 `ShadowMesh.js`¶

📊 Analysis Summary¶

Metric	Count
🔧 Functions	1
🧱 Classes	1
📦 Imports	5
📊 Variables & Constants	4

📚 Table of Contents¶

Imports
Variables & Constants
Functions
Classes

🛠️ File Location:¶

📂 examples/jsm/objects/ShadowMesh.js

📦 Imports¶

Name	Source
`Matrix4`	`three`
`Mesh`	`three`
`MeshBasicMaterial`	`three`
`EqualStencilFunc`	`three`
`IncrementStencilOp`	`three`

Variables & Constants¶

Name	Type	Kind	Value	Exported
`_shadowMatrix`	`any`	let/var	`new Matrix4()`	✗
`shadowMaterial`	`any`	let/var	`new MeshBasicMaterial( { color: 0x000000, transparent: true, opacity: 0.6, de...`	✗
`dot`	`number`	let/var	`plane.normal.x * lightPosition4D.x + plane.normal.y * lightPosition4D.y + pla...`	✗
`sme`	`any`	let/var	`_shadowMatrix.elements`	✗

Functions¶

`ShadowMesh.update(plane: Plane, lightPosition4D: Vector4): void`¶

JSDoc:

/**
     * Updates the shadow mesh so it follows its shadow-casting reference mesh.
     *
     * @param {Plane} plane - The plane onto the shadow mesh is projected.
     * @param {Vector4} lightPosition4D - The light position.
     */

Parameters:

plane Plane
lightPosition4D Vector4

Returns: void

Calls:

this.matrix.multiplyMatrices

Internal Comments:

// based on https://www.opengl.org/archives/resources/features/StencilTalk/tsld021.htm (x2)

Code

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 );

    }

Classes¶

`ShadowMesh`¶

Class Code

class ShadowMesh extends Mesh {

    /**
     * Constructs a new shadow mesh.
     *
     * @param {Mesh} mesh - The shadow-casting reference 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 flag can be used for type testing.
         *
         * @type {boolean}
         * @readonly
         * @default true
         */
        this.isShadowMesh = true;

        /**
         * Represent the world matrix of the reference mesh.
         *
         * @type {Matrix4}
         */
        this.meshMatrix = mesh.matrixWorld;

        /**
         * Overwritten to disable view-frustum culling by default.
         *
         * @type {boolean}
         * @default false
         */
        this.frustumCulled = false;

        /**
         * Overwritten to disable automatic matrix update. The local
         * matrix is computed manually in {@link ShadowMesh#update}.
         *
         * @type {boolean}
         * @default false
         */
        this.matrixAutoUpdate = false;

    }

    /**
     * Updates the shadow mesh so it follows its shadow-casting reference mesh.
     *
     * @param {Plane} plane - The plane onto the shadow mesh is projected.
     * @param {Vector4} lightPosition4D - The light position.
     */
    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 );

    }

}

Methods¶

`update(plane: Plane, lightPosition4D: Vector4): void`¶

Code

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 );

    }

📄 ShadowMesh.js¶

📊 Analysis Summary¶

📚 Table of Contents¶

🛠️ File Location:¶

📦 Imports¶

Variables & Constants¶

Functions¶

ShadowMesh.update(plane: Plane, lightPosition4D: Vector4): void¶

Classes¶

ShadowMesh¶

Methods¶

update(plane: Plane, lightPosition4D: Vector4): void¶

📄 `ShadowMesh.js`¶

`ShadowMesh.update(plane: Plane, lightPosition4D: Vector4): void`¶

`ShadowMesh`¶

`update(plane: Plane, lightPosition4D: Vector4): void`¶