shaku/src/gfx/mesh.js

A simple and effective JavaScript game development framework that knows its place!

/**
 * Define a mesh object.
 * 
 * |-- copyright and license --|
 * @module     Shaku
 * @file       shaku\src\gfx\mesh.js
 * @author     Ronen Ness (ronenness@gmail.com | http://ronenness.com)
 * @copyright  (c) 2021 Ronen Ness
 * @license    MIT
 * |-- end copyright and license --|
 * 
 */

 'use strict';

const { Color } = require("../utils");

 /**
  * Class to hold a mesh.
  */
 class Mesh
 {
    /**
     * Create the mesh object.
     * @param {WebGLBuffer} positions vertices positions buffer. 
     * @param {WebGLBuffer} textureCoords vertices texture coords buffer.
     * @param {WebGLBuffer} colorss vertices colors buffer.
     * @param {WebGLBuffer} indices indices buffer.
     * @param {Number} indicesCount how many indices we have.
     */
    constructor(positions, textureCoords, colorsBuffer, indices, indicesCount)
    {
        this.positions = positions;
        this.textureCoords = textureCoords;
        this.colors = colorsBuffer;
        this.indices = indices;
        this.indicesCount = indicesCount;
        this.__color = new Color(-1, -1, -1, -1);
        Object.freeze(this);
    }

    /**
     * Override the colors buffer, if possible.
     * @param {WebGl} gl WebGL context.
     * @param {Color} color Color to set.
     */
    overrideColors(gl, color)
    {
        if (color.equals(this.__color)) { return; }
        this.__color.copy(color);

        gl.bindBuffer(gl.ARRAY_BUFFER, this.colors);
        const colors = [];
        for (let i = 0; i < this.indicesCount; ++i) {
            colors.push(color.r);
            colors.push(color.g);
            colors.push(color.b);
            colors.push(color.a);
        }
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(colors), gl.DYNAMIC_DRAW);
    }
 }
 
 // export the mesh class.
 module.exports = Mesh;