git.r.bdr.sh - rbdr/lissajous/blob - lib/webgl_utils.js

   1 /**
   2   * Initializes the WebGL Shader program
   3   */
   4 export function initializeShaderProgram(gl, vertexShaderSource, fragmentShaderSource) {
   5
   6   const vertexShader = loadShader(gl, gl.VERTEX_SHADER, vertexShaderSource);
   7   const fragmentShader = loadShader(gl, gl.FRAGMENT_SHADER, fragmentShaderSource);
   8
   9   const shaderProgram = gl.createProgram();
  10   gl.attachShader(shaderProgram, vertexShader);
  11   gl.attachShader(shaderProgram, fragmentShader);
  12
  13   gl.linkProgram(shaderProgram);
  14
  15   if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
  16     console.error(`Unable to initialize shader program: ${gl.getProgramInfoLog(shaderProgram)}`);
  17     return null;
  18   }
  19
  20   return shaderProgram;
  21 }
  22
  23 /**
  24   * Initializes the buffers
  25   */
  26 export function initializeBuffers(gl) {
  27
  28   const positionBuffer = gl.createBuffer();
  29
  30   gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
  31
  32   return {
  33     position: positionBuffer
  34   };
  35 }
  36
  37
  38 /**
  39   * Loads and compiles a shader
  40   */
  41 function loadShader(gl, type, source) {
  42
  43   const shader = gl.createShader(type);
  44   gl.shaderSource(shader, source);
  45   gl.compileShader(shader);
  46
  47   if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
  48     console.error(`Unable to compile shader: ${gl.getShaderInfoLog(shader)}`);
  49     gl.deleteShader(shader);
  50     return null;
  51   }
  52
  53   return shader;
  54 }