Function createProgram

demo/js/index3.js:4772–4806

(gl, vertexScript, fragScript)

}

function createProgram(gl, vertexScript, fragScript) {
  var vertexShader = createShader(gl, vertexScript, gl.VERTEX_SHADER);
  var fragShader = createShader(gl, fragScript, gl.FRAGMENT_SHADER);

  var program = gl.createProgram();
  gl.attachShader(program, vertexShader);
  gl.attachShader(program, fragShader);

  gl.linkProgram(program);

  var linked = gl.getProgramParameter(program, gl.LINK_STATUS);
  if (!linked) {
    var lastError = gl.getProgramInfoLog(program);
    error("Error in program linking: " + lastError);
    gl.deleteProgram(program);
    return null;
  }

  var positionLocation = gl.getAttribLocation(program, "a_position");
  var texCoordLocation = gl.getAttribLocation(program, "a_texCoord");

  var texCoordBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, texCoordBuffer);
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 1.0, 0.0, 1.0, 1.0]), gl.STATIC_DRAW);
  gl.enableVertexAttribArray(texCoordLocation);
  gl.vertexAttribPointer(texCoordLocation, 2, gl.FLOAT, false, 0, 0);

  // Create a buffer for the position of the rectangle corners.
  var buffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
  gl.enableVertexAttribArray(positionLocation);
  gl.vertexAttribPointer(positionLocation, 2, gl.FLOAT, false, 0, 0);

  return program;
}

function createShader(gl, script, type) {
  var shader = gl.createShader(type);