gl-shader.ts

export function initShaderProgram(gl: WebGLRenderingContext, vsSource: string, fsSource: string): WebGLProgram | null{
  const vertexShader = loadShader(gl, gl.VERTEX_SHADER, vsSource);
  const fragmentShader = loadShader(gl, gl.FRAGMENT_SHADER, fsSource);

  const shaderProgram = gl.createProgram();

  if (shaderProgram === null || vertexShader === null  || fragmentShader === null) {
    return null;
  }

  gl.attachShader(shaderProgram, vertexShader);
  gl.attachShader(shaderProgram, fragmentShader);
  gl.linkProgram(shaderProgram);

  if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
    return null;
  }

  return shaderProgram;
}

function loadShader(gl: WebGLRenderingContext, type: number, source: string): WebGLShader | null {
  const shader: WebGLShader | null = gl.createShader(type);

  if (shader === null) {
    return shader;
  }

  gl.shaderSource(shader, source);
  gl.compileShader(shader);

  if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
    gl.deleteShader(shader);
    return null;
  }

  return shader;
}