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WebGLShader

The WebGLShader is part of the WebGL API and can either be a vertex or a fragment shader. A WebGLProgram requires both types of shaders.

Description

To create a WebGLShader use WebGLRenderingContext.createShader, then hook up the GLSL source code using WebGLRenderingContext.shaderSource(), and finally invoke WebGLRenderingContext.compileShader() to finish and compile the shader. At this point the WebGLShader is still not in a usable form and must still be attached to a WebGLProgram.

function createShader(gl, sourceCode, type) {
  // Compiles either a shader of type gl.VERTEX_SHADER or gl.FRAGMENT_SHADER
  const shader = gl.createShader(type);
  gl.shaderSource(shader, sourceCode);
  gl.compileShader(shader);

  if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
    const info = gl.getShaderInfoLog(shader);
    throw `Could not compile WebGL program. \n\n${info}`;
  }
  return shader;
}

See WebGLProgram for information on attaching the shaders.

Examples

Creating a vertex shader

Note that there are many other strategies for writing and accessing shader source code strings. These example are for illustration purposes only.

const vertexShaderSource =
  "attribute vec4 position;\n" +
  "void main() {\n" +
  "  gl_Position = position;\n" +
  "}\n";

//Use the createShader function from the example above
const vertexShader = createShader(gl, vertexShaderSource, gl.VERTEX_SHADER);

Creating a fragment shader

const fragmentShaderSource =
  "void main() {\n" + "  gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);\n" + "}\n";

//Use the createShader function from the example above
const fragmentShader = createShader(
  gl,
  fragmentShaderSource,
  gl.FRAGMENT_SHADER,
);

Specifications

Specification
WebGL Specification # 5.8

Browser compatibility