WebGLProgram

The WebGLProgram is part of the WebGL API and is a combination of two compiled WebGLShaders consisting of a vertex shader and a fragment shader (both written in GLSL).

To create a WebGLProgram, call the GL context's createProgram() function. After attaching the shader programs using attachShader(), you link them into a usable program. This is shown in the code below.

var program = gl.createProgram();

// Attach pre-existing shaders
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);

gl.linkProgram(program);

if ( !gl.getProgramParameter( program, gl.LINK_STATUS) ) {
  var info = gl.getProgramInfoLog(program);
  throw 'Could not compile WebGL program. \n\n' + info;
}

See WebGLShader for information on creating the vertexShader and fragmentShader in the above example.

The steps to actually do some work with the program involve telling the GPU to use the program, bind the appropriate data and configuration options, and finally draw something to the screen.

// Use the program
gl.useProgram(program);

// Bind existing attribute data
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.enableVertexAttribArray(attributeLocation);
gl.vertexAttribPointer(attributeLocation, 3, gl.FLOAT, false, 0, 0);

// Draw a single triangle
gl.drawArrays(gl.TRIANGLES, 0, 3);

If there is an error linking the program or you wish to delete an existing program, then it is as simple as running WebGLRenderingContext.deleteProgram(). This frees the memory of the linked program.

gl.deleteProgram(program);

• WebGLShader
• WebGLRenderingContext.attachShader()
• WebGLRenderingContext.compileShader()
• WebGLRenderingContext.createProgram()
• WebGLRenderingContext.createShader()
• WebGLRenderingContext.deleteProgram()
• WebGLRenderingContext.deleteShader()
• WebGLRenderingContext.detachShader()
• WebGLRenderingContext.getAttachedShaders()
• WebGLRenderingContext.getProgramParameter()
• WebGLRenderingContext.getProgramInfoLog()
• WebGLRenderingContext.getShaderParameter()
• WebGLRenderingContext.getShaderPrecisionFormat()
• WebGLRenderingContext.getShaderInfoLog()
• WebGLRenderingContext.getShaderSource()
• WebGLRenderingContext.isProgram()
• WebGLRenderingContext.isShader()
• WebGLRenderingContext.linkProgram()
• WebGLRenderingContext.shaderSource()
• WebGLRenderingContext.useProgram()
• WebGLRenderingContext.validateProgram()