WebGLSync

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The WebGLSync interface is part of the WebGL 2 API and is used to synchronize activities between the GPU and the application.

When working with WebGLSync objects, the following methods of the WebGL2RenderingContext are useful:

• WebGL2RenderingContext.fenceSync()
• WebGL2RenderingContext.deleteSync()
• WebGL2RenderingContext.isSync()
• WebGL2RenderingContext.clientWaitSync()
• WebGL2RenderingContext.waitSync()
• WebGL2RenderingContext.getSyncParameter()

Examples

Creating a WebGLSync object

in this example, gl must be a WebGL2RenderingContext. WebGLSync objects are not available in WebGL 1.

var sync = gl.fenceSync(gl.SYNC_GPU_COMMANDS_COMPLETE, 0);

Specifications

Specification	Status	Comment
WebGL 2.0 The definition of 'WebGLSync' in that specification.	Editor's Draft	Initial definition.

Browser compatibility

• Desktop
• Mobile

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Servo
Basic Support	No support1	No support	51.0	No support	No support	No support	No support

1. To use an experimental implementation of WebGL 2 in Chrome, you have to start Chrome with the runtime flag --enable-unsafe-es3-apis.

See also

• WebGLRenderingContext.finish()

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WebGLShaderPrecisionFormat

The WebGLShaderPrecisionFormat interface is part of the WebGL API and represents the information returned by calling the WebGLRenderingContext.getShaderPrecisionFormat() method.

Properties

WebGLShaderPrecisionFormat.rangeMin

The base 2 log of the absolute value of the minimum value that can be represented.

WebGLShaderPrecisionFormat.rangeMax

The base 2 log of the absolute value of the maximum value that can be represented.

WebGLShaderPrecisionFormat.precision

The number of bits of precision that can be represented. For integer formats this value is always 0.

Examples

A WebGLShaderPrecisionFormat object is returned by the WebGLRenderingContext.getShaderPrecisionFormat() method.

var canvas = document.getElementById("canvas"); 
var gl = canvas.getContext("webgl");
gl.getShaderPrecisionFormat(gl.VERTEX_SHADER, gl.MEDIUM_FLOAT);
// WebGLShaderPrecisionFormat { rangeMin: 127, rangeMax: 127, precision: 23 }

Specifications

Specification	Status	Comment
WebGL 1.0 The definition of 'WebGLShaderPrecisionFormat' in that specification.	Recommendation	Initial definition.

Browser compatibility

• Desktop
• Mobile

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Servo
Basic Support	9	12	11.0	11	12	5.1	No support
Available in workers	No support	No support	No support1	No support	No support	No support	No support

1. This feature is experimentally implemented since Firefox 44; to activate it, in about:config, set gfx.offscreencanvas.enabled to true

See also

• WebGLRenderingContext.getShaderPrecisionFormat()

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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
  var shader = gl.createShader( type );
  gl.shaderSource( shader, sourceCode );
  gl.compileShader( shader );

  if ( !gl.getShaderParameter(shader, gl.COMPILE_STATUS) ) {
    var 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.

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

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

Creating a fragment shader

var 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
var fragmentShader = createShader(gl, fragmentShaderSource, gl.FRAGMENT_SHADER)

Specifications

Specification	Status	Comment
WebGL 1.0 The definition of 'WebGLShader' in that specification.	Recommendation	Initial definition.

Browser compatibility

• Desktop
• Mobile

Feature	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Servo
Basic Support	9	12	4.0	11	12	5.1	No support
Available in workers	No support	No support	No support1	No support	No support	No support	No support

1. This feature is experimentally implemented since Firefox 44; to activate it, in about:config, set gfx.offscreencanvas.enabled to true

See also

• WebGLProgram
• WebGLRenderingContext.attachShader()
• WebGLRenderingContext.bindAttribLocation()
• 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()

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