WebGL2RenderingContext.drawElementsInstanced()

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 WebGL2RenderingContext.drawElementsInstanced() method of the WebGL 2 API renders primitives from array data like the gl.drawElements() method. In addition, it can execute multiple instances of a set of elements.

Note: When using WebGL 1, the ANGLE_instanced_arrays extension can provide this method, too.

Syntax

void gl.drawElementsInstanced(mode, count, type, offset, instanceCount);

Parameters

mode
A GLenum specifying the type primitive to render. Possible values are:
  • gl.POINTS: Draws a single dot.
  • gl.LINE_STRIP: Draws a straight line to the next vertex.
  • gl.LINE_LOOP: Draws a straight line to the next vertex, and connects the last vertex back to the first.
  • gl.LINES: Draws a line between a pair of vertices.
  • gl.TRIANGLE_STRIP
  • gl.TRIANGLE_FAN
  • gl.TRIANGLES: Draws a triangle for a group of three vertices.
count
A GLsizei specifying the number of elements to be rendered.
type
A GLenum specifying the type of the values in the element array buffer. Possible values are:
offset
A GLintptr specifying an offset in the element array buffer. Must be a valid multiple of the size of the given type.
instanceCount
A GLsizei specifying the number of instances of the set of elements to execute.

Return value

None.

Exceptions

  • If mode is not one of the accepted values, a gl.INVALID_ENUM error is thrown.
  • If offset is a valid multiple of the size of the given type, a gl.INVALID_OPERATION error is thrown.
  • If count or instanceCount are negative, a gl.INVALID_VALUE error is thrown.

Examples

gl.drawElementsInstanced(gl.POINTS, 2, gl.UNSIGNED_SHORT, 0, 4);

Specifications

Specification Status Comment
WebGL 2.0
The definition of 'drawElementsInstanced' in that specification.
Editor's Draft Initial definition for WebGL.
OpenGL ES 3.0
The definition of 'glDrawElementsInstanced' in that specification.
Standard Man page of the (similar) OpenGL API.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support [2] Nightly build [1] No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support No support No support No support No support

[1] WebGL 2 is enabled by default in Firefox Nightly. To enable it in a release version of Firefox, set the preference webgl.enable-prototype-webgl2 to true in about:config.

[2] 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

License

© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/webgl2renderingcontext/drawelementsinstanced