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 <var>gl</var>.drawElementsInstanced(<var>mode</var>, <var>count</var>, <var>type</var>, <var>offset</var>, <var>instanceCount</var>);
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:gl.UNSIGNED_BYTE
gl.UNSIGNED_SHORT
- When using the
OES_element_index_uint
extension:gl.UNSIGNED_INT
- offset
- A
GLintptr
specifying an offset in the element array buffer. Must be a valid multiple of the size of the giventype
. - 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, agl.INVALID_ENUM
error is thrown. - If
offset
is a valid multiple of the size of the given type, agl.INVALID_OPERATION
error is thrown. - If
count
orinstanceCount
are negative, agl.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
ext.drawArraysInstancedANGLE()
ext.vertexAttribDivisorANGLE()
WebGLRenderingContext.drawArrays()
WebGLRenderingContext.drawElements()
WebGL2RenderingContext.drawArraysInstanced()
WebGL2RenderingContext.vertexAttribDivisor()
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