WebGL2RenderingContext: drawElementsInstanced() method

{{APIRef("WebGL")}}{{AvailableInWorkers}}

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

[!NOTE] When using {{domxref("WebGLRenderingContext", "WebGL 1", "", 1)}}, the {{domxref("ANGLE_instanced_arrays")}} extension can provide this method, too.

Syntax

drawElementsInstanced(mode, count, type, offset, instanceCount)

Parameters

• mode

  • : A {{domxref("WebGL_API/Types", "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 {{domxref("WebGL_API/Types", "GLsizei")}} specifying the number of elements to be rendered.

• type

  • : A {{domxref("WebGL_API/Types", "GLenum")}} specifying the type of the values in the element array buffer. Possible values are:
    • gl.UNSIGNED_BYTE
    • gl.UNSIGNED_SHORT
    • gl.UNSIGNED_INT When using the {{domxref("OES_element_index_uint")}} extension.

• offset

  • : A {{domxref("WebGL_API/Types", "GLintptr")}} specifying an offset in the element array buffer. Must be a valid multiple of the size of the given type.

• instanceCount

  • : A {{domxref("WebGL_API/Types", "GLsizei")}} specifying the number of instances of the set of elements to execute.

Return value

None ({{jsxref("undefined")}}).

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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("ANGLE_instanced_arrays.drawArraysInstancedANGLE()", "ext.drawArraysInstancedANGLE()")}}
• {{domxref("ANGLE_instanced_arrays.vertexAttribDivisorANGLE()", "ext.vertexAttribDivisorANGLE()")}}
• {{domxref("WebGLRenderingContext.drawArrays()")}}
• {{domxref("WebGLRenderingContext.drawElements()")}}
• {{domxref("WebGL2RenderingContext.drawArraysInstanced()")}}
• {{domxref("WebGL2RenderingContext.vertexAttribDivisor()")}}
• {{domxref("WEBGL_multi_draw.multiDrawElementsInstancedWEBGL()")}}