WEBGL_multi_draw.multiDrawElementsWEBGL()

The WEBGL_multi_draw.multiDrawElementsWEBGL() method of the WebGL API renders multiple primitives from array data. It is identical to multiple calls to the gl.drawElements() method.

Syntax

void ext.multiDrawElementsWEBGL(mode,
    countsList, countsOffset,
    type,
    firstsList, firstsOffset,
    drawCount);

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.

countsList

An Int32Array or Array (of GLint) specifying a list of numbers of indices to be rendered.

countsOffset

A GLUint defining the starting point into the countsList array.

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

offsetsList

An Int32Array or Array (of GLsizei) specifying a list of starting indices for the arrays of vector points.

offsetsOffset

A GLuint defining the starting point into the offsetsList array.

drawCount

A GLsizei specifying the number of instances of the range 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 drawCount or items in countsList or offsetsList are negative, a gl.INVALID_VALUE error is thrown.

Examples

// let counts = new Int32Array(...);
// let offsets = new Int32Array(...);
ext.multiDrawElementsWEBGL(
    gl.TRIANGLES, counts, 0, gl.UNSIGNED_SHORT, offsets, 0, counts.length);
}

Specifications

Browser compatibility

See also

• WebGLRenderingContext.drawElements()
• WebGL2RenderingContext.drawElementsInstanced()