WEBGL_multi_draw.multiDrawArraysInstancedWEBGL()

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

Syntax

multiDrawArraysInstancedWEBGL(mode,
    firstsList, firstsOffset,
    countsList, countsOffset,
    instanceCountsList, instanceCountsOffset,
    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.
firstsList

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

firstsOffset

A GLuint defining the starting point into the firstsLists array.

countsList

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

countsOffset

A GLuint defining the starting point into the countsList array.

instanceCountsList

An Int32Array or Array (of GLsizei) specifying a list of numbers of instances of the range of elements to execute.

instanceCountsOffset

A GLuint defining the starting point into the instanceCountsList 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 firstsList, countsList, or instanceCountsList are negative, a gl.INVALID_VALUE error is thrown.
  • if gl.CURRENT_PROGRAM is null, a gl.INVALID_OPERATION error is thrown.

Examples

const firsts = new Int32Array(/* … */);
const counts = new Int32Array(/* … */);
const instanceCounts = new Int32Array(/* … */);
ext.multiDrawArraysInstancedWEBGL(
   gl.TRIANGLES, firsts, 0, counts, 0, instanceCounts, 0, firsts.length);

Specifications

Specification
WebGL WEBGL_multi_draw Extension Specification

Browser compatibility

BCD tables only load in the browser

See also