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WEBGL_multi_draw: multiDrawArraysInstancedWEBGL() method

files/en-us/web/api/webgl_multi_draw/multidrawarraysinstancedwebgl/index.md

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{{APIRef("WebGL")}}

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

js-nolint
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

  • 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

js
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

{{Specifications}}

Browser compatibility

{{Compat}}

See also