WebGLRenderingContext: drawArrays() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Note: This feature is available in Web Workers.

The WebGLRenderingContext.drawArrays() method of the WebGL API renders primitives from array data.

Syntax

js
drawArrays(mode, first, count)

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.

Note: If mode is POINTS, gl_PointSize may need to be set for drawArrays to render, as its value is unknown if not explicitly written. Only some GPUs set its default as 1.0.

first

A GLint specifying the starting index in the array of vector points.

count

A GLsizei specifying the number of indices to be rendered.

Return value

None (undefined).

Exceptions

  • If mode is not one of the accepted values, a gl.INVALID_ENUM error is thrown.
  • If first or count are negative, a gl.INVALID_VALUE error is thrown.
  • if gl.CURRENT_PROGRAM is null, a gl.INVALID_OPERATION error is thrown.

Examples

js
gl.drawArrays(gl.POINTS, 0, 8);

Specifications

Specification
WebGL Specification
# 5.14.11

Browser compatibility

BCD tables only load in the browser

See also