WebGLRenderingContext: drawArrays() method

Available in workers

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

Syntax

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

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

Specifications

Browser compatibility

See also

• drawElements()
• ext.drawArraysInstancedANGLE()
• ext.drawElementsInstancedANGLE()
• ext.vertexAttribDivisorANGLE()
• drawArraysInstanced()
• drawElementsInstanced()
• vertexAttribDivisor()
• multiDrawArraysWEBGL()