WebGLRenderingContext.scissor()

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The WebGLRenderingContext.scissor() method of the WebGL API sets a scissor box, which limits the drawing to a specified rectangle.

Syntax

void gl.scissor(x, y, width, height);

Parameters

x
A GLint specifying the horizontal coordinate for the lower left corner of the box. Default value: 0.
y
A GLint specifying the vertical coordinate for the lower left corner of the box. Default value: 0.
width
A non-negative Glsizei specifying the width of the scissor box. Default value: width of the canvas.
height
A non-negative Glsizei specifying the height of the scissor box. Default value: height of the canvas.

Return value

None.

Exceptions

If either width or height is a negative value, a gl.INVALID_VALUE error is thrown.

Examples

When the scissor test is enabled, only pixels within the scissor box can be modified by drawing commands.

// turn on scissor test
gl.enable(gl.SCISSOR_TEST);

// set the scissor rectangle
gl.scissor(x, y, width, height);

// execute drawing commands in the scissor box (e.g. clear)

// turn off scissor test again
gl.disable(gl.SCISSOR_TEST);

To get the current scissor box dimensions, query the SCISSOR_BOX constant which returns an Int32Array.

gl.scissor(0, 0, 200, 200);
gl.getParameter(gl.SCISSOR_BOX);
// Int32Array[0, 0, 200, 200]

Specifications

Specification Status Comment
WebGL 1.0
The definition of 'scissor' in that specification.
Recommendation Initial definition.
OpenGL ES 2.0
The definition of 'glScissor' in that specification.
Standard Man page of the OpenGL API.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
scissorChrome Full support 9Edge Full support 12Firefox Full support 4IE Full support 11Opera Full support 12Safari Full support 5.1WebView Android Full support YesChrome Android Full support 25Firefox Android Full support YesOpera Android Full support 12Safari iOS Full support 8Samsung Internet Android Full support Yes

Legend

Full support  
Full support

See also