WebGLRenderingContext.stencilFuncSeparate()

The WebGLRenderingContext.stencilFuncSeparate() method of the WebGL API sets the front and/or back function and reference value for stencil testing.

Stencilling enables and disables drawing on a per-pixel basis. It is typically used in multipass rendering to achieve special effects.

Syntax

void gl.stencilFuncSeparate(face, func, ref, mask);

Parameters

face
A GLenum specifying whether the front and/or back stencil state is updated. The possible values are:
  • gl.FRONT
  • gl.BACK
  • gl.FRONT_AND_BACK
func
A GLenum specifying the test function. The default function is gl.ALWAYS. The possible values are:
  • gl.NEVER:       Never pass.
  • gl.LESS:         Pass if (ref & mask) <  (stencil & mask).
  • gl.EQUAL:       Pass if (ref & mask) =  (stencil & mask).
  • gl.LEQUAL:     Pass if (ref & mask) <= (stencil & mask).
  • gl.GREATER:   Pass if (ref & mask) >  (stencil & mask).
  • gl.NOTEQUAL: Pass if (ref & mask) != (stencil & mask).
  • gl.GEQUAL:     Pass if (ref & mask) >= (stencil & mask).
  • gl.ALWAYS:     Always pass.
ref
A GLint specifying the reference value for the stencil test. This value is clamped to the range 0 to 2n -1 where n is the number of bitplanes in the stencil buffer. The default value is 0.
mask
A GLuint specifying a bit-wise mask that is used to AND the reference value and the stored stencil value when the test is done. The default value is all 1.

Return value

None.

Examples

The stencil testing is disabled by default. To enable or disable stencil testing, use the enable() and disable() methods with the argument gl.STENCIL_TEST.

gl.enable(gl.STENCIL_TEST);
gl.stencilFuncSeparate(gl.FRONT, gl.LESS, 0.2, 1110011);

To get the current stencil function, reference value, or other stencil information, query the following constants with getParameter().

gl.getParameter(gl.STENCIL_FUNC);
gl.getParameter(gl.STENCIL_VALUE_MASK);
gl.getParameter(gl.STENCIL_REF);
gl.getParameter(gl.STENCIL_BACK_FUNC);
gl.getParameter(gl.STENCIL_BACK_VALUE_MASK);
gl.getParameter(gl.STENCIL_BACK_REF);
gl.getParameter(gl.STENCIL_BITS);

Specifications

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

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome 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 25Edge Mobile Full support YesFirefox Android Full support YesOpera Android Full support 12Safari iOS Full support 8.1Samsung Internet Android Full support Yes

Legend

Full support  
Full support

See also

Document Tags and Contributors

Contributors to this page: fscholz, teoli
Last updated by: fscholz,