Baseline Widely available
Note: This feature is available in Web Workers.
The WebGLRenderingContext.blendEquationSeparate()
method of the WebGL API is used to set the RGB blend equation and alpha blend equation separately.
The blend equation determines how a new pixel is combined with a pixel already in the WebGLFramebuffer
.
blendEquationSeparate(modeRGB, modeAlpha)
Parameters
modeRGB
A GLenum
specifying how the red, green and blue components of source and destination colors are combined. Must be either:
gl.FUNC_ADD
: source + destination (default value),
gl.FUNC_SUBTRACT
: source - destination,
gl.FUNC_REVERSE_SUBTRACT
: destination - source,
When using the EXT_blend_minmax
extension:
ext.MIN_EXT
: Minimum of source and destination,ext.MAX_EXT
: Maximum of source and destination.When using a WebGL 2 context, the following values are available additionally:
gl.MIN
: Minimum of source and destination,gl.MAX
: Maximum of source and destination.modeAlpha
A GLenum
specifying how the alpha component (transparency) of source and destination colors are combined. Must be either:
gl.FUNC_ADD
: source + destination (default value),
gl.FUNC_SUBTRACT
: source - destination,
gl.FUNC_REVERSE_SUBTRACT
: destination - source,
When using the EXT_blend_minmax
extension:
ext.MIN_EXT
: Minimum of source and destination,ext.MAX_EXT
: Maximum of source and destination.When using a WebGL 2 context, the following values are available additionally:
gl.MIN
: Minimum of source and destination,gl.MAX
: Maximum of source and destination.None (undefined
).
If mode is not one of the three possible values, a gl.INVALID_ENUM
error is thrown.
To set the blend equations, use:
gl.blendEquationSeparate(gl.FUNC_ADD, gl.FUNC_SUBTRACT);
To get the current blend equations, query the BLEND_EQUATION
, BLEND_EQUATION_RGB
and BLEND_EQUATION_ALPHA
constants which return gl.FUNC_ADD
, gl.FUNC_SUBTRACT
, gl.FUNC_REVERSE_SUBTRACT
, or if the EXT_blend_minmax
is enabled: ext.MIN_EXT
or ext.MAX_EXT
.
gl.getParameter(gl.BLEND_EQUATION_RGB) === gl.FUNC_ADD;
// true
gl.getParameter(gl.BLEND_EQUATION_ALPHA) === gl.FUNC_ADD;
// true
Specifications Browser compatibility See also
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