From 33058f2b292b3a581333bdfb21b8f671898c5060 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:40:17 -0500 Subject: initial commit --- .../blendequationseparate/index.html | 126 +++++++++++++++++++++ 1 file changed, 126 insertions(+) create mode 100644 files/zh-cn/web/api/webglrenderingcontext/blendequationseparate/index.html (limited to 'files/zh-cn/web/api/webglrenderingcontext/blendequationseparate') diff --git a/files/zh-cn/web/api/webglrenderingcontext/blendequationseparate/index.html b/files/zh-cn/web/api/webglrenderingcontext/blendequationseparate/index.html new file mode 100644 index 0000000000..e274a77dde --- /dev/null +++ b/files/zh-cn/web/api/webglrenderingcontext/blendequationseparate/index.html @@ -0,0 +1,126 @@ +--- +title: WebGLRenderingContext.blendEquationSeparate() +slug: Web/API/WebGLRenderingContext/blendEquationSeparate +translation_of: Web/API/WebGLRenderingContext/blendEquationSeparate +--- +
{{APIRef("WebGL")}}
+ +

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 {{domxref("WebGLFramebuffer")}}.

+ +

Syntax

+ +
void gl.blendEquationSeparate(modeRGB, modeAlpha);
+
+ +

Parameters

+ +
+
modeRGB
+
A {{domxref("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 {{domxref("EXT_blend_minmax")}} extension: +
      +
    • ext.MIN_EXT: Minimum of source and destination,
      • +
    • ext.MAX_EXT: Maximum of source and destination.
      • +
    +
    • +
  • When using a {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, the following values are available additionally: +
      +
    • gl.MIN: Minimum of source and destination,
      • +
    • gl.MAX: Maximum of source and destination.
      • +
    +
    • +
+
+
modeAlpha
+
A {{domxref("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 {{domxref("EXT_blend_minmax")}} extension: +
      +
    • ext.MIN_EXT: Minimum of source and destination,
      • +
    • ext.MAX_EXT: Maximum of source and destination.
      • +
    +
    • +
  • When using a {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, the following values are available additionally: +
      +
    • gl.MIN: Minimum of source and destination,
      • +
    • gl.MAX: Maximum of source and destination.
      • +
    +
    • +
+
+
+ +

Return value

+ +

None.

+ +

Exceptions

+ +

If mode is not one of the three possible values, a gl.INVALID_ENUM error is thrown.

+ +

Examples

+ +

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 {{domxref("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

+ + + + + + + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('WebGL', "#5.14.3", "blendEquationSeparate")}}{{Spec2('WebGL')}}Initial definition for WebGL.
{{SpecName('OpenGL ES 2.0', "glBlendEquationSeparate.xml", "glBlendEquationSeparate")}}{{Spec2('OpenGL ES 2.0')}}Man page of the OpenGL ES 2.0 API.
{{SpecName('OpenGL ES 3.0', "glBlendEquationSeparate.xhtml", "glBlendEquationSeparate")}}{{Spec2('OpenGL ES 3.0')}}Man page of the OpenGL ES 3.0 API.
+ +

Browser compatibility

+ + + +

{{Compat("api.WebGLRenderingContext.blendEquationSeparate")}}

+ +

See also

+ + -- cgit v1.2.3-54-g00ecf