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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/api/webglrenderingcontext/blendequationseparate | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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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 +--- +<div>{{APIRef("WebGL")}}</div> + +<p>The <strong><code>WebGLRenderingContext.blendEquationSeparate()</code></strong> method of the <a href="/en-US/docs/Web/API/WebGL_API">WebGL API</a> is used to set the RGB blend equation and alpha blend equation separately.</p> + +<p>The blend equation determines how a new pixel is combined with a pixel already in the {{domxref("WebGLFramebuffer")}}.</p> + +<h2 id="Syntax">Syntax</h2> + +<pre class="syntaxbox">void <var>gl</var>.blendEquationSeparate(<var>modeRGB, modeAlpha</var>); +</pre> + +<h3 id="Parameters">Parameters</h3> + +<dl> + <dt><code>modeRGB</code></dt> + <dd>A {{domxref("GLenum")}} specifying how the red, green and blue components of source and destination colors are combined. Must be either: + <ul> + <li><code>gl.FUNC_ADD</code>: source + destination (default value),</li> + <li><code>gl.FUNC_SUBTRACT</code>: source - destination,</li> + <li><code>gl.FUNC_REVERSE_SUBTRACT</code>: destination - source,</li> + <li>When using the {{domxref("EXT_blend_minmax")}} extension: + <ul> + <li><code>ext.MIN_EXT</code>: Minimum of source and destination,</li> + <li><code>ext.MAX_EXT</code>: Maximum of source and destination.</li> + </ul> + </li> + <li>When using a {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, the following values are available additionally: + <ul> + <li><code>gl.MIN</code>: Minimum of source and destination,</li> + <li><code>gl.MAX</code>: Maximum of source and destination.</li> + </ul> + </li> + </ul> + </dd> + <dt><code>modeAlpha</code></dt> + <dd>A {{domxref("GLenum")}} specifying how the alpha component (transparency) of source and destination colors are combined. Must be either: + <ul> + <li><code>gl.FUNC_ADD</code>: source + destination (default value),</li> + <li><code>gl.FUNC_SUBTRACT</code>: source - destination,</li> + <li><code>gl.FUNC_REVERSE_SUBTRACT</code>: destination - source,</li> + <li>When using the {{domxref("EXT_blend_minmax")}} extension: + <ul> + <li><code>ext.MIN_EXT</code>: Minimum of source and destination,</li> + <li><code>ext.MAX_EXT</code>: Maximum of source and destination.</li> + </ul> + </li> + <li>When using a {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, the following values are available additionally: + <ul> + <li><code>gl.MIN</code>: Minimum of source and destination,</li> + <li><code>gl.MAX</code>: Maximum of source and destination.</li> + </ul> + </li> + </ul> + </dd> +</dl> + +<h3 id="Return_value">Return value</h3> + +<p>None.</p> + +<h3 id="Exceptions">Exceptions</h3> + +<p>If <em>mode</em> is not one of the three possible values, a <code>gl.INVALID_ENUM</code> error is thrown.</p> + +<h2 id="Examples">Examples</h2> + +<p>To set the blend equations, use:</p> + +<pre class="brush: js">gl.blendEquationSeparate(gl.FUNC_ADD, gl.FUNC_SUBTRACT); +</pre> + +<p>To get the current blend equations, query the <code>BLEND_EQUATION</code>, <code>BLEND_EQUATION_RGB</code> and <code>BLEND_EQUATION_ALPHA</code> constants which return <code>gl.FUNC_ADD</code>, <code>gl.FUNC_SUBTRACT</code>, <code>gl.FUNC_REVERSE_SUBTRACT</code>, or if the {{domxref("EXT_blend_minmax")}} is enabled: <code>ext.MIN_EXT</code> or <code>ext.MAX_EXT</code>.</p> + +<pre class="brush: js">gl.getParameter(gl.BLEND_EQUATION_RGB) === gl.FUNC_ADD; +// true + +gl.getParameter(gl.BLEND_EQUATION_ALPHA) === gl.FUNC_ADD; +// true +</pre> + +<h2 id="Specifications">Specifications</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + <tr> + <td>{{SpecName('WebGL', "#5.14.3", "blendEquationSeparate")}}</td> + <td>{{Spec2('WebGL')}}</td> + <td>Initial definition for WebGL.</td> + </tr> + <tr> + <td>{{SpecName('OpenGL ES 2.0', "glBlendEquationSeparate.xml", "glBlendEquationSeparate")}}</td> + <td>{{Spec2('OpenGL ES 2.0')}}</td> + <td>Man page of the OpenGL ES 2.0 API.</td> + </tr> + <tr> + <td>{{SpecName('OpenGL ES 3.0', "glBlendEquationSeparate.xhtml", "glBlendEquationSeparate")}}</td> + <td>{{Spec2('OpenGL ES 3.0')}}</td> + <td>Man page of the OpenGL ES 3.0 API.</td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility">Browser compatibility</h2> + +<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p> + +<p>{{Compat("api.WebGLRenderingContext.blendEquationSeparate")}}</p> + +<h2 id="See_also">See also</h2> + +<ul> + <li>{{domxref("WebGLRenderingContext.blendEquation()")}}</li> + <li>{{domxref("WebGLRenderingContext.blendColor()")}}</li> + <li>{{domxref("WebGLRenderingContext.blendFunc()")}}</li> + <li>{{domxref("EXT_blend_minmax")}}</li> +</ul> |