Revision 1018326 of EXT_frag_depth

<div>{{APIRef("WebGL")}}</div>

<p>The <code><strong>EXT_frag_depth</strong></code> extension is part of the <a href="/en-US/docs/Web/API/WebGL_API">WebGL API</a> and enables to set a depth value of a fragment from within the fragment shader.</p>

<p>WebGL extensions are available using the {{domxref("WebGLRenderingContext.getExtension()")}} method. For more information, see also <a href="/en-US/docs/Web/API/WebGL_API/Using_Extensions">Using Extensions</a> in the <a href="/en-US/docs/Web/API/WebGL_API/Tutorial">WebGL tutorial</a>.</p>

<div class="note">
<p><strong>Availability:</strong> This extension is only available to {{domxref("WebGLRenderingContext", "WebGL1", "", 1)}} contexts. In {{domxref("WebGL2RenderingContext", "WebGL2", "", 1)}}, the functionality of this extension is available on the WebGL2 context by default.</p>
</div>

<h2>Examples</h2>

<p>Enable the extension:</p>

<pre class="brush: js">
gl.getExtension("EXT_frag_depth");</pre>

<p>With the built-in output variable <code>gl_FragDepthEXT</code>, you can now set a depth value of a fragment from within the fragment shader:</p>

<pre class="brush: html">
&lt;script type="x-shader/x-fragment"&gt;
void main(){
  gl_FragColor = vec4(1.0, 0.0, 1.0, 1.0); 
  gl_FragDepthEXT = 0.5; 
}
&lt;/script&gt;</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('EXT_frag_depth', "", "EXT_frag_depth")}}</td>
   <td>{{Spec2('EXT_frag_depth')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoDesktop("30.0")}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{domxref("WebGLRenderingContext.getExtension()")}}</li>
</ul>