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      <base href="https://bugs.freedesktop.org/">
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - No pixel formats with WGL_SWAP_UNDEFINED_ARB && WGL_DOUBLE_BUFFER_ARB=true"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=100668">100668</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>No pixel formats with WGL_SWAP_UNDEFINED_ARB && WGL_DOUBLE_BUFFER_ARB=true
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>Mesa
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>17.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86 (IA32)
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Windows (All)
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>major
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Mesa core
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>mesa-dev@lists.freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>genpfault@gmail.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>mesa-dev@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I'm using llvmpipe on Windows 7 x64, though LLVM & Mesa are built for 32-bit.

Requesting WGL_SWAP_UNDEFINED_ARB or WGL_SWAP_COPY_ARB in conjunction with
WGL_DOUBLE_BUFFER_ARB = TRUE results in wglChoosePixelFormatARB() returning
zero supported pixel formats.

These attributes work:

int pixel_attributes[] =
{
    WGL_SUPPORT_OPENGL_ARB, TRUE,
    WGL_DOUBLE_BUFFER_ARB, TRUE,
    0
};

These do not:

int pixel_attributes[] =
{
    WGL_SUPPORT_OPENGL_ARB, TRUE,
    WGL_DOUBLE_BUFFER_ARB, TRUE,
    WGL_SWAP_METHOD_ARB, WGL_SWAP_UNDEFINED_ARB,
    0
};

This is causing ANGLE to fail to get a valid pixel format when using Mesa as
its OpenGL backend:
<a href="https://chromium.googlesource.com/angle/angle.git/+/master/src/libANGLE/renderer/gl/wgl/wgl_utils.cpp#35">https://chromium.googlesource.com/angle/angle.git/+/master/src/libANGLE/renderer/gl/wgl/wgl_utils.cpp#35</a></pre>
        </div>
      </p>


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