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<base href="https://bugzilla.icculus.org/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - OpenGL2: Add r_ignoreDstAlpha"
href="https://bugzilla.icculus.org/show_bug.cgi?id=6077">6077</a>
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<th>Summary</th>
<td>OpenGL2: Add r_ignoreDstAlpha
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr>
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<th>Product</th>
<td>ioquake3
</td>
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<th>Version</th>
<td>GIT MASTER
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>minor
</td>
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<th>Priority</th>
<td>P3
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<th>Component</th>
<td>Video
</td>
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<th>Assignee</th>
<td>zachary@ioquake.org
</td>
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<th>Reporter</th>
<td>use.less01@gmail.com
</td>
</tr>
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<th>QA Contact</th>
<td>quake3-bugzilla@icculus.org
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<p>
<div>
<pre>OpenGL2 uses a RGBA16F framebuffer when rendering in HDR. This was changed
from a RGB16F framebuffer because the former is 64bpp and four-byte aligned,
whereas the latter is 48bpp and not. Not being four-byte aligned lead to
problems on certain hardware.
OpenGL1 doesn't require an alpha channel for its framebuffer, but certain
material shaders are written as if it did, utilizing GL_DST_ALPHA and
GL_ONE_MINUS_DST_ALPHA.
This lead to certain materials looking different between the two renderers.
This patch adds a cvar to OpenGL2, r_IgnoreDstAlpha, default 1. When on, this
causes parsed material shaders to treat GL_DST_ALPHA and GL_ONE_MINUS_DST_ALPHA
as GL_ONE and GL_ZERO, respectively. This reproduces the behaviour of having
no alpha channel in OpenGL2, and can be turned off if material shaders
expecting the alpha channel are used.</pre>
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