From a2ce004b2966da2fe0249e72e2fb99255cef3092 Mon Sep 17 00:00:00 2001
From: marha <marha@users.sourceforge.net>
Date: Mon, 11 Mar 2013 09:17:45 +0100
Subject: fontconfig libX11 mesa pixman xserver xkeyboard-config git update 11
 Mar 2013

xserver          commit 5047810a4c20fab444b8c6eb146c55dcdb0d4219
xkeyboard-config commit 2ed85c1e936f7cd4a9540ace5c12b9fec60ee1fb
libX11           commit 3996543c1b2919e97d61a5d70fe1ebd7cd76fc83
pixman           commit aaae3d8eefa069098e9014822817ca1429fdea46
fontconfig       commit bdf1581e3de5528f397f19bfd4ca9caaf9e7fe4a
mesa             commit b21a9d46e4be0c666327569f07b9cddeb4d42d38
---
 mesalib/docs/viewperf.html | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'mesalib/docs')

diff --git a/mesalib/docs/viewperf.html b/mesalib/docs/viewperf.html
index ab2fd67ef..3bbe1978a 100644
--- a/mesalib/docs/viewperf.html
+++ b/mesalib/docs/viewperf.html
@@ -203,6 +203,35 @@ This causes the object in question to be drawn in a strange orientation
 and with a semi-random color (between white and black) since GL_FOG is enabled.
 </p>
 
+
+<h2>Proe-05 test 1</h2>
+
+<p>
+This uses depth testing but there's two problems:
+<ol>
+<li>The glXChooseFBConfig() call doesn't request a depth buffer
+<li>The test never calls glClear(GL_DEPTH_BUFFER_BIT) to initialize the depth buffer
+</ol>
+<p>
+If the chosen visual does not have a depth buffer, you'll see the wireframe
+car model but it won't be rendered correctly.
+</p>
+If (by luck) the chosen visual has a depth buffer, its initial contents
+will be undefined so you may or may not see parts of the model.
+<p>
+Interestingly, with NVIDIA's driver most visuals happen to have a depth buffer
+and apparently the contents are initialized to 1.0 by default so this test
+just happens to work with their drivers.
+</p>
+
+<p>
+Finally, even if a depth buffer was requested and the glClear(GL_COLOR_BUFFER_BIT)
+calls were changed to glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
+the problem still wouldn't be fixed because GL_DEPTH_WRITEMASK=GL_FALSE when
+glClear is called so clearing the depth buffer would be a no-op anyway.
+</p>
+
+
 </div>
 </body>
 </html>
-- 
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