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- <title>Shading Language Support</title>
+ <title>Shading Language</title>
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<body>
<div class="header">
- <h1>The Mesa 3D Graphics Library</h1>
+ The Mesa 3D Graphics Library
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<div class="content">
-<h1>Shading Language Support</h1>
+<h1>Shading Language</h1>
<p>
This page describes the features and status of Mesa's support for the
<li><b>nopfrag</b> - force fragment shader to be a simple shader that passes
through the color attribute.
<li><b>useprog</b> - log glUseProgram calls to stderr
+<li><b>errors</b> - GLSL compilation and link errors will be reported to stderr.
</ul>
<p>
Example: export MESA_GLSL=dump,nopt
</p>
+<h3 id="replacement">Experimenting with Shader Replacements</h3>
<p>
Shaders can be dumped and replaced on runtime for debugging purposes. This
feature is not currently supported by SCons build.
This is controlled via following environment variables:
+</p>
<ul>
<li><b>MESA_SHADER_DUMP_PATH</b> - path where shader sources are dumped
<li><b>MESA_SHADER_READ_PATH</b> - path where replacement shaders are read
When both are set, these paths should be different so the dumped shaders do
not clobber the replacement shaders. Also, the filenames of the replacement shaders
should match the filenames of the corresponding dumped shaders.
+
+<h3 id="capture">Capturing Shaders</h3>
+
+<p>
+Setting <b>MESA_SHADER_CAPTURE_PATH</b> to a directory will cause the compiler
+to write <code>.shader_test</code> files for use with
+<a href="https://gitlab.freedesktop.org/mesa/shader-db">shader-db</a>, a tool
+which compiler developers can use to gather statistics about shaders
+(instructions, cycles, memory accesses, and so on).
+</p>
+<p>
+Notably, this captures linked GLSL shaders - with all stages together -
+as well as ARB programs.
</p>
<h2 id="support">GLSL Version</h2>
<li>Use the built-in library functions whenever possible.
For example, instead of writing this:
<pre>
- float x = 1.0 / sqrt(y);
+float x = 1.0 / sqrt(y);
</pre>
Write this:
<pre>
- float x = inversesqrt(y);
+float x = inversesqrt(y);
</pre>
</li>
</ul>