envvars.html revision 1d8b308cbf6e17f2703807152deaa1ee075882e2 
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3<TITLE>Environment Variables</TITLE>
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9<H1>Environment Variables</H1>
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11<p>
12Mesa supports the following environment variables:
13</p>
14<ul>
15<li>MESA_NO_ASM - if set, disables all assembly language optimizations
16<li>MESA_NO_MMX - if set, disables Intel MMX optimizations
17<li>MESA_NO_3DNOW - if set, disables AMD 3DNow! optimizations
18<li>MESA_NO_SSE - if set, disables Intel SSE optimizations
19<li>MESA_DEBUG - if set, error messages are printed to stderr.
20If the value of MESA_DEBUG is "FP" floating point arithmetic errors will
21generate exceptions.
22<li>MESA_NO_DITHER - if set, disables dithering, overriding glEnable(GL_DITHER)
23<li>MESA_TEX_PROG - if set, implement conventional texture env modes with
24fragment programs (intended for developers only)
25<li>MESA_TNL_PROG - if set, implement conventional vertex transformation
26operations with vertex programs (intended for developers only).
27Setting this variable automatically sets the MESA_TEX_PROG variable as well.
28<li>MESA_EXTENSION_OVERRIDE - can be used to enable/disable extensions.
29A value such as "GL_EXT_foo -GL_EXT_bar" will enable the GL_EXT_foo extension
30and disable the GL_EXT_bar extension.
31<li>MESA_GLSL - <a href="shading.html#envvars">shading language options</a>
32</ul>
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34<p>
35The following are only applicable to the Xlib software driver.
36See the <A HREF="xlibdriver.html">Xlib software driver page</A> for details.
37</p>
38<ul>
39<li>MESA_RGB_VISUAL - specifies the X visual and depth for RGB mode
40<li>MESA_CI_VISUAL - specifies the X visual and depth for CI mode
41<li>MESA_BACK_BUFFER - specifies how to implement the back color buffer,
42    either "pixmap" or "ximage"
43<li>MESA_GAMMA - gamma correction coefficients for red, green, blue channels
44<li>MESA_XSYNC - enable synchronous X behavior (for debugging only)
45<li>MESA_GLX_FORCE_CI - if set, force GLX to treat 8bpp visuals as CI visuals
46<li>MESA_GLX_FX - set to either "fullscreen" for full-screen rendering,
47  "window" to render into a window, or "disable" to disable the Glide driver.
48<li>MESA_GLX_FORCE_ALPHA - if set, forces RGB windows to have an alpha channel.
49<li>MESA_GLX_DEPTH_BITS - specifies default number of bits for depth buffer.
50<li>MESA_GLX_ALPHA_BITS - specifies default number of bits for alpha channel.
51</ul>
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54<p>
55These environment variables are for the Intel i945/i965 drivers:
56</p>
57<ul>
58<li>INTEL_STRICT_CONFORMANCE - if set to 1, enable sw fallbacks to improve
59    OpenGL conformance.  If set to 2, always use software rendering.
60<li>INTEL_NO_BLIT - if set, disable hardware-accelerated glBitmap,
61    glCopyPixels, glDrawPixels.
62</ul>
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65<p>
66These environment variables are for the Radeon R300 driver:
67</p>
68<ul>
69<li>R300_NO_TCL - if set, disable hardware-accelerated Transform/Clip/Lighting.
70</ul>
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