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      5   <title>Off-screen Rendering</title>
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     10 <div class="header">
     11   <h1>The Mesa 3D Graphics Library</h1>
     12 </div>
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     15 <div class="content">
     16 
     17 <h1>Off-screen Rendering</h1>
     18 
     19 
     20 <p>
     21 Mesa's off-screen interface is used for rendering into user-allocated memory
     22 without any sort of window system or operating system dependencies.
     23 That is, the GL_FRONT colorbuffer is actually a buffer in main memory,
     24 rather than a window on your display.
     25 </p>
     26 
     27 <p>
     28 The OSMesa API provides three basic functions for making off-screen
     29 renderings: OSMesaCreateContext(), OSMesaMakeCurrent(), and
     30 OSMesaDestroyContext().  See the Mesa/include/GL/osmesa.h header for
     31 more information about the API functions.
     32 </p>
     33 
     34 <p>
     35 The OSMesa interface may be used with any of three software renderers:
     36 </p>
     37 <ol>
     38 <li>llvmpipe - this is the high-performance Gallium LLVM driver
     39 <li>softpipe - this it the reference Gallium software driver
     40 <li>swrast - this is the legacy Mesa software rasterizer
     41 </ol>
     42 
     43 
     44 <p>
     45 There are several examples of OSMesa in the mesa/demos repository.
     46 </p>
     47 
     48 <h1>Building OSMesa</h1>
     49 
     50 <p>
     51 Configure and build Mesa with something like:
     52 
     53 <pre>
     54 configure --enable-osmesa --disable-driglx-direct --disable-dri --with-gallium-drivers=swrast
     55 make
     56 </pre>
     57 
     58 <p>
     59 Make sure you have LLVM installed first if you want to use the llvmpipe driver.
     60 </p>
     61 
     62 <p>
     63 When the build is complete you should find:
     64 </p>
     65 <pre>
     66 lib/libOSMesa.so  (swrast-based OSMesa)
     67 lib/gallium/libOSMsea.so  (gallium-based OSMesa)
     68 </pre>
     69 
     70 <p>
     71 Set your LD_LIBRARY_PATH to point to one directory or the other to select
     72 the library you want to use.
     73 </p>
     74 
     75 <p>
     76 When you link your application, link with -lOSMesa
     77 </p>
     78 
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