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diff --git a/mesalib/docs/osmesa.html b/mesalib/docs/osmesa.html new file mode 100644 index 000000000..629d054f4 --- /dev/null +++ b/mesalib/docs/osmesa.html @@ -0,0 +1,88 @@ +<HTML> + +<TITLE>Off-screen Rendering</TITLE> + +<link rel="stylesheet" type="text/css" href="mesa.css"></head> + +<BODY> + +<H1>Off-screen Rendering</H1> + + +<p> +Mesa's off-screen rendering interface is used for rendering into +user-allocated blocks of memory. +That is, the GL_FRONT colorbuffer is actually a buffer in main memory, +rather than a window on your display. +There are no window system or operating system dependencies. +One potential application is to use Mesa as an off-line, batch-style renderer. +</p> + +<p> +The <B>OSMesa</B> API provides three basic functions for making off-screen +renderings: OSMesaCreateContext(), OSMesaMakeCurrent(), and +OSMesaDestroyContext(). See the Mesa/include/GL/osmesa.h header for +more information about the API functions. +</p> + +<p> +There are several examples of OSMesa in the <code>progs/osdemo/</code> +directory. +</p> + + +<H2>Deep color channels</H2> + +<p> +For some applications 8-bit color channels don't have sufficient +precision. +OSMesa supports 16-bit and 32-bit color channels through the OSMesa interface. +When using 16-bit channels, channels are GLushorts and RGBA pixels occupy +8 bytes. +When using 32-bit channels, channels are GLfloats and RGBA pixels occupy +16 bytes. +</p> + +<p> +Before version 6.5.1, Mesa had to be recompiled to support exactly +one of 8, 16 or 32-bit channels. +With Mesa 6.5.1, Mesa can be compiled for either 8, 16 or 32-bit channels +and render into any of the smaller size channels. +For example, if Mesa's compiled for 32-bit channels, you can also render +16 and 8-bit channel images. +</p> + +<p> +To build Mesa/OSMesa for 16 and 8-bit color channel support: +<pre> + make realclean + make linux-osmesa16 +</pre> + +<p> +To build Mesa/OSMesa for 32, 16 and 8-bit color channel support: +<pre> + make realclean + make linux-osmesa32 +</pre> + +<p> +You'll wind up with a library named libOSMesa16.so or libOSMesa32.so. +Otherwise, most Mesa configurations build an 8-bit/channel libOSMesa.so library +by default. +</p> + +<p> +If performance is important, compile Mesa for the channel size you're +most interested in. +</p> + +<p> +If you need to compile on a non-Linux platform, copy Mesa/configs/linux-osmesa16 +to a new config file and edit it as needed. Then, add the new config name to +the top-level Makefile. Send a patch to the Mesa developers too, if you're +inclined. +</p> + +</BODY> +</HTML> |