Erik Faye-Lund | 4d06683 | 2020-06-12 20:09:42 +0200 | [diff] [blame] | 1 | Off-screen Rendering |
| 2 | ==================== |
| 3 | |
| 4 | Mesa's off-screen interface is used for rendering into user-allocated |
| 5 | memory without any sort of window system or operating system |
| 6 | dependencies. That is, the GL_FRONT colorbuffer is actually a buffer in |
| 7 | main memory, rather than a window on your display. |
| 8 | |
| 9 | The OSMesa API provides three basic functions for making off-screen |
| 10 | renderings: OSMesaCreateContext(), OSMesaMakeCurrent(), and |
| 11 | OSMesaDestroyContext(). See the Mesa/include/GL/osmesa.h header for more |
| 12 | information about the API functions. |
| 13 | |
| 14 | The OSMesa interface may be used with any of three software renderers: |
| 15 | |
| 16 | #. llvmpipe - this is the high-performance Gallium LLVM driver |
| 17 | #. softpipe - this it the reference Gallium software driver |
| 18 | #. swrast - this is the legacy Mesa software rasterizer |
| 19 | |
| 20 | There are several examples of OSMesa in the mesa/demos repository. |
| 21 | |
| 22 | Building OSMesa |
| 23 | --------------- |
| 24 | |
| 25 | Configure and build Mesa with something like: |
| 26 | |
| 27 | :: |
| 28 | |
| 29 | meson builddir -Dosmesa=gallium -Dgallium-drivers=swrast -Ddri-drivers=[] -Dvulkan-drivers=[] -Dprefix=$PWD/builddir/install |
| 30 | ninja -C builddir install |
| 31 | |
| 32 | Make sure you have LLVM installed first if you want to use the llvmpipe |
| 33 | driver. |
| 34 | |
| 35 | When the build is complete you should find: |
| 36 | |
| 37 | :: |
| 38 | |
| 39 | $PWD/builddir/install/lib/libOSMesa.so (swrast-based OSMesa) |
| 40 | $PWD/builddir/install/lib/gallium/libOSMsea.so (gallium-based OSMesa) |
| 41 | |
| 42 | Set your LD_LIBRARY_PATH to point to $PWD/builddir/install to use the |
| 43 | libraries |
| 44 | |
| 45 | When you link your application, link with -lOSMesa |