# Performance Tips

Performance tips for software rendering:

1. Turn off smooth shading when you don't need it (glShadeModel)
2. Turn off depth buffering when you don't need it.
3. Turn off dithering when not needed.
4. Use double buffering as it's often faster than single buffering
5. Compile in the X Shared Memory extension option if it's supported on your system by adding -DSHM to CFLAGS and -lXext to XLIBS for your system in the Make-config file.
6. Recompile Mesa with more optimization if possible.
7. Try to maximize the amount of drawing done between glBegin/glEnd pairs.
8. Use the MESA_BACK_BUFFER variable to find best performance in double buffered mode. (X users only)
9. Optimized polygon rasterizers are employed when: rendering into back buffer which is an XImage RGB mode, not grayscale, not monochrome depth buffering is GL_LESS, or disabled flat or smooth shading dithered or non-dithered no other rasterization operations enabled (blending, stencil, etc)
10. Optimized line drawing is employed when: rendering into back buffer which is an XImage RGB mode, not grayscale, not monochrome depth buffering is GL_LESS or disabled flat shading dithered or non-dithered no other rasterization operations enabled (blending, stencil, etc)
11. Textured polygons are fastest when: using a 3-component (RGB), 2-D texture minification and magnification filters are GL_NEAREST texture coordinate wrap modes for S and T are GL_REPEAT GL_DECAL environment mode glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST ) depth buffering is GL_LESS or disabled
12. Lighting is fastest when: Two-sided lighting is disabled GL_LIGHT_MODEL_LOCAL_VIEWER is false GL_COLOR_MATERIAL is disabled No spot lights are used (all GL_SPOT_CUTOFFs are 180.0) No local lights are used (all position W's are 0.0) All material and light coefficients are >= zero
13. XFree86 users: if you want to use 24-bit color try starting your X server in 32-bit per pixel mode for better performance. That is, start your X server with startx -- -bpp 32 instead of startx -- -bpp 24
14. Try disabling dithering with the MESA_NO_DITHER environment variable. If this env var is defined Mesa will disable dithering and the command glEnable(GL_DITHER) will be ignored.