# Mesa source code tree overview

This is a brief summary of Mesa's directory tree and what's contained in each directory.

- docs - Documentation
- include - Public OpenGL header files
- src
  - egl - EGL library sources
    - docs - EGL documentation
    - drivers - EGL drivers
    - glsl - the GLSL compiler
    - main - main EGL library implementation. This is where all the EGL API functions are implemented, like eglCreateContext().
  - mesa - Main Mesa sources
    - glapi - OpenGL API dispatch layer. This is where all the GL entrypoints like glClear, glBegin, etc. are generated, as well as the GL dispatch table. All GL function calls jump through the dispatch table to functions found in main/.
    - main - The core Mesa code (mainly state management)
    - drivers - Mesa drivers (not used with Gallium)
      - common - code which may be shared by all drivers
      - dri - Direct Rendering Infrastructure drivers
        - common - code shared by all DRI drivers
        - i915 - driver for Intel i915/i945
        - i965 - driver for Intel i965
        - XXX more
      - x11 - Xlib-based software driver
      - osmesa - off-screen software driver
      - glslcompiler - a stand-alone GLSL compiler driver
      - XXX more
    - es - OpenGL ES overlay, parallelly buildable with the core Mesa
    - math - vertex array translation and transformation code (not used with Gallium)
    - ppc - Assembly code/optimizations for PPC systems (not used with Gallium)
    - shader - Vertex/fragment shader and GLSL compiler code
    - sparc - Assembly code/optimizations for SPARC systems (not used with Gallium)
    - state_tracker - State tracker / driver for Gallium. This is basically a Mesa device driver that speaks to Gallium. This directory may be moved to src/mesa/drivers/gallium at some point.
    - swrast - Software rasterization module. For drawing points, lines, triangles, bitmaps, images, etc. in software. (not used with Gallium)
    - swrast_setup - Software primitive setup. Does things like polygon culling, glPolygonMode, polygon offset, etc. (not used with Gallium)
    - tnl - Software vertex Transformation 'n Lighting. (not used with Gallium)
    - tnl_dd - TNL code for device drivers. (not used with Gallium)
    - vbo - Vertex Buffer Object code. All drawing with glBegin/glEnd, glDrawArrays, display lists, etc. goes through this module. The results is a well-defined set of vertex arrays which are passed to the device driver (or tnl module) for rendering.
    - vf - vertex format conversion (currently unused)
    - x86 - Assembly code/optimizations for 32-bit x86 systems (not used with Gallium)
    - x86-64 - Assembly code/optimizations for 64-bit x86 systems (not used with Gallium)
  - gallium - Gallium3D source code
    - include - Gallium3D header files which define the Gallium3D interfaces
    - drivers - Gallium3D device drivers
      - cell - Driver for Cell processor.
      - i915 - Driver for Intel i915/i945.
      - i965 - Driver for Intel i965.
      - llvmpipe - Software driver using LLVM for runtime code generation.
      - nv* - Drivers for NVIDIA GPUs.
      - r300 - Driver for ATI/AMD R300.
      - softpipe - Software reference driver.
      - svga - Driver for VMware's SVGA virtual GPU.
      - trace - Driver for tracing Gallium calls.
      - XXX more
    - auxiliary - Gallium support code
      - draw - Software vertex processing and primitive assembly module. This includes vertex program execution, clipping, culling and optional stages for drawing wide lines, stippled lines, polygon stippling, two-sided lighting, etc. Intended for use by drivers for hardware that does not have vertex shaders. Geometry shaders will also be implemented in this module.
      - cso_cache - Constant State Objects Cache. Used to filter out redundant state changes between state trackers and drivers.
      - gallivm - LLVM module for Gallium. For LLVM-based compilation, optimization and code generation for TGSI shaders. Incomplete.
      - pipebuffer - utility module for managing buffers
      - rbug - Gallium remote debug utility
      - rtasm - run-time assembly/machine code generation. Currently there's run-time code generation for x86/SSE, PowerPC and Cell SPU.
      - tgsi - TG Shader Infrastructure. Code for encoding, manipulating and interpretting GPU programs.
      - translate - module for translating vertex data from one format to another.
      - util - assorted utilities for arithmetic, hashing, surface creation, memory management, 2D blitting, simple rendering, etc.
    - state_trackers -
      - dri - Meta state tracker for DRI drivers
      - egl - Meta state tracker for EGL drivers
      - es - OpenGL ES 1.x and 2.x state trackers
      - g3dvl -
      - glx - Meta state tracker for GLX
      - python -
      - vega - OpenVG 1.x state tracker
      - wgl -
      - xorg - Meta state tracker for Xorg video drivers
    - winsys -
      - drm -
      - g3dvl -
      - gdi -
      - xlib -
  - glu - The OpenGL Utility library
    - sgi - GLU from SGI
    - mesa - Mesa version of GLU (deprecated)
  - glut - Mark Kilgard's OpenGL OpenGL Utility Toolkit library
  - glx - The GLX library code for building libGL. This is used for direct rendering drivers. It will dynamically load one of the xxx_dri.so drivers.
  - glw - Widgets for Xt/Motif.
  - glew - OpenGL Extension Wrangler library (used by demo programs)
- progs - OpenGL test and demonstration programs
- lib - where the GL libraries are placed