GL4ES is a GL 1.5 to GL ES 1.1 translation, with support for Pandora, ODroid, CHIP, Raspberry PI and Android.
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README.md

gl4es

This is a library providing OpenGL 1.x functionality for OpenGL ES accelerated hardware.

This is a fork a glshim (https://github.com/lunixbochs/glshim). Go check this lib if you need things like RemoteGL or if need support for TinyGLES (for 100% software rendering).

The focusse is on compatibility with a wide selection of game and software, as well as speed.

It has been tested successfully of a large selection of games and software, including: Mincraft, OpenMW, SeriousSam, RVGL, TSMC, TORCS, SpeedDreams, GL-117, Blender 2.68 and many more.

Most function of OpenGL up to 1.5 are supported, with some notable exceptions:

  • Reading of Depth or Stencil buffer will not work
  • GL_FEEDBACK mode is not implemented

Some know limitations:

  • GL_SELECT as some limitation in its implementation (for exemple, current Depth buffer or binded texture are not taken into account)
  • NPOT texture are supported, but not with GL_REPEAT / GL_MIRRORED, only GL_CLAMP will work properly (unless the GLES Hardware support NPOT)
  • Framebuffer use FRAMEBUFFER_OES extension (that must be present in the GLES 1.1 stack)
  • Multiple Color attachment on Framebuffer are not supported
  • OcclusionQuery is implemented, but with a 0 bits precision
  • Probably many other things

Compiling

for Pandora

cmake . -DPANDORA=1; make GL

or for the Raspberry Pi

cmake . -DBCMHOST=1; make GL

or for the ODroid

cmake . -DODROID=1; make GL

or for CHIP machines

cmake . -DCHIP=1; make GL

or for Android

An Android.mk is provided that should compile with an NDK

or use ccmake

Alternatively, you can use the curses-bases ccmake (or any other gui frontend for cmake) to select wich platform to use interactively.


GLU

Standard GLU do works without any issues.


Installation

Put lib/libGL.so.1 in your LD_LIBRARY_PATH.


Usage

There are many environnement variable to control gl4es behavour. All are numeric, except LIBGL_VERSION that take a string.

LIBGL_FB

Controls the Framebuffer output

  • 0 : Default, using standard x11 rendering
  • 1 : Use Framebuffer output (x11 bypassed, only fullscreen)
  • 2 : Use Framebuffer, but also an intermediary FBO
  • 3 : Use PBuffer, allowing x11 (and windowed) rendering even if driver doesn't support it
LIBGL_XREFRESH

Debug helper in specific cases

  • 0 : Default, nothing special
  • 1 : xrefresh will be called on cleanup
LIBGL_STACKTRACE

Automatic Backtrace log

  • 0 : Default, nothing special
  • 1 : stacktrace will be printed on crash
LIBGL_VSYNC

VSync control

  • 0 : Default, nothing special
  • 1 : vsync enabled
LIBGL_RECYCLEFBO

Recycling FBO special case (don't delete a created FBO, but recycle it if needed)

  • 0 : Default, nothing special
  • 1 : Recycling of FBO enabled
LIBGL_MIPMAP

Handling of Manual and Automatic MIPMAP

  • 0 : Default, nothing special
  • 1 : AutoMipMap forced
  • 2 : guess AutoMipMap (based on manual mipmaping on textures)
  • 3 : ignore MipMap (mipmap creation / use entirely disabled)
  • 4 : ignore AutoMipMap on non-squared textures
LIBGL_TEXCOPY

Make a local copy of every texture for easy glGetTexImage2D

  • 0 : Default, nothing special
  • 1 : Texture copy enabled
LIBGL_SHRINK

Texture shrinking control

  • 0 : Default, nothing special
  • 1 : everything / 2 (using original algorithm for size reduction, all other shink mode use a refined algorithm)
  • 2 : only textures wich one size > 512 are / 2
  • 3 : only textures wich one size > 256 are / 2
  • 4 : only textures wich one size > 256 are / 2, and the one > 1024 are / 4
  • 5 : only textures wich one size > 256 are resized to 256 (if possible, because only /2 and /4 exists), but empty texture are not shrinked
  • 6 : only textures wich one size > 128 are / 2, thoses >= 512 are resized to 256 (if possible, because only /2 and /4 exists), but empty texture are not shrinked
  • 7 : only textures wich one size > 512 are / 2, but empty texture are not shrinked
  • 8 : advertise a max texture size of 8192, but every texture wich one size > 2048 are shrinked to 2048
  • 9 : advertise a max texture size of 8192, but every texture wich one size > 4096 are / 4 and the one > 512 are / 2, but empty texture are not shrinked
  • 10: advertise a max texture size of 8192, but every texture wich one size > 2048 are / 4 and the one > 512 are / 2, but empty texture are not shrinked
LIBGL_TEXDUMP

Texture dump

  • 0 : Default, nothing special
  • 1 : Texture dump enabled
LIBGL_ALPHAHACK

Experimental: enable Alpha test only when using texture that contains an alpha channel

  • 0 : Default, nothing special
  • 1 : Alpha Hack enabled
LIBGL_NODOWNSAMPLING

Texture downsampling control

  • 0 : Default, DXTc texture are downsampled to 16bits
  • 1 : DXTc texture are left as 32bits RGBA
LIBGL_STREAM

PANDORA only: enable Texture Streaming (works only on RGB textures)

  • 0 : Default, nothing special
  • 1 : Enabled on empty RGB textures
  • 2 : Enabled on all RGB textures
LIBGL_COPY

Control the glCopyTex(Sub)Image2D hack (they are buggy on pandora and don't work most of the time)

  • 0 : Don't use native glCopyTex(Sub)Image2D, but a workaround function using FBO
  • 1 : No glCopyTexImage2D / glCopyTexSubImage2D hack, use native ones
LIBGL_NOLUMALPHA

Control the availability of the LUMUNANCE_ALPHA format (can be buggy on Pandora model CC)

  • 0 : Default,GL_LUMINANCE_ALPHA is available and used if needed
  • 1 : GL_LUMINANCE_ALPHA hardware support disabled (a GL_RGBA texture will be used instead)
LIBGL_BLENDHACK

Experimental: Change Blend GL_SRC_ALPHA, GL_ONE to GL_ONE, GL_ONE

  • 0 : Default, nothing special
  • 1 : Change Blend GL_SRC_ALPHA, GL_ONE to GL_ONE, GL_ONE (can be usefull for Xash3D engine)
LIBGL_BLENDCOLOR

Hack: Export a (faked) glBlendColor

  • 0 : Default, don't expose gBlendColor
  • 1 : Exposed the function (if no hadware support, faked function willbe used)
LIBGL_VERSION

Hack: Control the glGetString version. Overide version string (should be in the form of "1.x")

LIBGL_BATCH

Experimental: Batch mode (fuse of contigous Display list, to limit Draw calls)

  • 0 : Default, only Draw list created during a glList are fused (i.e. contigous glBegin / glEnd inside a List)
  • 1 : Force a maximum of call to be batched (like if all was inside a big glList)
  • 2 : Disable Batch mode completly, no fuse of draw list
LIBGL_NOERROR

Hack: glGetError() always return GL_NOERROR

  • 0 : Default, glGetError behave as it should
  • 1 : glGetError never fail.
LIBGL_GAMMA

Pandora Hack: Set a Gamma value (in decimal formal, 1.0 means no gamma boost)

  • X.Y : Use X.Y as gamma when creating context (typical value can be 1.6 or 2.0)
LIBGL_SRGB

ODROID Hack: Enable sRGB Surface (so Gamma corrected), if Hardware support it

  • 0 : Default, don't try to use sRGB surface
  • 1 : Enable sRGB Surface (but support will be tested first, must have EGL_KHR_gl_colorspace extension)
LIBGL_FASTMATH

Hack: Activate some Fast Math in processor/coprocessor

  • 0 : Default, nothing special
  • 1 : On OpenPandora, activate "RunFast" on Cortex-A8 (mode default NaN, flush-to-zero) : Not implemented on other platforms (will do nothing)
LIBGL_SILENTSTUB

Debug: Hide or Show the Sub / Not found message

  • 0 : Default, the messages are shown
  • 1 : Silent, don't print the STUB or glXGetProcAddress glXXXXX not found message
LIBGL_NOBANNER

Show/Hide initial text

  • 0 : Default, print starting message
  • 1 : Silent: no LIBGL message at start (combile with LIBGL_SILENTSTUB for more silence)
LIBGL_NPOT

Expose NPOT (Non Power of Two) Support

  • 0 : Default, don't expose the extension (but npot are still supported)
  • 1 : Expose limited NPOT extension
  • 2 : Expose GL_ARB_texture_non_power_of_two extension
LIBGL_GLQUERIES

Expose glQueries functions

  • 0 : Don't expose the function (fake one will be used if called)
  • 1 : Default, expose fake functions (always answer 0)
LIBGL_NOTEXMAT

Handling of Texture Matrix

  • 0 : Default, perform handling internaly (better handling of NPOT texture on all hardware)
  • 1 : Let the driver handle texmat (can be faster in some cases, but NPOT texture may be broken)
LIBGL_NOTEST

Initial Hardware test

  • 0 : Default, perform intial hardware testing (using a PBuffer)
  • 1 : Do not perform test (no extensions tested or used)

Version history

current version
  • Fixed (Added in fact) support for Multisampling on the GLX Context creation (a bit hacky, but seems to works)
  • Added LIBGL_NODOWNSAMPLING and associated Hint
0.9.3
  • Added support for Cube Mapping (with hardware support)
  • Improved Texture state tracking
  • Added LIBGL_NOTEXMAT env. var. switch for Texture Matrix handling
  • Added GL_EXT_vertex_array_bgra (and NEONinzed some loop)
  • Finished GL_EXT_direct_state_access extension
  • Mangled glX function (to be abble to use apitrace to capture GL frames)
  • Return some values in glXQueryServerString, coherent with glXGetClientString
0.9.2
  • All matrix are tracked now
  • Texture Matrix are 100% handled by gl4es. GLES Hardware keep an Identity matrix (TexCoord are transformed if needed). This allows a better handling of NPOT texture on hadware that doesn't support Full NPOT (fixed movies beiing horizontaly shifted in openmw with LIBGL_NPOT=1 for example)
0.9.1
  • Added gl4es specifics glHint capabilities. If the extension GL_GL4ES_hint is present, than a few Hint are accessible. Look in include/gl4eshint.h for the list.
0.9.0
  • New name: gl4es