Regal

https://github.com/p3/regal

Downloads, Issues, Commits.

Status:

Recent News

• November 2013 - Regal Wrangler support added.
• October 2013 - Emscripten support added.
• July 2013 - New binaries available for Windows and Mac.
• July 2013 - OpenGL 4.4 API support added.
• July 2013 - apitrace support added.

Summary

Regal is a user-space OpenGL layer for OpenGL 2.x, 3.x, 4.x, Core contexts and ES 2.0. Regal implements OpenGL loading, emulation for ES and Core contexts and tools for debugging.

Status

Regal has been in active development on github since May of 2012 --- it is in deployment for internal projects, and has received significant external contributions.

Features such as emulation might not be complete or bug-free enough for every situation, mileage may vary, contributions welcome.

Contents

• Regal
  • Recent News
  • Summary
  • Status
  • Goals
  • Deployment
  • Downloads
  • Features
    • Emulation
    • OpenGL error checking
    • Logging
    • Multi-threading support
    • Spoofing OpenGL vendor, renderer, version and extension strings
    • Browser-based interface
    • Regal OpenGL extensions
  • Regal API
  • In Progress
  • Planned Features
  • Limitations
  • Contact Information
  • Other Information
  • Platform Notes
    • Windows
    • Linux
    • OS X
    • Android
    • iOS
    • PPAPI and NaCl
  • Questions and Answers
    • STL, Standard C++ Library, Boost
    • Alternatives for OpenGL Loading
    • Related Efforts
  • License and Credits

Goals

Regal is a portable OpenGL layer on top of existing OpenGL implementations. Compile and link an app against Regal and deploy on various OpenGL implementations including compatibility, core and ES 2.0 OpenGL contexts.

• Portability

  Consistent OpenGL API that runs on all major platforms: Windows, Linux, Mac, iOS, and Android

• Compatible

  Immediate mode, fixed function, GL_QUADS work everywhere, emulated as necessary.

• Modern OpenGL API

  Direct State Access (DSA) and Vertex Array Object (VAO), emulated as necessary.

• Open Source

  There is nothing behind the curtain. You can see what Regal is doing and change it if needed.

• Ease of Use

  Set breakpoints on OpenGL functions. Step into the code. Inspect state.

• Efficiency

  If it cannot be implemented efficiently in Regal, it is not universally supported. For example, tessellation support requires tessellation hardware.

Deployment

• Most code remains unchanged.
• Optionally #include <GL/Regal.h>
• Link with regal32.dll, libRegal.so or libRegal.dylib

From an application developer's perspective, Regal just looks like an OpenGL implementation. You link with it instead of your platform's OpenGL library or framework, and that's really all you have to do to use Regal. The rest of your code can remain unchanged.

Downloads

• github.com sources, ZIP snapshot.

July 30th 2013

• Windows x86 Debug | Windows x86 Release
• Windows AMD64 Debug | Windows AMD64 Release
• Mac Universal Debug | Mac Universal Release

Archives

• Archived Downloads

Features

Emulation

• Fixed function texturing, lighting and fog.

• Direct State Access extension

  http://www.opengl.org/registry/specs/EXT/direct_state_access.txt

• GL_EXT_debug_marker extension

  http://www.khronos.org/registry/gles/extensions/EXT/EXT_debug_marker.txt

• Fixed function and DSA emulation enabled by default, except when compatibility context with DSA extension detected.

• Build-time configuration:

  • REGAL_EMULATION -- Enable/disable the use of emulation
  • REGAL_FORCE_EMULATION -- Force the use of emulation, even for compatibility contexts with DSA

• Environment variable configuration:

  • REGAL_EMULATION -- Enable/disable the use of emulation
  • REGAL_FORCE_EMULATION -- Force the use of emulation, even for compatibility contexts with DSA

• Runime configuration via GL_REGAL_enable:

  • GL_EMULATION_REGAL -- glEnable/glDisable emulation

Note

Emulation is not supported in REGAL_WRANGLER=1 mode.

OpenGL error checking

• Disabled by default.
• Build-time configuration: REGAL_ERROR
• Environment variable configuration: REGAL_ERROR
• Runtime configuration via GL_REGAL_enable: GL_ERROR_REGAL

Note

OpenGL error checking is not supported in REGAL_WRANGLER=1 mode.

Logging

Regal supports detailed logging for development purposes.

• Error -- Fatal and non-fatal Regal runtime errors.
• Warning -- Non-fatal Regal warnings.
• Info -- Informational messages.
• App -- Application calls into Regal.
• Driver -- Regal calls into OpenGL.
• Internal -- Internal Regal calls.
• Http -- HTTP traffic logging.

Build-time configuration:

• REGAL_LOG_ERROR
• REGAL_LOG_WARNING
• REGAL_LOG_INFO
• REGAL_LOG_APP
• REGAL_LOG_DRIVER
• REGAL_LOG_INTERNAL
• REGAL_LOG_HTTP

• Debug mode: All logging supported with error, warning, info and http logging enabled.
• Release mode: Support for application, driver and internal logging disabled by default.

Environment variable configuration:

• REGAL_LOG_ERROR
• REGAL_LOG_WARNING
• REGAL_LOG_INFO
• REGAL_LOG_APP
• REGAL_LOG_DRIVER
• REGAL_LOG_INTERNAL
• REGAL_LOG_HTTP
• REGAL_LOG_API --- Application + Driver OpenGL logging
• REGAL_LOG_NONE --- enable or disable all logging

Environment variable lookup is globally disabled by defining REGAL_NO_GETENV at compile-time.

Runtime configuration via GL_REGAL_log extension: (glEnable/glDisable/glIsEnabled)

• GL_LOG_ERROR_REGAL
• GL_LOG_WARNING_REGAL
• GL_LOG_INFO_REGAL
• GL_LOG_APP_REGAL
• GL_LOG_DRIVER_REGAL
• GL_LOG_INTERNAL_REGAL
• GL_LOG_HTTP_REGAL

Other compile-time or runtime configuration of logging:

• REGAL_LOG --- enable or disable logging
• REGAL_LOG_FILE --- log to specified filename
• REGAL_LOG_MAX_LINES --- limit the number of lines of multi-line messages (shaders, etc)
• REGAL_LOG_JSON --- log in JSON mode
• REGAL_LOG_JSON_FILE --- JSON log to specified filename

Note

API logging is not supported in REGAL_WRANGLER=1 mode.

Multi-threading support

• Locking and per-thread contexts enabled by default.
• Per-thread context build-time configuration: REGAL_NO_TLS
• Locking build-time configuration: REGAL_THREAD_LOCKING
• Locking environment variable configuration: REGAL_THREAD_LOCKING

Spoofing OpenGL vendor, renderer, version and extension strings

Build-time configuration

• REGAL_GL_VENDOR
• REGAL_GL_RENDERER
• REGAL_GL_VERSION
• REGAL_GL_EXTENSIONS

Environment variable configuration:

• REGAL_GL_VENDOR
• REGAL_GL_RENDERER
• REGAL_GL_VERSION
• REGAL_GL_EXTENSIONS

Environment variable lookup is globally disabled by defining REGAL_NO_GETENV at compile-time.

Browser-based interface

• Enabled by default.
• REGAL_HTTP --- Build-time and environment variable enable/disable.
• REGAL_HTTP_PORT --- Port for HTTP connections (8080 by default)
• REGAL_HTTP_LOG_LIMIT --- Number of lines of logging buffered
• http://127.0.0.1:8080/log --- View log
• http://127.0.0.1:8080/glEnable?GL_LOG_APP_REGAL --- Enable/disable application logging
• http://127.0.0.1:8080/glEnable?GL_LOG_DRIVER_REGAL --- Enable/disable driver logging
• http://127.0.0.1:8080 --- State information

Note

Browser interface is not supported in REGAL_WRANGLER=1 mode.

Regal OpenGL extensions

• GL_REGAL_error_string for GLU-style GLenum to error string conversion.
• GL_REGAL_extension_query for GLEW-style extension checking.
• GL_REGAL_log for Regal logging configuration.
• GL_REGAL_enable for Regal feature configuration.

Regal API

• RegalSetErrorCallback --- Optionally set the per-context error callback function.
• RegalShareContext --- OpenGL contexts are shared.
• RegalMakeCurrent --- Set an OpenGL context as current for the thread.
• RegalDestroyContext --- Cleanup Regal context resources.

In Progress

• Light-weight loader-only "wrangler" mode along the lines of GLEW.
• Context sharing support
• glPushAttrib emulation

Planned Features

• NV_path_rendering emulation.
• GLSL to GLSL translation.
• ES 3.0 support
• Debug label.
• Debug output.
• Display list emulation.
• Web browser-based debugging tools.

Limitations

• Shared OpenGL contexts supported for single-threaded only.
• Limited GLSL language support.
• GL_QUADS only works in immediate mode or with DrawArrays for ES and core profiles.

Contact Information

• Discussion of Regal is primarily via the Issue Tracker currently.

Other Information

• Big Android BBQ 2013: Developing for Dedicated Android Gaming Systems (.pdf slides).
• #AltDevBlogADay blog: Bringing Regal OpenGL to Native Client.
• opengl.org forum thread: Introducing Regal.
• Slides - Regal for Software Development.

Platform Notes

Windows

Linux

• RedHat/Fedora recommended packages:

• 32-bit:

$ sudo yum install gcc-c++ zlib-devel libpng-devel libXmu-devel libXi-devel

• 64-bit

$ sudo yum install gcc-c++

$ sudo yum install zlib-devel.i686 libpng-devel.i686

$ sudo yum install zlib-devel.x86_64 libpng-devel.x86_64

$ sudo yum install libXmu-devel libXi-devel

• Ubuntu/Debian/Mint recommended packages:

$ apt-get install libxmu-dev libxi-dev

• Use GNU make with Makefile

$ make -f Makefile CCACHE=ccache STRIP=

• Set LD_LIBRARY_PATH

$ export LD_LIBRARY_PATH=`pwd`/lib/linux

• Run the dreamtorus example

$ REGAL_FORCE_EMULATION=1; bin/linux/dreamtorus

$ REGAL_FORCE_EMULATION=0; bin/linux/dreamtorus

$ REGAL_LOG_DRIVER=1; bin/linux/dreamtorus

OS X

Android

iOS

PPAPI and NaCl

• NACL_SDK_ROOT needs to be set
• NACL_LIBC=newlib is the default, specify glibc or pnacl as alternatives

Questions and Answers

STL, Standard C++ Library, Boost

• For and against STL.
• For and against Boost.

Alternatives for OpenGL Loading

• GLEW.
• OpenGL Loader Generator.

Related Efforts

• Mesa3D mail thread: Mesa as part of OpenGL-on-OpenGL ES 2.0
• glshim, Pandora forum thread.
• Runtime OpenGL to OpenGL ES translator: glesport, OpenGL ES for Maemo.

License and Credits

Regal code, API database and generators are BSD licensed.

Copyright (c) 2011-2014 NVIDIA Corporation
Copyright (c) 2012-2015 Google Inc.
Copyright (c) 2012-2015 Nigel Stewart
Copyright (c) 2012-2014 Scott Nations
Copyright (c) 2011-2013 Cass Everitt
Copyright (c) 2012 Mathias Schott
All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

  Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

  Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
OF THE POSSIBILITY OF SUCH DAMAGE.

Boost is licensed under Boost Software License.

zlib by Jean-loup Gailly and Mark Adler is licensed under zLib License.

libpng by Glenn Randers-Pehrson et. al. is licensed under libpng license.

lookup3 by Bob Jenkins is public domain.

GLEW is licensed under BSD and MIT License.

GLU is licensed under SGI FREE SOFTWARE LICENSE B.

GLUT license:

/* Copyright (c) Mark J. Kilgard, 1994, 1995, 1996, 1998. */

/* This program is freely distributable without licensing fees  and is
   provided without guarantee or warrantee expressed or  implied. This
   program is -not- in the public domain. */

Dreamtorus example program is public domain.