glbindify

glbindify

glbindify is a command line tool that generates C bindings for OpenGL, WGL, and GLX. The generated bindings can then be included in your projects, eliminating the need to link to a seperate loader library. The bindings are generated using XML API specifications mainained by khronos so only these XML files need to be updated to support new GL versions or extensions.

It supports generating bindings for core profile contexts only which substantially reduces the size of the bindings. Also the generated header file only exposes functions and enums for API versions and extensions you select at compile time, ensuring that your application does not accidentally aquire unwanted dependencies.

Command line usage

To generate bindings just specify the API name to glbindify where the API name is one of gl, wgl, or glx. The tool will generate a source file and header file for the API in the current directory with the named glb-<api>.c and glb-<api>.h.

Example: Generate C bindings for OpenGL core profile contexts

glbindify -a gl

Using the bindings

After you have created your OpenGL context and made it current you must call

bool glb_<api>_init(int major_version, int minor_version)

where <api> is one of glcore, wgl, or glx. If all functions for the requested version, excluding extensions, were found glb_<api>_init() will return true. Since glbindify mangles the GL function names with '#define' macros you must avoid including system OpenGL headers in files that also include the bindings.

Example:

#include "glb-glcore.h"
...
if (!glb_glcore_init(3, 3))
    exit(-1);
...
glDrawArrays(...);

Targeting specific versions

By default the generated header file will only expose functions and enums for the minimum version supported by glbindify. For GL the minimum version is 3.2 core profile, for GLX it is 1.4, and for WGL it is 1.0. To access functionality for later versions you must define a macro GLB_<API>_VERSION as an integer (major_version * 10) + minor_version where <API> is the name of the API in all caps.

Extensions

After initializing the bindings you may determine if an extension was successully loaded by checking its corresponding support flag. The support flags are named GLB_<extension name>. An extension support flag will be set to true if it's name was found in the driver's extension string and all functions for the extension were located. An extension's specific functions and enum values will only be exposed if the macro GLB_ENABLE_<extension name> is defined.

Example: Checking for the GL_ARB_texture_storage extension

#define GLB_GL_VERSION 33
#define GLB_ENABLE_GL_ARB_texture_storage 1
#include "glb-glcore.h"
...
if (GLB_GL_ARB_texture_storage) {
    glTexStorage3D(...);
} else {
    ...
}

Building

glbindify requires only a ANSI C++ compiler. If gperf is available glbindify will search generate a perfect hash map for extension checking at initialization time. On any UNIX-like system it can be built and installed with it's autotools build system:

./autogen.sh
./configure <options>
make
make install

It can also be built without the build system just by compiling the sources with default options. For example:

g++ -ansi glbindify.cpp tinyxml2.cpp -o glbindify