# GLExtGen:## GLExtGen is a Ruby script which is capable of extracting OpenGL extension# data from header files and generate files for inclusion in OpenGL projects.## GLExtGen works using a front-end and a back-end. The front-end is responsible# for analyzing the header files and building an intermediate representation.# The backend is then responsible for writing out that information in a way that# the target language can understand it. This design allows different backends# (say for PASCAL/Delphi) to be generated without having to rewrite lots of# code. Unfortunately, this separation is not as good as it could be. For example,# GLBackEnd is really not designed to be derived from. It should be more of an# interface, than an actual implementation. Nevertheless, it works quite well for# C++. If you want something else, I suggest just changing the code in GLBackEnd# perform error checking on config parametersbeginif $target != "win32" && $target != "x"	raise "Incorrect target specification"endif $path[-1] != '/'[0] && $path[-1] != '\\'[0]	$path += '/'	print "WARNING: No trailing slash in path ... adjusting\n"	print "WARNING: New path is '", $path, "'\n"endrequire 'script/glextension.rb'require 'script/glfrontend.rb'require 'script/glmunger.rb'require 'script/glbackend.rb'# here we choose the classes we will usefrontEndClass 	= GLExtGen::GLFrontEndmungerClass		= GLExtGen::GLMungerbackEndClass 	= GLExtGen::GLBackEnd# we will use these hash tables to hold string => GLExtension pairsglExtensionHash = {}wglExtensionHash = {}glXExtensionHash = {}# create our front endfrontEnd = frontEndClass.new# queue up some jobs to scanfrontEnd.addFile($path+"glext.h", '(#ifndef) (GL_\w+)', '(.+) (gl\w+)', glExtensionHash)if $target == "win32"	frontEnd.addFile($path+"wglext.h", '(#ifndef) (WGL_\w+)', '(.+) (wgl\w+)', wglExtensionHash)endif $target == "x"	frontEnd.addFile($path+"glxext.h", '(#ifndef) (GLX_\w+)', '(.+) (glX\w+)', glXExtensionHash)end# let's work itfrontEnd.scanAll# now, for the MS-Windows world, this is fine, but other OpenGL implementations (such as Mesa)# already define some of the symbols, as their GL/gl.h implements version 1.2 and not 1.1 (as# the Windows header). So, what we do is, we analyze the regular gl-header file.	extensionExp = Regexp.new('(#ifndef) (GL_\w+)')	versionExp = Regexp.new('(#define) (GL_VERSION\w+)')	glNativeSupportArray = []	print "\nSearching for native extensions in '"+$path+"gl.h\n"	File.open($path+"gl.h").each { |line|		if md = extensionExp.match(line)			glNativeSupportArray.push(md[2]);			print "Found extension: " + md[2] + "\n"		elsif md = versionExp.match(line)			glNativeSupportArray.push(md[2]);			print "Found version: " + md[2] + "\n"		end	}	# before we pass this data to the backend we get a chance to transform it.	munger = mungerClass.new(glNativeSupportArray)	munger.processGL(glExtensionHash)	munger.processWGL(wglExtensionHash)	munger.processGLX(glXExtensionHash)	# at this point the extension hashes contain valid data (let's cross our fingers)	# now we have done all our processing and sort the extensions	glExtensionArray	= glExtensionHash.sort	wglExtensionArray	= wglExtensionHash.sort	glXExtensionArray	= glXExtensionHash.sort	# create back end	backEnd = backEndClass.new        # glExtensionArray.each { |item|        # 	item[1].functionList.each { |func| 	#                print "debug output: " + func + "\n"        # 	}        # }	# now, we just hand our extension arrays over to the backend	#	# Note: we are also passing in the frontEnd, because it should contain information	#		on how to 'procize' a function (generate function pointer typedef given a	#		function name)	backEnd.generate(frontEnd, glExtensionArray, wglExtensionArray, glXExtensionArray)rescue StandardError => bang	print "ERROR: ", bang, "\n"end