#File: sdlglwrappergen.py

#This list gets appended by AddFunc.
funcs = []

#The name should be a string (the function name, e.g. "glColor3f").
#The params should be a list of pairs.
#The first element of each pair should be the string for the type (e.g. "GLfloat").
#The second element of each pair should be the string for the arg name (e.g. "r").
def AddFunc(name, params):
    funcs.append((name,params))

def Helper_PrintTypedef(hf, name, params):
    hf.write('    typedef void (APIENTRY * ' + name + '_Func)(')
    i = 0
    for (type_name, arg) in params:
        i += 1
        hf.write(type_name)
        if i != len(params):
            hf.write(', ')
    hf.write(');\n')

def Helper_PrintPtrDef(hf, name):
    hf.write('    ' + name + '_Func ' + name + '_ptr;\n')

def Helper_PrintWrapperFuncDec(hf, name, params):
    hf.write('    void ' + name + '(')
    i = 0
    for (type_name, arg) in params:
        i += 1
        hf.write(type_name)
        hf.write(' ')
        hf.write(arg)
        if i != len(params):
            hf.write(', ')
    hf.write(');\n')

def Helper_PrintSetPtrToNull(cf, name):
    cf.write('    ' + name + '_ptr = 0;\n')

def Helper_PrintFuncPtrGetter(cf, name):
    cf.write('    ' + name + '_ptr = (' + name + '_Func) ')
    cf.write('GetProcAddrHelper(\"' + name + '\");\n')

def Helper_PrintWrapperFuncDef(cf, name, params):
    cf.write('\n')
    cf.write('void OpenGLWrapper::' + name + '(')
    i = 0
    for (type_name, arg) in params:
        i += 1
        cf.write(type_name)
        cf.write(' ')
        cf.write(arg)
        if i != len(params):
            cf.write(', ')
    cf.write(') {\n')
    cf.write('    ' + name + '_ptr(')
    i = 0
    for (type_name, arg) in params:
        i += 1
        cf.write(arg)
        if i != len(params):
            cf.write(', ')
    cf.write(');\n')
    cf.write('}\n')

#Prints to output the contents of "GLWrapper.h".
def GenWrapper():
    #hf stands for header file.
    #cf stands for source file.
    hf = open('OpenGLWrapper.h', 'w')
    cf = open('OpenGLWrapper.cpp', 'w')
    #Generating the header file.
    hf.write('//File: OpenGLWrapper.h\n')
    hf.write('//This C++ header was autogenerated\n')
    hf.write('//using a python script (by Dan Hathaway).\n')
    hf.write('\n')
    hf.write('#ifndef OpenGLWrapper_h_\n')
    hf.write('#define OpenGLWrapper_h_\n')
    hf.write('\n')
    hf.write('//Replace the next include with \"gl.h\" or whatever.\n')
    hf.write('//This is only needed for the type definitions,\n')
    hf.write('//so if you want you can just typedef them yourself.\n')
    hf.write('#include \"OpenGLInclude.h\"\n')
    hf.write('\n')
    hf.write('//-----------------------------------------------\n')
    hf.write('//                                               \n')
    hf.write('//                OPEN GL WRAPPER                \n')
    hf.write('//                                               \n')
    hf.write('//-----------------------------------------------\n')
    hf.write('\n')
    hf.write('//The singleton instance of this class should\n')
    hf.write('//be used to make OpenGL calls.  When the singleton\n')
    hf.write('//is constructed, SDL_GL_GetProcAddress will be called,\n')
    hf.write('//so SDL must be initialzied before this.\n')
    hf.write('\n')
    hf.write('class OpenGLWrapper {\n')
    hf.write('private:\n')
    hf.write('    //Typedefs.\n')
    for (name, params) in funcs:
        Helper_PrintTypedef(hf, name, params)
    hf.write('\n')
    hf.write('    //The singleton.\n')
    hf.write('    static class GLWrapper * singleton;\n')
    hf.write('\n')
    hf.write('    //These should all be initially set to 0.\n')
    for (name, params) in funcs:
        Helper_PrintPtrDef(hf, name)
    hf.write('\n')
    hf.write('    void Initialize();')
    hf.write('\n')
    hf.write('    void * GetProcAddrHelper(const char * name);\n')
    hf.write('\n')
    hf.write('    //Can only construct by getting the singleton.\n')
    hf.write('    OpenGLWrapper();\n')
    hf.write('    ~OpenGLWrapper();\n')
    hf.write('\n')
    hf.write('public:\n')
    hf.write('    //The first call to this will\n')
    hf.write('    //instantiate the singleton,\n')
    hf.write('    //so SDL must already be initialized\n')
    hf.write('    //when this happens.\n')
    hf.write('    static OpenGLWrapper & Inst();\n')
    hf.write('\n')
    hf.write('    //Some OpenGL functions.\n')
    #hf.write('    //If you wish they were inlined,\n')
    #hf.write('    //then cut and paste the function definitions\n')
    #hf.write('    //from the .cpp file to here.\n')
    for (name, params) in funcs:
        Helper_PrintWrapperFuncDec(hf, name, params)
    hf.write('};\n')
    hf.write('\n')
    hf.write('#endif\n')
    #Generating the source file.
    cf.write('//File: OpenGLWrapper.cpp\n')
    cf.write('\n')
    cf.write('#include "OpenGLWrapper.h"\n')
    cf.write('\n')
    cf.write('#include <SDL/SDL.h> //For SDL_GL_GetProcAddress.\n')
    cf.write('\n')
    cf.write('#include <cstdlib> //For exit.\n')
    cf.write('#include <iostream> //For cout.\n')
    cf.write('using std::cout;\n')
    cf.write('\n')
    cf.write('OpenGLWrapper * OpenGLWrapper::singleton = 0;\n')
    cf.write('\n')
    cf.write('OpenGLWrapper & OpenGLWrapper::Inst() {\n')
    cf.write('    if( singleton == 0 ) {\n')
    cf.write('        singleton = new GLWrapper;\n')
    cf.write('    }\n')
    cf.write('    return *singleton;\n')
    cf.write('}\n')
    cf.write('\n')
    cf.write('OpenGLWrapper::OpenGLWrapper() {\n')
    cf.write('    //Better safe than sorry.\n')
    for (name, params) in funcs:
        Helper_PrintSetPtrToNull(cf, name)
    cf.write('\n')
    cf.write('    Initialize();\n')
    cf.write('}\n')
    cf.write('\n')
    cf.write('OpenGLWrapper::~OpenGLWrapper() {\n')
    cf.write('    //Nothing to do.\n')
    cf.write('}\n')
    cf.write('\n')
    cf.write('void * OpenGLWrapper::GetProcAddrHelper(\n')
    cf.write('    const char * name)\n')
    cf.write('{\n')
    cf.write('    //Uncomment the next line if you want.\n')
    cf.write('    //cout << "Calling SDL_GL_GetProcAddress(\"" << name << "\")\\n";\n')
    cf.write('    void * function_ptr = 0;\n')
    cf.write('    function_ptr = SDL_GL_GetProcAddress(name);\n')
    cf.write('    if( function_ptr == 0 ) {\n')
    cf.write('        cout << "*** Error in GLWrapper::GetProcAddressHelper:\\n"\n')
    cf.write('            << "cannot get function pointer: " << name << "\\n"\n')
    cf.write('            << "from SDL_GL_GetProcAddress\\n";\n')
    cf.write('        PoliteExit();\n')
    cf.write('    }\n')
    cf.write('    return function_ptr;\n')
    cf.write('}\n')
    cf.write('\n')
    cf.write('void GLWrapper::Initialize() {\n')
    for (name, params) in funcs:
        Helper_PrintFuncPtrGetter(cf, name)
    cf.write('}\n')
    for (name, params) in funcs:
        Helper_PrintWrapperFuncDef(cf, name, params)

#HEY YOU HUMAN.
#Modify these and/or add your own:
AddFunc('glEnd',        [])
AddFunc('glTranslated', [('GLdouble','x'),('GLdouble','y'),('GLdouble','z')])
AddFunc('glColor3f',    [('GLfloat','r'),('GLfloat','g'),('GLfloat','b')])

#Generating the .h and .cpp files.
GenWrapper();