/***********************************************************************
 * Copyright 2011-2012 Computer Graphics Group RWTH Aachen University. *
 * All rights reserved.                                                *
 * Distributed under the terms of the MIT License (see LICENSE.TXT).   *
 **********************************************************************/

#ifndef ACGL_OPENGL_GL_HH
#define ACGL_OPENGL_GL_HH

/*
 * This simple OpenGL wrapper is used to include OpenGL (and if needed GLEW)
 * on different platforms.
 *
 * While these includes are located in a subdirectory of GL/ on most systems,
 * Apple hides them on different locations.
 *
 *
 * This wrapper can get configured with external defines:
 * ACGL_OPENGL_PROFILE_CORE      : if defined: if possible include/load only core OpenGL functions
 *                                 if not defined: support for CORE and deprecated functions
 *                                 (NOTE: the OpenGL context itself is not created by ACGL!)
 * ACGL_OPENGLES_VERSION_20      : if defined: OpenGL ES 2.0
 * ACGL_OPENGLES_VERSION_30      : if defined: OpenGL ES 3.0
 * ACGL_OPENGL_VERSION_41        : (or other versions): minimal OpenGL version that can be assumed to be present.
 *                                 The app can't run on older contexts and will probably terminate at startup.
 *                                 Set this to a low version and it will run on lost machines
 *                                 Set this to a high version and less run-time checks have to be performed to
 *                                 work around missing features (like querying extensions etc).
 * ACGL_OPENGL_INCLUDE_LATEST_GL : If this is set and GL function loading is done with the internal loader, all
 *                                 functions of the latest GL version are loaded (if available) and the header
 *                                 of the latest version gets included. ACGL however will only assume the version
 *                                 set by ACGL_OPENGL_VERSION_XY to be present.
 *
 * ACGL_USE_GLEW                 : if this is set, GLEW gets used to load the GL functions,
 *                                 otherwise an internal GL loader based on glLoadGen gets used on desktop systems.
 *
 * Note: If nothing is defined, core 3.2 gets defined but all functions are loaded.
 *       If *just* ACGL_OPENGL_INCLUDE_LATEST_GL is defined, the latest GL version gets defined *and* loaded
 *       (full/compatibility profile).
 */

// Android autodetection:
#ifdef __ANDROID__
#   define ACGL_OPENGL_ES
#   define PLATFORM_ANDROID
#endif

// If we're compiling for an Apple system we need this to distinquish between Mac and iOS:
#ifdef __APPLE__
#   include <TargetConditionals.h>
#endif

#if (defined(TARGET_OS_IPHONE) || defined(TARGET_IPHONE_SIMULATOR))
#   if (TARGET_OS_IPHONE == 1)
#       define PLATFORM_IOS
#       define ACGL_OPENGL_ES
#   endif
#endif

// To compare the OpenGL version number we define a new ACGL_OPENGL_VERSION XY define here
// analog to ACGL_OPENGL_VERSION_XY

// OpenGL ES 2.0 is the default for embedded:
#ifdef ACGL_OPENGL_ES
#  if   defined (ACGL_OPENGLES_VERSION_30)
#       define   ACGL_OPENGLES_VERSION 30
#       define   ACGL_OPENGL_VERSION    0
#  else 
#       define ACGL_OPENGLES_VERSION_20
#       define ACGL_OPENGLES_VERSION 20
#       define ACGL_OPENGL_VERSION    0
#  endif
#else
    // Desktop:
    #if   defined (ACGL_OPENGL_VERSION_21)
    #     define   ACGL_OPENGL_VERSION 21
    #elif defined (ACGL_OPENGL_VERSION_30)
    #     define   ACGL_OPENGL_VERSION 30
    #elif defined (ACGL_OPENGL_VERSION_31)
    #     define   ACGL_OPENGL_VERSION 31
    #elif defined (ACGL_OPENGL_VERSION_32)
    #     define   ACGL_OPENGL_VERSION 32
    #elif defined (ACGL_OPENGL_VERSION_33)
    #     define   ACGL_OPENGL_VERSION 33
    #elif defined (ACGL_OPENGL_VERSION_40)
    #     define   ACGL_OPENGL_VERSION 40
    #elif defined (ACGL_OPENGL_VERSION_41)
    #     define   ACGL_OPENGL_VERSION 41
    #elif defined (ACGL_OPENGL_VERSION_42)
    #     define   ACGL_OPENGL_VERSION 42
    #elif defined (ACGL_OPENGL_VERSION_43)
    #     define   ACGL_OPENGL_VERSION 43
    #elif defined (ACGL_OPENGL_VERSION_44)
    #     define   ACGL_OPENGL_VERSION 44
    #else
	#if defined (ACGL_OPENGL_INCLUDE_LATEST_GL)
        #define ACGL_OPENGL_VERSION_44
        #define ACGL_OPENGL_VERSION 44
	    #define ACGL_OPENGL_PROFILE_FULL
	#else
	    // fallback:
	    #warning "NO ACGL_OPENGL_VERSION_XY SET! Default to 3.2 core (but load all available functions)"
	    // *we* only assume OpenGL 3.2 core...
	    #define ACGL_OPENGL_VERSION_32
	    #define ACGL_OPENGL_VERSION 32
	    #define ACGL_OPENGL_PROFILE_CORE
	    // ... but include the latest header and try to load all function in case the app needs more:
	    // (only if the internal loader gets used, but GLEW will also try to load everything)
	    #define ACGL_OPENGL_INCLUDE_LATEST_GL
	#endif // latest GL
    #endif // version checks
#endif // OpenGL ES


#if (ACGL_OPENGL_VERSION < 32) && defined(ACGL_OPENGL_PROFILE_CORE)
    #warning "OpenGL prior to 3.2 did not have core or compatibility profiles"
    #undef ACGL_OPENGL_PROFILE_CORE
#endif

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//  Include the right headers with the OpenGL functions and defines:
//
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void CHECKGLERROR();

#ifdef ACGL_OPENGL_ES
  // ES does not know 64bit ints but we need them for the Buffer class:
  #include <stdint.h>
  typedef int64_t GLint64;
  
    #if (PLATFORM_IOS)
        //iOS:
        #if defined (ACGL_OPENGLES_VERSION_20)
            #import <OpenGLES/ES1/gl.h>
            #import <OpenGLES/ES1/glext.h>
            #import <OpenGLES/ES2/gl.h>
            #import <OpenGLES/ES2/glext.h>
        #else
            #error "location of ES 3 headers not known"
        #endif
    #elif defined (PLATFORM_ANDROID)
        // Android:
        #if defined (ACGL_OPENGLES_VERSION_20)
            //#include <GLES/gl.h>
            //#include <GLES/glext.h>
            #include <GLES2/gl2.h>
            #include <GLES2/gl2ext.h>
        #else
            #include <GLES3/gl3.h>
            #include <GLES3/gl3ext.h>
        #endif
    #else
        #error "UNKNOWN mobile plattform! Don't know what to include!"
    #endif
#else // ACGL_OPENGL_ES
    // desktop:
    #ifndef __glew_h__
        // if glew was already included, don't include anything else
        // not the recommended way to do it but possible
        #if (defined(__APPLE__) || defined(MACOSX)) && defined(ACGL_OPENGL_PROFILE_FULL)
            #if ACGL_OPENGL_VERSION > 21
                #warning "On MacOS X only core profile is supported for OpenGL >= 3.2"
                #undef ACGL_OPENGL_PROFILE_FULL
                #define ACGL_OPENGL_PROFILE_CORE
            #endif
        #endif
        #ifdef ACGL_USE_GLEW
            #define ACGL_EXTENSION_LOADER_GLEW
            #if defined(__APPLE__) || defined(MACOSX)
                #include <OpenGL/glew.h>
            #else
                #include <GL/glew.h>
            #endif
        #else
            // use the internal loader:
            #define ACGL_EXTENSION_LOADER_GLLOADGEN
            #if defined(__gl_h_) || defined(__GL_H__) || defined(__glext_h_) || defined(__GLEXT_H_) || defined(__gl_ATI_h_) || defined(__gl3_h_)
            #error ACGL/GL.hh has to be the first OpenGL related file to include!
            #endif

            //
            // Include the right header which has just what is needed to catch compatibility problems at compiletime.
            // The selection could also be done with some preprocessor magic but it confuses most IDEs.
            //
            #ifdef ACGL_OPENGL_PROFILE_CORE
                #if defined (ACGL_OPENGL_VERSION_32)
                    #include <ACGL/OpenGL/glloaders/gl_core_32.hh>
                #elif defined (ACGL_OPENGL_VERSION_33)
                    #include <ACGL/OpenGL/glloaders/gl_core_33.hh>
                #elif defined (ACGL_OPENGL_VERSION_40)
                    #include <ACGL/OpenGL/glloaders/gl_core_40.hh>
                #elif defined (ACGL_OPENGL_VERSION_41)
                    #include <ACGL/OpenGL/glloaders/gl_core_41.hh>
                #elif defined (ACGL_OPENGL_VERSION_42)
                    #include <ACGL/OpenGL/glloaders/gl_core_42.hh>
                #elif defined (ACGL_OPENGL_VERSION_43)
                    #include <ACGL/OpenGL/glloaders/gl_core_43.hh>
                #elif defined (ACGL_OPENGL_VERSION_44)
                    #include <ACGL/OpenGL/glloaders/gl_core_44.hh>
                #endif
            #else
                // compatibility profile:
                #if defined (ACGL_OPENGL_VERSION_21)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_21.hh>
                #elif defined (ACGL_OPENGL_VERSION_30)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_30.hh>
                #elif defined (ACGL_OPENGL_VERSION_31)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_31.hh>
                #elif defined (ACGL_OPENGL_VERSION_32)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_32.hh>
                #elif defined (ACGL_OPENGL_VERSION_33)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_33.hh>
                #elif defined (ACGL_OPENGL_VERSION_40)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_40.hh>
                #elif defined (ACGL_OPENGL_VERSION_41)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_41.hh>
                #elif defined (ACGL_OPENGL_VERSION_42)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_42.hh>
                #elif defined (ACGL_OPENGL_VERSION_43)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_43.hh>
                #elif defined (ACGL_OPENGL_VERSION_44)
                    #include <ACGL/OpenGL/glloaders/gl_compatibility_44.hh>
                #endif
            #endif // ACGL_OPENGL_PROFILE_CORE
            // prevent other GL headers from getting included and redefine GL:
            #define __gl3_h_
        #endif // ACGL_USE_GLEW
    #else
        #define ACGL_USE_GLEW
        #define ACGL_EXTENSION_LOADER_GLEW
    #endif // __GLEW__
#endif // ACGL_OPENGL_ES

#endif // ACGL_OPENGL_GL_HH