/*

  Simple DirectMedia Layer

  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied

  warranty.  In no event will the authors be held liable for any damages

  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,

  including commercial applications, and to alter it and redistribute it

  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not

     claim that you wrote the original software. If you use this software

     in a product, an acknowledgment in the product documentation would be

     appreciated but is not required.

  2. Altered source versions must be plainly marked as such, and must not be

     misrepresented as being the original software.

  3. This notice may not be removed or altered from any source distribution.

*/

#include "SDL_config.h"

#if SDL_VIDEO_DRIVER_X11

#include "SDL_x11video.h"

#include "SDL_assert.h"

/* GLX implementation of SDL OpenGL support */

#if SDL_VIDEO_OPENGL_GLX

#include "SDL_loadso.h"

#if defined(__IRIX__)

/* IRIX doesn't have a GL library versioning system */

#define DEFAULT_OPENGL	"libGL.so"

#elif defined(__MACOSX__)

#define DEFAULT_OPENGL	"/usr/X11R6/lib/libGL.1.dylib"

#elif defined(__QNXNTO__)

#define DEFAULT_OPENGL	"libGL.so.3"

#else

#define DEFAULT_OPENGL	"libGL.so.1"

#endif

#ifndef GLX_NONE_EXT

#define GLX_NONE_EXT                       0x8000

#endif

#ifndef GLX_ARB_multisample

#define GLX_ARB_multisample

#define GLX_SAMPLE_BUFFERS_ARB             100000

#define GLX_SAMPLES_ARB                    100001

#endif

#ifndef GLX_EXT_visual_rating

#define GLX_EXT_visual_rating

#define GLX_VISUAL_CAVEAT_EXT              0x20

#define GLX_NONE_EXT                       0x8000

#define GLX_SLOW_VISUAL_EXT                0x8001

#define GLX_NON_CONFORMANT_VISUAL_EXT      0x800D

#endif

#ifndef GLX_ARB_create_context

#define GLX_ARB_create_context

#define GLX_CONTEXT_MAJOR_VERSION_ARB      0x2091

#define GLX_CONTEXT_MINOR_VERSION_ARB      0x2092

#define GLX_CONTEXT_FLAGS_ARB              0x2094

#define GLX_CONTEXT_DEBUG_BIT_ARB          0x0001

#define GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB 0x0002

/* Typedef for the GL 3.0 context creation function */

typedef GLXContext(*PFNGLXCREATECONTEXTATTRIBSARBPROC) (Display * dpy,

                                                        GLXFBConfig config,

                                                        GLXContext

                                                        share_context,

                                                        Bool direct,

                                                        const int

                                                        *attrib_list);

#endif

#define OPENGL_REQUIRES_DLOPEN

#if defined(OPENGL_REQUIRES_DLOPEN) && defined(SDL_LOADSO_DLOPEN)

#include <dlfcn.h>

#define GL_LoadObject(X)	dlopen(X, (RTLD_NOW|RTLD_GLOBAL))

#define GL_LoadFunction		dlsym

#define GL_UnloadObject		dlclose

#else

#define GL_LoadObject	SDL_LoadObject

#define GL_LoadFunction	SDL_LoadFunction

#define GL_UnloadObject	SDL_UnloadObject

#endif

static void X11_GL_InitExtensions(_THIS);

int

X11_GL_LoadLibrary(_THIS, const char *path)

{

    void *handle;

    /* Load the OpenGL library */

    if (path == NULL) {

        path = SDL_getenv("SDL_OPENGL_LIBRARY");

    }

    if (path == NULL) {

        path = DEFAULT_OPENGL;

    }

    _this->gl_config.dll_handle = GL_LoadObject(path);

    if (!_this->gl_config.dll_handle) {

#if defined(OPENGL_REQUIRES_DLOPEN) && defined(SDL_LOADSO_DLOPEN)

        SDL_SetError("Failed loading %s: %s", path, dlerror());

#endif

        return -1;

    }

    SDL_strlcpy(_this->gl_config.driver_path, path,

                SDL_arraysize(_this->gl_config.driver_path));

    /* Allocate OpenGL memory */

    _this->gl_data =

        (struct SDL_GLDriverData *) SDL_calloc(1,

                                               sizeof(struct

                                                      SDL_GLDriverData));

    if (!_this->gl_data) {

        SDL_OutOfMemory();

        return -1;

    }

    /* Load function pointers */

    handle = _this->gl_config.dll_handle;

    _this->gl_data->glXGetProcAddress =

        (void *(*)(const GLubyte *))

            GL_LoadFunction(handle, "glXGetProcAddressARB");

    _this->gl_data->glXChooseVisual =

        (XVisualInfo * (*)(Display *, int, int *))

            X11_GL_GetProcAddress(_this, "glXChooseVisual");

    _this->gl_data->glXCreateContext =

        (GLXContext(*)(Display *, XVisualInfo *, GLXContext, int))

            X11_GL_GetProcAddress(_this, "glXCreateContext");

    _this->gl_data->glXDestroyContext =

        (void (*)(Display *, GLXContext))

            X11_GL_GetProcAddress(_this, "glXDestroyContext");

    _this->gl_data->glXMakeCurrent =

        (int (*)(Display *, GLXDrawable, GLXContext))

            X11_GL_GetProcAddress(_this, "glXMakeCurrent");

    _this->gl_data->glXSwapBuffers =

        (void (*)(Display *, GLXDrawable))

            X11_GL_GetProcAddress(_this, "glXSwapBuffers");

    _this->gl_data->glXQueryDrawable =

        (void (*)(Display*,GLXDrawable,int,unsigned int*))

            X11_GL_GetProcAddress(_this, "glXQueryDrawable");

    if (!_this->gl_data->glXChooseVisual ||

        !_this->gl_data->glXCreateContext ||

        !_this->gl_data->glXDestroyContext ||

        !_this->gl_data->glXMakeCurrent ||

        !_this->gl_data->glXSwapBuffers) {

        SDL_SetError("Could not retrieve OpenGL functions");

        return -1;

    }

    /* Initialize extensions */

    X11_GL_InitExtensions(_this);

    return 0;

}

void *

X11_GL_GetProcAddress(_THIS, const char *proc)

{

    if (_this->gl_data->glXGetProcAddress) {

        return _this->gl_data->glXGetProcAddress((const GLubyte *) proc);

    }

    return GL_LoadFunction(_this->gl_config.dll_handle, proc);

}

void

X11_GL_UnloadLibrary(_THIS)

{

    /* Don't actually unload the library, since it may have registered

     * X11 shutdown hooks, per the notes at:

     * http://dri.sourceforge.net/doc/DRIuserguide.html

     */

#if 0

    GL_UnloadObject(_this->gl_config.dll_handle);

    _this->gl_config.dll_handle = NULL;

#endif

    /* Free OpenGL memory */

    if (_this->gl_data) {

        SDL_free(_this->gl_data);

        _this->gl_data = NULL;

    }

}

static SDL_bool

HasExtension(const char *extension, const char *extensions)

{

    const char *start;

    const char *where, *terminator;

    /* Extension names should not have spaces. */

    where = SDL_strchr(extension, ' ');

    if (where || *extension == '\0')

        return SDL_FALSE;

    if (!extensions)

        return SDL_FALSE;

    /* It takes a bit of care to be fool-proof about parsing the

     * OpenGL extensions string. Don't be fooled by sub-strings,

     * etc. */

    start = extensions;

    for (;;) {

        where = SDL_strstr(start, extension);

        if (!where)

            break;

        terminator = where + SDL_strlen(extension);

        if (where == start || *(where - 1) == ' ')

            if (*terminator == ' ' || *terminator == '\0')

                return SDL_TRUE;

        start = terminator;

    }

    return SDL_FALSE;

}

static void

X11_GL_InitExtensions(_THIS)

{

    Display *display = ((SDL_VideoData *) _this->driverdata)->display;

    int screen = DefaultScreen(display);

    XVisualInfo *vinfo;

    XSetWindowAttributes xattr;

    Window w;

    GLXContext context;

    const char *(*glXQueryExtensionsStringFunc) (Display *, int);

    const char *extensions;

    vinfo = X11_GL_GetVisual(_this, display, screen);

    if (!vinfo) {

        return;

    }

    xattr.background_pixel = 0;

    xattr.border_pixel = 0;

    xattr.colormap =

        XCreateColormap(display, RootWindow(display, screen), vinfo->visual,

                        AllocNone);

    w = XCreateWindow(display, RootWindow(display, screen), 0, 0, 32, 32, 0,

                      vinfo->depth, InputOutput, vinfo->visual,

                      (CWBackPixel | CWBorderPixel | CWColormap), &xattr);

    context = _this->gl_data->glXCreateContext(display, vinfo, NULL, True);

    if (context) {

        _this->gl_data->glXMakeCurrent(display, w, context);

    }

    XFree(vinfo);

    glXQueryExtensionsStringFunc =

        (const char *(*)(Display *, int)) X11_GL_GetProcAddress(_this,

                                                                "glXQueryExtensionsString");

    if (glXQueryExtensionsStringFunc) {

        extensions = glXQueryExtensionsStringFunc(display, screen);

    } else {

        extensions = NULL;

    }

    /* Check for GLX_EXT_swap_control */

    if (HasExtension("GLX_EXT_swap_control", extensions)) {

        _this->gl_data->glXSwapIntervalEXT =

            (int (*)(Display*,GLXDrawable,int))

                X11_GL_GetProcAddress(_this, "glXSwapIntervalEXT");

    }

    /* Check for GLX_MESA_swap_control */

    if (HasExtension("GLX_MESA_swap_control", extensions)) {

        _this->gl_data->glXSwapIntervalMESA =

            (int(*)(int)) X11_GL_GetProcAddress(_this, "glXSwapIntervalMESA");

        _this->gl_data->glXGetSwapIntervalMESA =

            (int(*)(void)) X11_GL_GetProcAddress(_this,

                                                   "glXGetSwapIntervalMESA");

    }

    /* Check for GLX_SGI_swap_control */

    if (HasExtension("GLX_SGI_swap_control", extensions)) {

        _this->gl_data->glXSwapIntervalSGI =

            (int (*)(int)) X11_GL_GetProcAddress(_this, "glXSwapIntervalSGI");

    }

    /* Check for GLX_EXT_visual_rating */

    if (HasExtension("GLX_EXT_visual_rating", extensions)) {

        _this->gl_data->HAS_GLX_EXT_visual_rating = SDL_TRUE;

    }

    if (context) {

        _this->gl_data->glXMakeCurrent(display, None, NULL);

        _this->gl_data->glXDestroyContext(display, context);

    }

    XDestroyWindow(display, w);

    X11_PumpEvents(_this);

}

int 

{

    int i = 0;

    /* assert buffer is large enough to hold all SDL attributes. */ 

    SDL_assert(size >= 32);

    /* Setup our GLX attributes according to the gl_config. */

    attribs[i++] = GLX_RED_SIZE;

    attribs[i++] = _this->gl_config.red_size;

    attribs[i++] = GLX_GREEN_SIZE;

    attribs[i++] = _this->gl_config.green_size;

    attribs[i++] = GLX_BLUE_SIZE;

    attribs[i++] = _this->gl_config.blue_size;

    if (_this->gl_config.alpha_size) {

        attribs[i++] = GLX_ALPHA_SIZE;

        attribs[i++] = _this->gl_config.alpha_size;

    }

    if (_this->gl_config.double_buffer) {

        attribs[i++] = GLX_DOUBLEBUFFER;

    }

    attribs[i++] = GLX_DEPTH_SIZE;

    attribs[i++] = _this->gl_config.depth_size;

    if (_this->gl_config.stencil_size) {

        attribs[i++] = GLX_STENCIL_SIZE;

        attribs[i++] = _this->gl_config.stencil_size;

    }

    if (_this->gl_config.accum_red_size) {

        attribs[i++] = GLX_ACCUM_RED_SIZE;

        attribs[i++] = _this->gl_config.accum_red_size;

    }

    if (_this->gl_config.accum_green_size) {

        attribs[i++] = GLX_ACCUM_GREEN_SIZE;

        attribs[i++] = _this->gl_config.accum_green_size;

    }

    if (_this->gl_config.accum_blue_size) {

        attribs[i++] = GLX_ACCUM_BLUE_SIZE;

        attribs[i++] = _this->gl_config.accum_blue_size;

    }

    if (_this->gl_config.accum_alpha_size) {

        attribs[i++] = GLX_ACCUM_ALPHA_SIZE;

        attribs[i++] = _this->gl_config.accum_alpha_size;

    }

    if (_this->gl_config.stereo) {

        attribs[i++] = GLX_STEREO;

    }

    if (_this->gl_config.multisamplebuffers) {

        attribs[i++] = GLX_SAMPLE_BUFFERS_ARB;

        attribs[i++] = _this->gl_config.multisamplebuffers;

    }

    if (_this->gl_config.multisamplesamples) {

        attribs[i++] = GLX_SAMPLES_ARB;

        attribs[i++] = _this->gl_config.multisamplesamples;

    }

    if (_this->gl_config.accelerated >= 0 &&

        _this->gl_data->HAS_GLX_EXT_visual_rating) {

        attribs[i++] = GLX_VISUAL_CAVEAT_EXT;

        attribs[i++] = _this->gl_config.accelerated ? GLX_NONE_EXT :

                                                      GLX_SLOW_VISUAL_EXT;

    }

    attribs[i++] = None;

    return i;

}

XVisualInfo *

X11_GL_GetVisual(_THIS, Display * display, int screen)

{

    XVisualInfo *vinfo;

    /* 64 seems nice. */

    if (!_this->gl_data) {

        /* The OpenGL library wasn't loaded, SDL_GetError() should have info */

        return NULL;

    }

    vinfo = _this->gl_data->glXChooseVisual(display, screen, attribs);

    if (!vinfo) {

        SDL_SetError("Couldn't find matching GLX visual");

    }

    return vinfo;

}

SDL_GLContext

X11_GL_CreateContext(_THIS, SDL_Window * window)

{

    SDL_WindowData *data = (SDL_WindowData *) window->driverdata;

    Display *display = data->videodata->display;

    int screen =

        ((SDL_DisplayData *) SDL_GetDisplayForWindow(window)->driverdata)->screen;

    XWindowAttributes xattr;

    XVisualInfo v, *vinfo;

    int n;

    GLXContext context = NULL;

    /* We do this to create a clean separation between X and GLX errors. */

    XSync(display, False);

    XGetWindowAttributes(display, data->xwindow, &xattr);

    v.screen = screen;

    v.visualid = XVisualIDFromVisual(xattr.visual);

    vinfo = XGetVisualInfo(display, VisualScreenMask | VisualIDMask, &v, &n);

    if (vinfo) {

        if (_this->gl_config.major_version < 3) {

            context =

                _this->gl_data->glXCreateContext(display, vinfo, NULL, True);

        } else {

            /* If we want a GL 3.0 context or later we need to get a temporary

               context to grab the new context creation function */

            GLXContext temp_context =

                _this->gl_data->glXCreateContext(display, vinfo, NULL, True);

            if (!temp_context) {

                SDL_SetError("Could not create GL context");

                return NULL;

            } else {

                    GLX_CONTEXT_MAJOR_VERSION_ARB,

                    _this->gl_config.major_version,

                    GLX_CONTEXT_MINOR_VERSION_ARB,

                    _this->gl_config.minor_version,

                    0

                };

                /* Get a pointer to the context creation function for GL 3.0 */

                PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribs =

                    (PFNGLXCREATECONTEXTATTRIBSARBPROC) _this->gl_data->

                    glXGetProcAddress((GLubyte *)

                                      "glXCreateContextAttribsARB");

                if (!glXCreateContextAttribs) {

                    SDL_SetError("GL 3.x is not supported");

                    context = temp_context;

                } else {