/*

SDL - Simple DirectMedia Layer

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Library General Public

License as published by the Free Software Foundation; either

version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Library General Public License for more details.

You should have received a copy of the GNU Library General Public

License along with this library; if not, write to the Free

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

Sam Lantinga

*/

#ifdef SAVE_RCSID

static char rcsid =

"@(#) $Id$";

#endif

/* WGL implementation of SDL OpenGL support */

#include "SDL_error.h"

#include "SDL_lowvideo.h"

#include "SDL_wingl_c.h"

#ifdef HAVE_OPENGL

#define DEFAULT_GL_DRIVER_PATH "OPENGL32.DLL"

#endif

/* If setting the HDC fails, we may need to recreate the window (MSDN) */

static int WIN_GL_ResetWindow(_THIS)

{

int status = 0;

int can_reset = 1;

/* If we were passed a window, then we can't create a new one */

if ( SDL_windowid ) {

can_reset = 0;

}

#ifndef _WIN32_WCE /* FIXME WinCE needs the UNICODE version of CreateWindow() */

if ( can_reset ) {

/* Save the existing window attributes */

LONG style;

RECT rect = { 0, 0, 0, 0 };

style = GetWindowLong(SDL_Window, GWL_STYLE);

GetWindowRect(SDL_Window, &rect);

DestroyWindow(SDL_Window);

SDL_Window = CreateWindow(SDL_Appname, SDL_Appname,

style,

rect.left, rect.top,

(rect.right-rect.left)+1,

(rect.top-rect.bottom)+1,

NULL, NULL, SDL_Instance, NULL);

if ( SDL_Window ) {

this->SetCaption(this, this->wm_title, this->wm_icon);

} else {

SDL_SetError("Couldn't create window");

status = -1;

}

} else

#endif /* !_WIN32_WCE */

{

SDL_SetError("Unable to reset window for OpenGL context");

status = -1;

}

return(status);

}

int WIN_GL_SetupWindow(_THIS)

{

int retval;

#ifdef HAVE_OPENGL

int pixel_format;

/* load the gl driver from a default path */

if ( ! this->gl_config.driver_loaded ) {

/* no driver has been loaded, use default (ourselves) */

if ( WIN_GL_LoadLibrary(this, NULL) < 0 ) {

return(-1);

}

}

for ( i=0; ; ++i ) {

/* Get the window device context for our OpenGL drawing */

GL_hdc = GetDC(SDL_Window);

if ( GL_hdc == NULL ) {

SDL_SetError("Unable to get DC for SDL_Window");

return(-1);

}

/* Set up the pixel format descriptor with our needed format */

memset(&GL_pfd, 0, sizeof(GL_pfd));

GL_pfd.nSize = sizeof(GL_pfd);

GL_pfd.nVersion = 1;

GL_pfd.dwFlags = (PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL);

if ( this->gl_config.double_buffer ) {

GL_pfd.dwFlags |= PFD_DOUBLEBUFFER;

}

if ( this->gl_config.stereo ) {

GL_pfd.dwFlags |= PFD_STEREO;

}

GL_pfd.iPixelType = PFD_TYPE_RGBA;

GL_pfd.cColorBits = this->gl_config.buffer_size;

GL_pfd.cRedBits = this->gl_config.red_size;

GL_pfd.cGreenBits = this->gl_config.green_size;

GL_pfd.cBlueBits = this->gl_config.blue_size;

GL_pfd.cAlphaBits = this->gl_config.alpha_size;

GL_pfd.cAccumRedBits = this->gl_config.accum_red_size;

GL_pfd.cAccumGreenBits = this->gl_config.accum_green_size;

GL_pfd.cAccumBlueBits = this->gl_config.accum_blue_size;

GL_pfd.cAccumAlphaBits = this->gl_config.accum_alpha_size;

GL_pfd.cAccumBits =

(GL_pfd.cAccumRedBits + GL_pfd.cAccumGreenBits +

GL_pfd.cAccumBlueBits + GL_pfd.cAccumAlphaBits);

GL_pfd.cDepthBits = this->gl_config.depth_size;

GL_pfd.cStencilBits = this->gl_config.stencil_size;

/* Choose and set the closest available pixel format */

pixel_format = ChoosePixelFormat(GL_hdc, &GL_pfd);

if ( !pixel_format ) {

SDL_SetError("No matching GL pixel format available");

return(-1);

}

if( !SetPixelFormat(GL_hdc, pixel_format, &GL_pfd) ) {

if ( i == 0 ) {

/* First time through, try resetting the window */

if ( WIN_GL_ResetWindow(this) < 0 ) {

return(-1);

}

continue;

}

SDL_SetError("Unable to set HDC pixel format");

return(-1);

}

/* We either succeeded or failed by this point */

break;

}

DescribePixelFormat(GL_hdc, pixel_format, sizeof(GL_pfd), &GL_pfd);

GL_hrc = this->gl_data->wglCreateContext(GL_hdc);

if( GL_hrc == NULL ) {

SDL_SetError("Unable to create GL context");

return(-1);

}

gl_active = 1;

#else

SDL_SetError("WIN driver not configured with OpenGL");

#endif

if ( gl_active ) {

retval = 0;

} else {

retval = -1;

}

return(retval);

}

void WIN_GL_ShutDown(_THIS)

{

#ifdef HAVE_OPENGL

/* Clean up OpenGL */

if ( GL_hrc ) {

this->gl_data->wglMakeCurrent(NULL, NULL);

this->gl_data->wglDeleteContext(GL_hrc);

GL_hrc = NULL;

}

if ( GL_hdc ) {

ReleaseDC(SDL_Window, GL_hdc);

GL_hdc = NULL;

}

gl_active = 0;

WIN_GL_UnloadLibrary(this);

#endif /* HAVE_OPENGL */

}

#ifdef HAVE_OPENGL

/* Make the current context active */

int WIN_GL_MakeCurrent(_THIS)

{

int retval;

retval = 0;

if ( ! this->gl_data->wglMakeCurrent(GL_hdc, GL_hrc) ) {

SDL_SetError("Unable to make GL context current");

retval = -1;

}

return(retval);

}

/* Get attribute data from glX. */

int WIN_GL_GetAttribute(_THIS, SDL_GLattr attrib, int* value)

{

int retval;

retval = 0;

switch( attrib ) {

case SDL_GL_RED_SIZE:

*value = GL_pfd.cRedBits;

break;

case SDL_GL_GREEN_SIZE:

*value = GL_pfd.cGreenBits;

break;

case SDL_GL_BLUE_SIZE:

*value = GL_pfd.cBlueBits;

break;

case SDL_GL_ALPHA_SIZE:

*value = GL_pfd.cAlphaBits;

break;

case SDL_GL_DOUBLEBUFFER:

if ( GL_pfd.dwFlags & PFD_DOUBLEBUFFER ) {

*value = 1;

} else {

*value = 0;

}

break;

case SDL_GL_BUFFER_SIZE:

*value = GL_pfd.cColorBits;

break;

case SDL_GL_DEPTH_SIZE:

*value = GL_pfd.cDepthBits;

break;

case SDL_GL_STENCIL_SIZE:

*value = GL_pfd.cStencilBits;

break;

case SDL_GL_ACCUM_RED_SIZE:

*value = GL_pfd.cAccumRedBits;

break;

case SDL_GL_ACCUM_GREEN_SIZE:

*value = GL_pfd.cAccumGreenBits;

break;

case SDL_GL_ACCUM_BLUE_SIZE:

*value = GL_pfd.cAccumBlueBits;

break;

case SDL_GL_ACCUM_ALPHA_SIZE:

*value = GL_pfd.cAccumAlphaBits;

break;

case SDL_GL_STEREO:

if ( GL_pfd.dwFlags & PFD_STEREO ) {

*value = 1;

} else {

*value = 0;

}

break;

default:

retval = -1;

break;

}

return retval;

}

void WIN_GL_SwapBuffers(_THIS)

{

SwapBuffers(GL_hdc);

}

void WIN_GL_UnloadLibrary(_THIS)

{

if ( this->gl_config.driver_loaded ) {

FreeLibrary((HMODULE)this->gl_config.dll_handle);

this->gl_data->wglGetProcAddress = NULL;

this->gl_data->wglCreateContext = NULL;

this->gl_data->wglDeleteContext = NULL;

this->gl_data->wglMakeCurrent = NULL;

this->gl_config.dll_handle = NULL;

this->gl_config.driver_loaded = 0;

}

}

/* Passing a NULL path means load pointers from the application */

int WIN_GL_LoadLibrary(_THIS, const char* path)

{

HMODULE handle;

if ( gl_active ) {

SDL_SetError("OpenGL context already created");

return -1;

}

if ( path == NULL ) {

path = DEFAULT_GL_DRIVER_PATH;

}

handle = LoadLibrary(path);

if ( handle == NULL ) {

SDL_SetError("Could not load OpenGL library");

return -1;

}

/* Unload the old driver and reset the pointers */

WIN_GL_UnloadLibrary(this);

/* Load new function pointers */

this->gl_data->wglGetProcAddress = (void * (WINAPI *)(const char *))

GetProcAddress(handle, "wglGetProcAddress");

this->gl_data->wglCreateContext = (HGLRC (WINAPI *)(HDC))

GetProcAddress(handle, "wglCreateContext");

this->gl_data->wglDeleteContext = (BOOL (WINAPI *)(HGLRC))

GetProcAddress(handle, "wglDeleteContext");

this->gl_data->wglMakeCurrent = (BOOL (WINAPI *)(HDC, HGLRC))

GetProcAddress(handle, "wglMakeCurrent");

if ( (this->gl_data->wglGetProcAddress == NULL) ||

(this->gl_data->wglCreateContext == NULL) ||

(this->gl_data->wglDeleteContext == NULL) ||

(this->gl_data->wglMakeCurrent == NULL) ) {

SDL_SetError("Could not retrieve OpenGL functions");

FreeLibrary(handle);

return -1;

}

this->gl_config.dll_handle = handle;

strcpy(this->gl_config.driver_path, path);

this->gl_config.driver_loaded = 1;

return 0;

}

void *WIN_GL_GetProcAddress(_THIS, const char* proc)

{

void *func;

/* This is to pick up extensions */

func = this->gl_data->wglGetProcAddress(proc);

if ( ! func ) {

/* This is probably a normal GL function */

func = GetProcAddress(this->gl_config.dll_handle, proc);

}

return func;

}

#endif /* HAVE_OPENGL */