/*

SDL - Simple DirectMedia Layer

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

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

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

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

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Sam Lantinga

*/

#include <string.h>

/* 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;

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

if ( !SDL_windowid ) {

/* 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);

}

static int ExtensionSupported(const char *extension, const char *extensions)

{

const char *start;

const char *where, *terminator;

/* Extension names should not have spaces. */

where = strchr(extension, ' ');

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

return 0;

if ( ! extensions )

return 0;

/* 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 = strstr(start, extension);

if (!where) break;

terminator = where + strlen(extension);

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

if (*terminator == ' ' || *terminator == '\0') return 1;

start = terminator;

}

return 0;

}

{

HWND hwnd;

HDC hdc;

HGLRC hglrc;

int pformat;

const char * (WINAPI *wglGetExtensionsStringARB)(HDC) = 0;

hdc = GetDC(hwnd);

pformat = ChoosePixelFormat(hdc, &GL_pfd);

SetPixelFormat(hdc, pformat, &GL_pfd);

hglrc = this->gl_data->wglCreateContext(hdc);

if ( hglrc ) {

this->gl_data->wglMakeCurrent(hdc, hglrc);

}

wglGetExtensionsStringARB = (const char * (WINAPI *)(HDC))

this->gl_data->wglGetProcAddress("wglGetExtensionsStringARB");

if( wglGetExtensionsStringARB ) {

extensions = wglGetExtensionsStringARB(hdc);

} else {

extensions = NULL;

}

this->gl_data->WGL_ARB_pixel_format = 0;

if( ExtensionSupported("WGL_ARB_pixel_format", extensions) ) {

this->gl_data->wglChoosePixelFormatARB =

(BOOL (WINAPI *)(HDC, const int *, const FLOAT *, UINT, int *, UINT *))

this->gl_data->wglGetProcAddress("wglChoosePixelFormatARB");

this->gl_data->wglGetPixelFormatAttribivARB =

(BOOL (WINAPI *)(HDC, int, int, UINT, const int *, int *))

this->gl_data->wglGetProcAddress("wglGetPixelFormatAttribivARB");

if( (this->gl_data->wglChoosePixelFormatARB != NULL) &&

(this->gl_data->wglGetPixelFormatAttribivARB != NULL) ) {

this->gl_data->WGL_ARB_pixel_format = 1;

}

}

if ( hglrc ) {

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

this->gl_data->wglDeleteContext(hglrc);

}

ReleaseDC(hwnd, hdc);

DestroyWindow(hwnd);

}

#endif /* HAVE_OPENGL */

int WIN_GL_SetupWindow(_THIS)

{

int retval;

#ifdef HAVE_OPENGL

unsigned int matching;

int iAttribs[64];

int *iAttr;

float fAttribs[1] = { 0 };

/* 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;

/* initialize WGL_ARB_pixel_format */

Init_WGL_ARB_extensions(this);

/* setup WGL_ARB_pixel_format attribs */

iAttr = &iAttribs[0];

*iAttr++ = WGL_DRAW_TO_WINDOW_ARB;

*iAttr++ = GL_TRUE;

*iAttr++ = WGL_ACCELERATION_ARB;

*iAttr++ = WGL_FULL_ACCELERATION_ARB;

*iAttr++ = WGL_RED_BITS_ARB;

*iAttr++ = this->gl_config.red_size;

*iAttr++ = WGL_GREEN_BITS_ARB;

*iAttr++ = this->gl_config.green_size;

*iAttr++ = WGL_BLUE_BITS_ARB;

*iAttr++ = this->gl_config.blue_size;

if ( this->gl_config.alpha_size ) {

*iAttr++ = WGL_ALPHA_BITS_ARB;

*iAttr++ = this->gl_config.alpha_size;

}

*iAttr++ = WGL_DOUBLE_BUFFER_ARB;

*iAttr++ = this->gl_config.double_buffer;

*iAttr++ = WGL_DEPTH_BITS_ARB;

*iAttr++ = this->gl_config.depth_size;

if ( this->gl_config.stencil_size ) {

*iAttr++ = WGL_STENCIL_BITS_ARB;

*iAttr++ = this->gl_config.stencil_size;

}

if ( this->gl_config.accum_red_size ) {

*iAttr++ = WGL_ACCUM_RED_BITS_ARB;

*iAttr++ = this->gl_config.accum_red_size;

}

if ( this->gl_config.accum_green_size ) {

*iAttr++ = WGL_ACCUM_GREEN_BITS_ARB;

*iAttr++ = this->gl_config.accum_green_size;

}

if ( this->gl_config.accum_blue_size ) {

*iAttr++ = WGL_ACCUM_BLUE_BITS_ARB;

*iAttr++ = this->gl_config.accum_blue_size;

}

if ( this->gl_config.accum_alpha_size ) {

*iAttr++ = WGL_ACCUM_ALPHA_BITS_ARB;

*iAttr++ = this->gl_config.accum_alpha_size;

}

if ( this->gl_config.stereo ) {

*iAttr++ = WGL_STEREO_ARB;

}

}

}

*iAttr = 0;

!this->gl_data->wglChoosePixelFormatARB(GL_hdc, iAttribs, fAttribs, 1, &pixel_format, &matching) ||

!matching ) {

pixel_format = ChoosePixelFormat(GL_hdc, &GL_pfd);

if ( !pixel_format ) {

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

return(-1);

}

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);

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;

int wgl_attrib;

switch(attrib) {

case SDL_GL_RED_SIZE:

wgl_attrib = WGL_RED_BITS_ARB;

break;

case SDL_GL_GREEN_SIZE:

wgl_attrib = WGL_GREEN_BITS_ARB;

break;

case SDL_GL_BLUE_SIZE:

wgl_attrib = WGL_BLUE_BITS_ARB;

break;

case SDL_GL_ALPHA_SIZE:

wgl_attrib = WGL_ALPHA_BITS_ARB;

break;

case SDL_GL_DOUBLEBUFFER:

wgl_attrib = WGL_DOUBLE_BUFFER_ARB;

break;

case SDL_GL_BUFFER_SIZE:

wgl_attrib = WGL_COLOR_BITS_ARB;

break;

case SDL_GL_DEPTH_SIZE:

wgl_attrib = WGL_DEPTH_BITS_ARB;

break;

case SDL_GL_STENCIL_SIZE:

wgl_attrib = WGL_STENCIL_BITS_ARB;

break;

case SDL_GL_ACCUM_RED_SIZE:

wgl_attrib = WGL_ACCUM_RED_BITS_ARB;

break;

case SDL_GL_ACCUM_GREEN_SIZE:

wgl_attrib = WGL_ACCUM_GREEN_BITS_ARB;

break;

case SDL_GL_ACCUM_BLUE_SIZE:

wgl_attrib = WGL_ACCUM_BLUE_BITS_ARB;

break;

case SDL_GL_ACCUM_ALPHA_SIZE:

wgl_attrib = WGL_ACCUM_ALPHA_BITS_ARB;

break;

case SDL_GL_STEREO:

wgl_attrib = WGL_STEREO_ARB;

break;

wgl_attrib = WGL_SAMPLE_BUFFERS_ARB;

break;

wgl_attrib = WGL_SAMPLES_ARB;

break;

default:

return(-1);

}

this->gl_data->wglGetPixelFormatAttribivARB(GL_hdc, pixel_format, 0, 1, &wgl_attrib, value);

return 0;

}

retval = 0;

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;

case SDL_GL_MULTISAMPLEBUFFERS:

*value = 0;

break;

case SDL_GL_MULTISAMPLESAMPLES:

*value = 1;

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_data->wglChoosePixelFormatARB = NULL;

this->gl_data->wglGetPixelFormatAttribivARB = 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 */