src/video/wincommon/SDL_wingl.c
author Sam Lantinga <slouken@libsdl.org>
Sun, 16 May 2004 18:02:48 +0000
changeset 889 eac8c69b5706
parent 769 b8d311d90021
child 1261 031e093ba2a5
permissions -rw-r--r--
ate: Fri, 09 Apr 2004 20:07:10 +0200 From: Hibernatus Subject: [SDL] BUG: changing video mode in opengl + windows In WIN_GL_SetupWindow (SDL12/src/video/wincommon/SDL_wingl.c) you call WIN_GL_ResetWindow when SetPixelFormat fails. WIN_GL_ResetWindow cannot properly work in its current state, because there are several things to update once you've created a new window. At least DirectInput doesn't work anymore here (which is somewhat annoying for the player :). I think you can simply remove that function. Many games don't try to recover from that exception, that's why the newest ATI drivers emulate 16 bpp display in 32 bpp mode so the error never occurs (but the games may run much slower). Having SDL_SetVideoMode return NULL would be better than actually setting the video mode and losing focus, directinput and maybe directsound too. It also made my previous drivers crash (when switching from 32 bpp windowed to 16 bpp fullscreen).

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    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
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

#include <string.h>

/* WGL implementation of SDL OpenGL support */

#ifdef HAVE_OPENGL
#include "SDL_opengl.h"
#endif
#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;
	}
#if 0 /* This doesn't work with DirectX code (see CVS comments) */
#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 */
#endif
	{
		SDL_SetError("Unable to reset window for OpenGL context");
		status = -1;
	}
	return(status);
}

#ifdef HAVE_OPENGL
static void Init_WGL_ARB_extensions(_THIS)
{
	HWND hwnd;
	HDC hdc;
	HGLRC hglrc;
	int pformat;
	const char * (WINAPI *wglGetExtensionsStringARB)(HDC) = 0;
	
	hwnd = CreateWindow(SDL_Appname, SDL_Appname, WS_POPUP | WS_DISABLED,
	                    0, 0, 10, 10,
	                    NULL, NULL, SDL_Instance,NULL);
	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 && strstr(wglGetExtensionsStringARB(hdc),"WGL_ARB_pixel_format")) {
		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;
		else 
			this->gl_data->wgl_arb_pixel_format = 0;
	} else {
		this->gl_data->wgl_arb_pixel_format = 0;
	}
	
	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
	int i;
	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;
		}

		if ( this->gl_config.double_buffer ) {
			*iAttr ++ = WGL_DOUBLE_BUFFER_ARB;
			*iAttr ++ = GL_TRUE;
		}

		*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++ = this->gl_config.stereo;
		}

		if ( this->gl_config.multisamplebuffers ) {
			*iAttr++ = WGL_SAMPLE_BUFFERS_ARB;
			*iAttr++ = this->gl_config.multisamplebuffers;
		}

		if ( this->gl_config.multisamplesamples ) {
			*iAttr++ = WGL_SAMPLES_ARB;
			*iAttr++ = this->gl_config.multisamplesamples;
		}

		*iAttr = 0;

		/* Choose and set the closest available pixel format */
		if ( !this->gl_data->wgl_arb_pixel_format ||
		     !this->gl_data->wglChoosePixelFormatARB(GL_hdc, iAttribs, fAttribs, 1, &pixel_format, &matching) ||
		     !matching ) {
			pixel_format = ChoosePixelFormat(GL_hdc, &GL_pfd);
			this->gl_data->wgl_arb_pixel_format = 0;
		}
		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;
	
	if ( this->gl_data->wgl_arb_pixel_format ) {
		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;
		    case SDL_GL_MULTISAMPLEBUFFERS:
			wgl_attrib = WGL_SAMPLE_BUFFERS_ARB;
			break;
		    case SDL_GL_MULTISAMPLESAMPLES:
			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;
	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_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 */
	memset(this->gl_data, 0, sizeof(*this->gl_data));
	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 */