sdl_wingl.c

SDL库 在进行视频显示程序spcaview安装时必须的库文件

		SDL_SetError("Unable to create GL context");
		return(-1);
	}
	if ( WIN_GL_MakeCurrent(this) < 0 ) {
		return(-1);
	}
	gl_active = 1;

	/* Get the wglGetPixelFormatAttribivARB pointer for the context */
	if ( this->gl_data->WGL_ARB_pixel_format ) {
		this->gl_data->wglGetPixelFormatAttribivARB =
			(BOOL (WINAPI *)(HDC, int, int, UINT, const int *, int *))
			this->gl_data->wglGetProcAddress("wglGetPixelFormatAttribivARB");
	} else {
		this->gl_data->wglGetPixelFormatAttribivARB = NULL;
	}

	/* Vsync control under Windows.  Checking glGetString here is
	 * somewhat a documented and reliable hack - it was originally
	 * as a feature added by mistake, but since so many people rely
	 * on it, it will not be removed.  strstr should be safe here.*/
	glGetStringFunc = WIN_GL_GetProcAddress(this, "glGetString");
	if ( glGetStringFunc ) {
		wglext = (const char *)glGetStringFunc(GL_EXTENSIONS);
	} else {
		/* Uh oh, something is seriously wrong here... */
		wglext = NULL;
	}
	if ( wglext && SDL_strstr(wglext, "WGL_EXT_swap_control") ) {
		this->gl_data->wglSwapIntervalEXT = WIN_GL_GetProcAddress(this, "wglSwapIntervalEXT");
		this->gl_data->wglGetSwapIntervalEXT = WIN_GL_GetProcAddress(this, "wglGetSwapIntervalEXT");
	} else {
		this->gl_data->wglSwapIntervalEXT = NULL;
		this->gl_data->wglGetSwapIntervalEXT = NULL;
	}
	if ( this->gl_config.swap_control >= 0 ) {
		if ( this->gl_data->wglSwapIntervalEXT ) {
			this->gl_data->wglSwapIntervalEXT(this->gl_config.swap_control);
		}
	}
#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)
{
#if SDL_VIDEO_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 /* SDL_VIDEO_OPENGL */
}

#if SDL_VIDEO_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 wgl. */
int WIN_GL_GetAttribute(_THIS, SDL_GLattr attrib, int* value)
{
	int retval;

	if (attrib == SDL_GL_SWAP_CONTROL) {
		if ( this->gl_data->wglGetSwapIntervalEXT ) {
			*value = this->gl_data->wglGetSwapIntervalEXT();
			return 0;
		}
		return -1;
	}

	if ( this->gl_data->wglGetPixelFormatAttribivARB ) {
		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;
		    case SDL_GL_ACCELERATED_VISUAL:
			wgl_attrib = WGL_ACCELERATION_ARB;
			this->gl_data->wglGetPixelFormatAttribivARB(GL_hdc, pixel_format, 0, 1, &wgl_attrib, value);
			if ( *value == WGL_NO_ACCELERATION_ARB ) {
				*value = SDL_FALSE;
			} else {
				*value = SDL_TRUE;
			}
			return 0;
		    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;
	    case SDL_GL_MULTISAMPLEBUFFERS:
		*value = 0;
		break;
	    case SDL_GL_MULTISAMPLESAMPLES:
		*value = 1;
		break;
	    case SDL_GL_SWAP_CONTROL:
		if ( this->gl_data->wglGetSwapIntervalEXT ) {
			*value = this->gl_data->wglGetSwapIntervalEXT();
			return 0;
		} else {
			return -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->wglGetPixelFormatAttribivARB = NULL;
		this->gl_data->wglSwapIntervalEXT = NULL;
		this->gl_data->wglGetSwapIntervalEXT = 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 */
	SDL_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");
	this->gl_data->wglSwapIntervalEXT = (void (WINAPI *)(int))
		GetProcAddress(handle, "wglSwapIntervalEXT");
	this->gl_data->wglGetSwapIntervalEXT = (int (WINAPI *)(void))
		GetProcAddress(handle, "wglGetSwapIntervalEXT");

	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;
	SDL_strlcpy(this->gl_config.driver_path, path, SDL_arraysize(this->gl_config.driver_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 /* SDL_VIDEO_OPENGL */