sdl_video.c

Simple DirectMedia Layer - Simple DirectMedia Layer 是一个跨平台的多媒体库设计用来提供快速图形framebuffer和音频驱动。应用MPEG为软件

			--i;
			*w = sizes[i]->w;
			*h = sizes[i]->h;
			*BitsPerPixel = SDL_closest_depths[table][b];
			supported = 1;
		}
	}
	if ( ! supported ) {
		SDL_SetError("No video mode large enough for %dx%d", *w, *h);
	}
	return(supported);
}

/* This should probably go somewhere else -- like SDL_surface.c */
static void SDL_ClearSurface(SDL_Surface *surface)
{
	Uint32 black;

	black = SDL_MapRGB(surface->format, 0, 0, 0);
	SDL_FillRect(surface, NULL, black);
	if ((surface->flags&SDL_HWSURFACE) && (surface->flags&SDL_DOUBLEBUF)) {
		SDL_Flip(surface);
		SDL_FillRect(surface, NULL, black);
	}
	SDL_Flip(surface);
}

/*
 * Create a shadow surface suitable for fooling the app. :-)
 */
static void SDL_CreateShadowSurface(int depth)
{
	Uint32 Rmask, Gmask, Bmask;

	/* Allocate the shadow surface */
	if ( depth == (SDL_VideoSurface->format)->BitsPerPixel ) {
		Rmask = (SDL_VideoSurface->format)->Rmask;
		Gmask = (SDL_VideoSurface->format)->Gmask;
		Bmask = (SDL_VideoSurface->format)->Bmask;
	} else {
		Rmask = Gmask = Bmask = 0;
	}
	SDL_ShadowSurface = SDL_CreateRGBSurface(SDL_SWSURFACE,
				SDL_VideoSurface->w, SDL_VideoSurface->h,
						depth, Rmask, Gmask, Bmask, 0);
	if ( SDL_ShadowSurface == NULL ) {
		return;
	}

	/* 8-bit shadow surfaces report that they have exclusive palette */
	if ( SDL_ShadowSurface->format->palette ) {
		SDL_ShadowSurface->flags |= SDL_HWPALETTE;
		if ( depth == (SDL_VideoSurface->format)->BitsPerPixel ) {
			memcpy(SDL_ShadowSurface->format->palette->colors,
				SDL_VideoSurface->format->palette->colors,
				SDL_VideoSurface->format->palette->ncolors*
							sizeof(SDL_Color));
		} else {
			SDL_DitherColors(
			SDL_ShadowSurface->format->palette->colors, depth);
		}
	}

	/* If the video surface is resizable, the shadow should say so */
	if ( (SDL_VideoSurface->flags & SDL_RESIZABLE) == SDL_RESIZABLE ) {
		SDL_ShadowSurface->flags |= SDL_RESIZABLE;
	}
	/* If the video surface has no frame, the shadow should say so */
	if ( (SDL_VideoSurface->flags & SDL_NOFRAME) == SDL_NOFRAME ) {
		SDL_ShadowSurface->flags |= SDL_NOFRAME;
	}
	/* If the video surface is fullscreen, the shadow should say so */
	if ( (SDL_VideoSurface->flags & SDL_FULLSCREEN) == SDL_FULLSCREEN ) {
		SDL_ShadowSurface->flags |= SDL_FULLSCREEN;
	}
	/* If the video surface is flippable, the shadow should say so */
	if ( (SDL_VideoSurface->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
		SDL_ShadowSurface->flags |= SDL_DOUBLEBUF;
	}
	return;
}

/*
 * Set the requested video mode, allocating a shadow buffer if necessary.
 */
SDL_Surface * SDL_SetVideoMode (int width, int height, int bpp, Uint32 flags)
{
	SDL_VideoDevice *video, *this;
	SDL_Surface *prev_mode, *mode;
	int video_w;
	int video_h;
	int video_bpp;
	int is_opengl;
	SDL_GrabMode saved_grab;

	/* Start up the video driver, if necessary..
	   WARNING: This is the only function protected this way!
	 */
	if ( ! current_video ) {
		if ( SDL_Init(SDL_INIT_VIDEO|SDL_INIT_NOPARACHUTE) < 0 ) {
			return(NULL);
		}
	}
	this = video = current_video;

	/* Default to the current video bpp */
	if ( bpp == 0 ) {
		flags |= SDL_ANYFORMAT;
		bpp = SDL_VideoSurface->format->BitsPerPixel;
	}

	/* Get a good video mode, the closest one possible */
	video_w = width;
	video_h = height;
	video_bpp = bpp;
	if ( ! SDL_GetVideoMode(&video_w, &video_h, &video_bpp, flags) ) {
		return(NULL);
	}

	/* Check the requested flags */
	/* There's no palette in > 8 bits-per-pixel mode */
	if ( video_bpp > 8 ) {
		flags &= ~SDL_HWPALETTE;
	}
#if 0
	if ( (flags&SDL_FULLSCREEN) != SDL_FULLSCREEN ) {
		/* There's no windowed double-buffering */
		flags &= ~SDL_DOUBLEBUF;
	}
#endif
	if ( (flags&SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
		/* Use hardware surfaces when double-buffering */
		flags |= SDL_HWSURFACE;
	}

	is_opengl = ( ( flags & SDL_OPENGL ) == SDL_OPENGL );
	if ( is_opengl ) {
		/* These flags are for 2D video modes only */
		flags &= ~(SDL_HWSURFACE|SDL_DOUBLEBUF);
	}

	/* Reset the keyboard here so event callbacks can run */
	SDL_ResetKeyboard();
	SDL_ResetMouse();

	/* Clean up any previous video mode */
	if ( SDL_PublicSurface != NULL ) {
		SDL_PublicSurface = NULL;
	}
	if ( SDL_ShadowSurface != NULL ) {
		SDL_Surface *ready_to_go;
		ready_to_go = SDL_ShadowSurface;
		SDL_ShadowSurface = NULL;
		SDL_FreeSurface(ready_to_go);
	}
	if ( video->physpal ) {
		free(video->physpal->colors);
		free(video->physpal);
		video->physpal = NULL;
	}
	if( video->gammacols) {
	        free(video->gammacols);
		video->gammacols = NULL;
	}

	/* Save the previous grab state and turn off grab for mode switch */
	saved_grab = SDL_WM_GrabInputOff();

	/* Try to set the video mode, along with offset and clipping */
	prev_mode = SDL_VideoSurface;
	SDL_LockCursor();
	SDL_VideoSurface = NULL;	/* In case it's freed by driver */
	mode = video->SetVideoMode(this, prev_mode,video_w,video_h,video_bpp,flags);
	if ( mode ) { /* Prevent resize events from mode change */
	    SDL_PrivateResize(mode->w, mode->h);

	    /* Sam - If we asked for OpenGL mode, and didn't get it, fail */
	    if ( is_opengl && !(mode->flags & SDL_OPENGL) ) {
		mode = NULL;
	    }
        }
	/*
	 * rcg11292000
	 * If you try to set an SDL_OPENGL surface, and fail to find a
	 * matching  visual, then the next call to SDL_SetVideoMode()
	 * will segfault, since  we no longer point to a dummy surface,
	 * but rather NULL.
	 * Sam 11/29/00
	 * WARNING, we need to make sure that the previous mode hasn't
	 * already been freed by the video driver.  What do we do in
	 * that case?  Should we call SDL_VideoInit() again?
	 */
	SDL_VideoSurface = (mode != NULL) ? mode : prev_mode;

	if ( (mode != NULL) && (!is_opengl) ) {
		/* Sanity check */
		if ( (mode->w < width) || (mode->h < height) ) {
			SDL_SetError("Video mode smaller than requested");
			return(NULL);
		}

		/* If we have a palettized surface, create a default palette */
		if ( mode->format->palette ) {
	        	SDL_PixelFormat *vf = mode->format;
			SDL_DitherColors(vf->palette->colors, vf->BitsPerPixel);
			video->SetColors(this, 0, vf->palette->ncolors,
			                           vf->palette->colors);
		}

		/* Clear the surface to black */
		video->offset_x = 0;
		video->offset_y = 0;
		mode->offset = 0;
		SDL_SetClipRect(mode, NULL);
		SDL_ClearSurface(mode);

		/* Now adjust the offsets to match the desired mode */
		video->offset_x = (mode->w-width)/2;
		video->offset_y = (mode->h-height)/2;
		mode->offset = video->offset_y*mode->pitch +
				video->offset_x*mode->format->BytesPerPixel;
#ifdef DEBUG_VIDEO
  fprintf(stderr,
	"Requested mode: %dx%dx%d, obtained mode %dx%dx%d (offset %d)\n",
		width, height, bpp,
		mode->w, mode->h, mode->format->BitsPerPixel, mode->offset);
#endif
		mode->w = width;
		mode->h = height;
		SDL_SetClipRect(mode, NULL);
	}
	SDL_ResetCursor();
	SDL_UnlockCursor();

	/* If we failed setting a video mode, return NULL... (Uh Oh!) */
	if ( mode == NULL ) {
		return(NULL);
	}

	/* If there is no window manager, set the SDL_NOFRAME flag */
	if ( ! video->info.wm_available ) {
		mode->flags |= SDL_NOFRAME;
	}

	/* Reset the mouse cursor and grab for new video mode */
	SDL_SetCursor(NULL);
	if ( video->UpdateMouse ) {
		video->UpdateMouse(this);
	}
	SDL_WM_GrabInput(saved_grab);
	SDL_GetRelativeMouseState(NULL, NULL); /* Clear first large delta */

	/* If we're running OpenGL, make the context current */
	if ( (video->screen->flags & SDL_OPENGL) &&
	      video->GL_MakeCurrent ) {
		if ( video->GL_MakeCurrent(this) < 0 ) {
			return(NULL);
		}
	}

	/* Set up a fake SDL surface for OpenGL "blitting" */
	if ( (flags & SDL_OPENGLBLIT) == SDL_OPENGLBLIT ) {
		/* Load GL functions for performing the texture updates */
#ifdef HAVE_OPENGL
#define SDL_PROC(ret,func,params) \
do { \
	video->func = SDL_GL_GetProcAddress(#func); \
	if ( ! video->func ) { \
		SDL_SetError("Couldn't load GL function: %s\n", #func); \
		return(NULL); \
	} \
} while ( 0 );
#include "SDL_glfuncs.h"
#undef SDL_PROC	

		/* Create a software surface for blitting */
#ifdef GL_VERSION_1_2
		/* If the implementation either supports the packed pixels
		   extension, or implements the core OpenGL 1.2 API, it will
		   support the GL_UNSIGNED_SHORT_5_6_5 texture format.
		 */
		if ( (bpp == 16) &&
		     (strstr((const char *)video->glGetString(GL_EXTENSIONS), "GL_EXT_packed_pixels") ||
		     (atof((const char *)video->glGetString(GL_VERSION)) >= 1.2f))
		   ) {
			video->is_32bit = 0;
			SDL_VideoSurface = SDL_CreateRGBSurface(
				flags, 
				width, 
				height,  
				16,
				31 << 11,
				63 << 5,
				31,
				0
				);
		}
		else
#endif /* OpenGL 1.2 */
		{
			video->is_32bit = 1;
			SDL_VideoSurface = SDL_CreateRGBSurface(
				flags, 
				width, 
				height, 
				32, 
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
				0x000000FF,
				0x0000FF00,
				0x00FF0000,
				0xFF000000
#else
				0xFF000000,
				0x00FF0000,
				0x0000FF00,
				0x000000FF
#endif
				);
		}
		if ( ! SDL_VideoSurface ) {
			return(NULL);
		}
		SDL_VideoSurface->flags = mode->flags | SDL_OPENGLBLIT;

		/* Free the original video mode surface (is this safe?) */
		SDL_FreeSurface(mode);

                /* Set the surface completely opaque & white by default */
		memset( SDL_VideoSurface->pixels, 255, SDL_VideoSurface->h * SDL_VideoSurface->pitch );
		video->glGenTextures( 1, &video->texture );
		video->glBindTexture( GL_TEXTURE_2D, video->texture );
		video->glTexImage2D(
			GL_TEXTURE_2D,
			0,
			video->is_32bit ? GL_RGBA : GL_RGB,
			256,
			256,
			0,
			video->is_32bit ? GL_RGBA : GL_RGB,
#ifdef GL_VERSION_1_2
			video->is_32bit ? GL_UNSIGNED_BYTE : GL_UNSIGNED_SHORT_5_6_5,
#else
			GL_UNSIGNED_BYTE,
#endif
			NULL);

		video->UpdateRects = SDL_GL_UpdateRectsLock;
#else
		SDL_SetError("Somebody forgot to #define HAVE_OPENGL");
		return(NULL);
#endif
	}

	/* Create a shadow surface if necessary */
	/* There are three conditions under which we create a shadow surface:
		1.  We need a particular bits-per-pixel that we didn't get.
		2.  We need a hardware palette and didn't get one.
		3.  We need a software surface and got a hardware surface.
	*/
	if ( !(SDL_VideoSurface->flags & SDL_OPENGL) &&
	     (
	     (  !(flags&SDL_ANYFORMAT) &&
			(SDL_VideoSurface->format->BitsPerPixel != bpp)) ||
	     (   (flags&SDL_HWPALETTE) && 
				!(SDL_VideoSurface->flags&SDL_HWPALETTE)) ||
		/* If the surface is in hardware, video writes are visible
		   as soon as they are performed, so we need to buffer them
		 */
	     (   ((flags&SDL_HWSURFACE) == SDL_SWSURFACE) &&
				(SDL_VideoSurface->flags&SDL_HWSURFACE))
	     ) ) {
		SDL_CreateShadowSurface(bpp);
		if ( SDL_ShadowSurface == NULL ) {
			SDL_SetError("Couldn't create shadow surface");
			return(NULL);
		}
		SDL_PublicSurface = SDL_ShadowSurface;
	} else {
		SDL_PublicSurface = SDL_VideoSurface;
	}
	video->info.vfmt = SDL_VideoSurface->format;

	/* We're done! */
	return(SDL_PublicSurface);
}

/* 
 * Convert a surface into the video pixel format.
 */
SDL_Surface * SDL_DisplayFormat (SDL_Surface *surface)
{
	Uint32 flags;

	if ( ! SDL_PublicSurface ) {
		SDL_SetError("No video mode has been set");
		return(NULL);
	}
	/* Set the flags appropriate for copying to display surface */
	if (((SDL_PublicSurface->flags&SDL_HWSURFACE) == SDL_HWSURFACE) && current_video->info.blit_hw)
		flags = SDL_HWSURFACE;
	else 
		flags = SDL_SWSURFACE;
#ifdef AUTORLE_DISPLAYFORMAT
	flags |= (surface->flags & (SDL_SRCCOLORKEY|SDL_SRCALPHA));
	flags |= SDL_RLEACCELOK;
#else
	flags |= surface->flags & (SDL_SRCCOLORKEY|SDL_SRCALPHA|SDL_RLEACCELOK);
#endif
	return(SDL_ConvertSurface(surface, SDL_PublicSurface->format, flags));
}

/*
 * Convert a surface into a format that's suitable for blitting to
 * the screen, but including an alpha channel.
 */
SDL_Surface *SDL_DisplayFormatAlpha(SDL_Surface *surface)
{
	SDL_PixelFormat *vf;
	SDL_PixelFormat *format;
	SDL_Surface *converted;
	Uint32 flags;
	/* default to ARGB8888 */
	Uint32 amask = 0xff000000;
	Uint32 rmask = 0x00ff0000;
	Uint32 gmask = 0x0000ff00;
	Uint32 bmask = 0x000000ff;

	if ( ! SDL_PublicSurface ) {
		SDL_SetError("No video mode has been set");
		return(NULL);
	}
	vf = SDL_PublicSurface->format;

	switch(vf->BytesPerPixel) {
	    case 2:
		/* For XGY5[56]5, use, AXGY8888, where {X, Y} = {R, B}.
		   For anything else (like ARGB4444) it doesn't matter
		   since we have no special code for it anyway */
		if ( (vf->Rmask == 0x1f) &&
		     (vf->Bmask == 0xf800 || vf->Bmask == 0x7c00)) {
			rmask = 0xff;
			bmask = 0xff0000;
		}
		break;

	    case 3:
	    case 4:
		/* Keep the video format, as long as the high 8 bits are
		   unused or alpha */
		if ( (vf->Rmask == 0xff) && (vf->Bmask == 0xff0000) ) {
			rmask = 0xff;
			bmask = 0xff0000;
		}
		break;

	    default:
		/* We have no other optimised formats right now. When/if a new
		   optimised alpha format is written, add the converter here */
		break;
	}
	format = SDL_AllocFormat(32, rmask, gmask, bmask, amask);
	flags = SDL_PublicSurface->flags & SDL_HWSURFACE;
	flags |= surface->flags & (SDL_SRCALPHA | SDL_RLEACCELOK);
	converted = SDL_ConvertSurface(surface, format, flags);
	SDL_FreeFormat(format);
	return(converted);
}

/*