C++ SDL_VideoDevice类代码示例

void SDL_WarpMouse (Uint16 x, Uint16 y)
{
 SDL_VideoDevice *video = current_video;
 SDL_VideoDevice *this  = current_video;

 if ( !video || !SDL_PublicSurface ) {
   SDL_SetError("A video mode must be set before warping mouse");
   return;
 }

 /* If we have an offset video mode, offset the mouse coordinates */
 if (this->screen->pitch == 0) {
   x += this->screen->offset / this->screen->format->BytesPerPixel;
   y += this->screen->offset;
 } else {
   x += (this->screen->offset % this->screen->pitch) /
         this->screen->format->BytesPerPixel;
   y += (this->screen->offset / this->screen->pitch);
 }

 /* This generates a mouse motion event */
 if ( video->WarpWMCursor ) {
   video->WarpWMCursor(this, x, y);
 } else {
   SDL_PrivateMouseMotion(0, 0, x, y);
 }
}

void SDL_FreeCursor (SDL_Cursor *cursor)
{
 if ( cursor ) {
   if ( cursor == SDL_cursor ) {
     SDL_SetCursor(SDL_defcursor);
   }
   if ( cursor != SDL_defcursor ) {
     SDL_VideoDevice *video = current_video;
     SDL_VideoDevice *this  = current_video;

     if ( cursor->data ) {
       SDL_free(cursor->data);
     }
     if ( cursor->save[0] ) {
       SDL_free(cursor->save[0]);
     }
     if ( video && cursor->wm_cursor ) {
       if ( video->FreeWMCursor ) {
         video->FreeWMCursor(this, cursor->wm_cursor);
       }
     }
     SDL_free(cursor);
   }
 }
}

int SDL_ShowCursor (int toggle)
{
 int showing;

 showing = (SDL_cursorstate & CURSOR_VISIBLE);
 if ( toggle >= 0 ) {
   SDL_LockCursor();
   if ( toggle ) {
     SDL_cursorstate |= CURSOR_VISIBLE;
   } else {
     SDL_cursorstate &= ~CURSOR_VISIBLE;
   }
   SDL_UnlockCursor();
   if ( (SDL_cursorstate & CURSOR_VISIBLE) != showing ) {
     SDL_VideoDevice *video = current_video;
     SDL_VideoDevice *this  = current_video;

     SDL_SetCursor(NULL);
     if ( video && video->CheckMouseMode ) {
       video->CheckMouseMode(this);
     }
   }
 } else {
   /* Query current state */ ;
 }
 return(showing ? 1 : 0);
}

SDL_Overlay *SDL_CreateYUVOverlay(int w, int h, Uint32 format,
                                  SDL_Surface *display)
{
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this  = current_video;
	const char *yuv_hwaccel;
	SDL_Overlay *overlay;

	if ( (display->flags & SDL_OPENGL) == SDL_OPENGL ) {
		SDL_SetError("YUV overlays are not supported in OpenGL mode");
		return NULL;
	}

	/* Display directly on video surface, if possible */
	if ( SDL_getenv("SDL_VIDEO_YUV_DIRECT") ) {
		if ( (display == SDL_PublicSurface) &&
		     ((SDL_VideoSurface->format->BytesPerPixel == 2) ||
		      (SDL_VideoSurface->format->BytesPerPixel == 4)) ) {
			display = SDL_VideoSurface;
		}
	}
	overlay = NULL;
        yuv_hwaccel = SDL_getenv("SDL_VIDEO_YUV_HWACCEL");
	if ( ((display == SDL_VideoSurface) && video->CreateYUVOverlay) &&
	     (!yuv_hwaccel || (SDL_atoi(yuv_hwaccel) > 0)) ) {
		overlay = video->CreateYUVOverlay(this, w, h, format, display);
	}
	/* If hardware YUV overlay failed ... */
	if ( overlay == NULL ) {
		overlay = SDL_CreateYUV_SW(this, w, h, format, display);
	}
	return overlay;
}

int SDL_SetGamma(float red, float green, float blue)
{
	int succeeded;
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this  = current_video;	

	succeeded = -1;
#ifdef USE_MATH_H
	/* Prefer using SetGammaRamp(), as it's more flexible */
	{
		Uint16 ramp[3][256];

		CalculateGammaRamp(red, ramp[0]);
		CalculateGammaRamp(green, ramp[1]);
		CalculateGammaRamp(blue, ramp[2]);
		succeeded = SDL_SetGammaRamp(ramp[0], ramp[1], ramp[2]);
	}
#else
	SDL_SetError("Gamma correction not supported");
#endif
	if ( (succeeded < 0) && video->SetGamma ) {
		SDL_ClearError();
		succeeded = video->SetGamma(this, red, green, blue);
	}
	return succeeded;
}

/* SDL_SetCursor(NULL) can be used to force the cursor redraw,
   if this is desired for any reason.  This is used when setting
   the video mode and when the SDL window gains the mouse focus.
 */
void SDL_SetCursor (SDL_Cursor *cursor)
{
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this  = current_video;

	/* Make sure that the video subsystem has been initialized */
	if ( ! video ) {
		return;
	}

	/* Prevent the event thread from moving the mouse */
	SDL_LockCursor();

	/* Set the new cursor */
	if ( cursor && (cursor != SDL_cursor) ) {
		/* Erase the current mouse position */
		if ( SHOULD_DRAWCURSOR(SDL_cursorstate) ) {
			SDL_EraseCursor(SDL_VideoSurface);
		} else if ( video->MoveWMCursor ) {
			/* If the video driver is moving the cursor directly,
			   it needs to hide the old cursor before (possibly)
			   showing the new one.  (But don't erase NULL cursor)
			 */
			if ( SDL_cursor ) {
				video->ShowWMCursor(this, NULL);
			}
		}
		SDL_cursor = cursor;
	}

	/* Draw the new mouse cursor */
	if ( SDL_cursor && (SDL_cursorstate&CURSOR_VISIBLE) ) {
		/* Use window manager cursor if possible */
		if ( SDL_cursor->wm_cursor && 
	             video->ShowWMCursor(this, SDL_cursor->wm_cursor) )
			SDL_cursorstate &= ~CURSOR_USINGSW;
		else {
			SDL_cursorstate |= CURSOR_USINGSW;
			if ( video->ShowWMCursor ) {
				video->ShowWMCursor(this, NULL);
			}
			{ int x, y;
				SDL_GetMouseState(&x, &y);
				SDL_cursor->area.x = (x - SDL_cursor->hot_x);
				SDL_cursor->area.y = (y - SDL_cursor->hot_y);
			}
			SDL_DrawCursor(SDL_VideoSurface);
		}
	} else {
		/* Erase window manager mouse (cursor not visible) */
		if ( SDL_cursor && (SDL_cursorstate & CURSOR_USINGSW) ) {
			SDL_EraseCursor(SDL_VideoSurface);
		} else {
			if ( video ) {
				video->ShowWMCursor(this, NULL);
			}
		}
	}
	SDL_UnlockCursor();
}

/* This function sets the alpha channel of a surface */
int SDL_SetAlpha (SDL_Surface *surface, Uint32 flag, Uint8 value)
{
	Uint32 oldflags = surface->flags;
	Uint32 oldalpha = surface->format->alpha;

	/* Sanity check the flag as it gets passed in */
	if ( flag & SDL_SRCALPHA ) {
		if ( flag & (SDL_RLEACCEL|SDL_RLEACCELOK) ) {
			flag = (SDL_SRCALPHA | SDL_RLEACCELOK);
		} else {
			flag = SDL_SRCALPHA;
		}
	} else {
		flag = 0;
	}

	/* Optimize away operations that don't change anything */
	if ( (flag == (surface->flags & (SDL_SRCALPHA|SDL_RLEACCELOK))) &&
	     (!flag || value == oldalpha) ) {
		return(0);
	}

	if(!(flag & SDL_RLEACCELOK) && (surface->flags & SDL_RLEACCEL))
		SDL_UnRLESurface(surface, 1);

	if ( flag ) {
		SDL_VideoDevice *video = current_video;
		SDL_VideoDevice *this  = current_video;

		surface->flags |= SDL_SRCALPHA;
		surface->format->alpha = value;
		if ( (surface->flags & SDL_HWACCEL) == SDL_HWACCEL ) {
			if ( (video->SetHWAlpha == NULL) ||
			     (video->SetHWAlpha(this, surface, value) < 0) ) {
				surface->flags &= ~SDL_HWACCEL;
			}
		}
		if ( flag & SDL_RLEACCELOK ) {
		        surface->flags |= SDL_RLEACCELOK;
		} else {
		        surface->flags &= ~SDL_RLEACCELOK;
		}
	} else {
		surface->flags &= ~SDL_SRCALPHA;
		surface->format->alpha = SDL_ALPHA_OPAQUE;
	}
	/*
	 * The representation for software surfaces is independent of
	 * per-surface alpha, so no need to invalidate the blit mapping
	 * if just the alpha value was changed. (If either is 255, we still
	 * need to invalidate.)
	 */
	if((surface->flags & SDL_HWACCEL) == SDL_HWACCEL
	   || oldflags != surface->flags
	   || (((oldalpha + 1) ^ (value + 1)) & 0x100))
		SDL_InvalidateMap(surface->map);
	return(0);
}

/* Software cursor drawing support */
SDL_Cursor * SDL_CreateCursor (Uint8 *data, Uint8 *mask,
         int w, int h, int hot_x, int hot_y)
{
 SDL_VideoDevice *video = current_video;
 int savelen;
 int i;
 SDL_Cursor *cursor;

 /* Make sure the width is a multiple of 8 */
 w = ((w+7)&~7);

 /* Sanity check the hot spot */
 if ( (hot_x < 0) || (hot_y < 0) || (hot_x >= w) || (hot_y >= h) ) {
   SDL_SetError("Cursor hot spot doesn't lie within cursor");
   return(NULL);
 }

 /* Allocate memory for the cursor */
 cursor = (SDL_Cursor *)SDL_malloc(sizeof *cursor);
 if ( cursor == NULL ) {
   SDL_OutOfMemory();
   return(NULL);
 }
 savelen = (w*4)*h;
 cursor->area.x = 0;
 cursor->area.y = 0;
 cursor->area.w = w;
 cursor->area.h = h;
 cursor->hot_x = hot_x;
 cursor->hot_y = hot_y;
 cursor->data = (Uint8 *)SDL_malloc((w/8)*h*2);
 cursor->mask = cursor->data+((w/8)*h);
 cursor->save[0] = (Uint8 *)SDL_malloc(savelen*2);
 cursor->save[1] = cursor->save[0] + savelen;
 cursor->wm_cursor = NULL;
 if ( ! cursor->data || ! cursor->save[0] ) {
   SDL_FreeCursor(cursor);
   SDL_OutOfMemory();
   return(NULL);
 }
 for ( i=((w/8)*h)-1; i>=0; --i ) {
   cursor->data[i] = data[i];
   cursor->mask[i] = mask[i] | data[i];
 }
 SDL_memset(cursor->save[0], 0, savelen*2);

 /* If the window manager gives us a good cursor, we're done! */
 if ( video->CreateWMCursor ) {
   cursor->wm_cursor = video->CreateWMCursor(video, data, mask,
             w, h, hot_x, hot_y);
 } else {
   cursor->wm_cursor = NULL;
 }
 return(cursor);
}

static int SDLCALL SDL_GobbleEvents(void *unused)
{
	event_thread = SDL_ThreadID();

#ifdef __OS2__
#ifdef USE_DOSSETPRIORITY
	/* Increase thread priority, so it will process events in time for sure! */
	DosSetPriority(PRTYS_THREAD, PRTYC_REGULAR, +16, 0);
#endif
#endif

	while ( SDL_EventQ.active ) {
		SDL_VideoDevice *video = current_video;
		SDL_VideoDevice *this  = current_video;

		/* Get events from the video subsystem */
		if ( video ) {
			video->PumpEvents(this);
		}

		/* Queue pending key-repeat events */
		SDL_CheckKeyRepeat();

#if !SDL_JOYSTICK_DISABLED
		/* Check for joystick state change */
		if ( SDL_numjoysticks && (SDL_eventstate & SDL_JOYEVENTMASK) ) {
			SDL_JoystickUpdate();
		}
#endif

		/* Give up the CPU for the rest of our timeslice */
		SDL_EventLock.safe = 1;
		if ( SDL_timer_running ) {
			SDL_ThreadedTimerCheck();
		}
		SDL_Delay(1);

		/* Check for event locking.
		   On the P of the lock mutex, if the lock is held, this thread
		   will wait until the lock is released before continuing.  The
		   safe flag will be set, meaning that the other thread can go
		   about it's business.  The safe flag is reset before the V,
		   so as soon as the mutex is free, other threads can see that
		   it's not safe to interfere with the event thread.
		 */
		SDL_mutexP(SDL_EventLock.lock);
		SDL_EventLock.safe = 0;
		SDL_mutexV(SDL_EventLock.lock);
	}
	SDL_SetTimerThreaded(0);
	event_thread = 0;
	return(0);
}

int SDL_SetGammaRamp(const Uint16 *red, const Uint16 *green, const Uint16 *blue)
{
	int succeeded;
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this  = current_video;	
	SDL_Surface *screen = SDL_PublicSurface;

	/* Verify the screen parameter */
	if ( !screen ) {
		SDL_SetError("No video mode has been set");
		return -1;
	}

	/* Lazily allocate the gamma tables */
	if ( ! video->gamma ) {
		SDL_GetGammaRamp(0, 0, 0);
	}

	/* Fill the gamma table with the new values */
	if ( red ) {
		SDL_memcpy(&video->gamma[0*256], red, 256*sizeof(*video->gamma));
	}
	if ( green ) {
		SDL_memcpy(&video->gamma[1*256], green, 256*sizeof(*video->gamma));
	}
	if ( blue ) {
		SDL_memcpy(&video->gamma[2*256], blue, 256*sizeof(*video->gamma));
	}

	/* Gamma correction always possible on split palettes */
	if ( (screen->flags & SDL_HWPALETTE) == SDL_HWPALETTE ) {
		SDL_Palette *pal = screen->format->palette;

		/* If physical palette has been set independently, use it */
		if(video->physpal)
		        pal = video->physpal;
		      
		SDL_SetPalette(screen, SDL_PHYSPAL,
			       pal->colors, 0, pal->ncolors);
		return 0;
	}

	/* Try to set the gamma ramp in the driver */
	succeeded = -1;
	if ( video->SetGammaRamp ) {
		succeeded = video->SetGammaRamp(this, video->gamma);
	} else {
		SDL_SetError("Gamma ramp manipulation not supported");
	}
	return succeeded;
}

/*
 * Set the color key in a blittable surface
 */
int SDL_SetColorKey (SDL_Surface *surface, Uint32 flag, Uint32 key)
{
	/* Sanity check the flag as it gets passed in */
	if ( flag & SDL_SRCCOLORKEY ) {
		if ( flag & (SDL_RLEACCEL|SDL_RLEACCELOK) ) {
			flag = (SDL_SRCCOLORKEY | SDL_RLEACCELOK);
		} else {
			flag = SDL_SRCCOLORKEY;
		}
	} else {
		flag = 0;
	}

	/* Optimize away operations that don't change anything */
	if ( (flag == (surface->flags & (SDL_SRCCOLORKEY|SDL_RLEACCELOK))) &&
	     (key == surface->format->colorkey) ) {
		return(0);
	}

	/* UnRLE surfaces before we change the colorkey */
	if ( surface->flags & SDL_RLEACCEL ) {
	        SDL_UnRLESurface(surface, 1);
	}

	if ( flag ) {
		SDL_VideoDevice *video = current_video;
		SDL_VideoDevice *this  = current_video;


		surface->flags |= SDL_SRCCOLORKEY;
		surface->format->colorkey = key;
		if ( (surface->flags & SDL_HWACCEL) == SDL_HWACCEL ) {
			if ( (video->SetHWColorKey == NULL) ||
			     (video->SetHWColorKey(this, surface, key) < 0) ) {
				surface->flags &= ~SDL_HWACCEL;
			}
		}
		if ( flag & SDL_RLEACCELOK ) {
			surface->flags |= SDL_RLEACCELOK;
		} else {
			surface->flags &= ~SDL_RLEACCELOK;
		}
	} else {
		surface->flags &= ~(SDL_SRCCOLORKEY|SDL_RLEACCELOK);
		surface->format->colorkey = 0;
	}
	SDL_InvalidateMap(surface->map);
	return(0);
}

void SDL_MoveCursor(int x, int y)
{
 SDL_VideoDevice *video = current_video;

 /* Erase and update the current mouse position */
 if ( SHOULD_DRAWCURSOR(SDL_cursorstate) ) {
   /* Erase and redraw mouse cursor in new position */
   SDL_LockCursor();
   SDL_EraseCursor(SDL_VideoSurface);
   SDL_cursor->area.x = (x - SDL_cursor->hot_x);
   SDL_cursor->area.y = (y - SDL_cursor->hot_y);
   SDL_DrawCursor(SDL_VideoSurface);
   SDL_UnlockCursor();
 } else if ( video->MoveWMCursor ) {
   video->MoveWMCursor(video, x, y);
 }
}

static int SDLCALL SDL_GobbleEvents(void *unused)
{
	event_thread = SDL_ThreadID();

#ifdef __OS2__
#ifdef USE_DOSSETPRIORITY
	
	DosSetPriority(PRTYS_THREAD, PRTYC_REGULAR, +16, 0);
#endif
#endif

	while ( SDL_EventQ.active ) {
		SDL_VideoDevice *video = current_video;
		SDL_VideoDevice *this  = current_video;

		
		if ( video ) {
			video->PumpEvents(this);
		}

		
		SDL_CheckKeyRepeat();

#if !SDL_JOYSTICK_DISABLED
		
		if ( SDL_numjoysticks && (SDL_eventstate & SDL_JOYEVENTMASK) ) {
			SDL_JoystickUpdate();
		}
#endif

		
		SDL_EventLock.safe = 1;
		if ( SDL_timer_running ) {
			SDL_ThreadedTimerCheck();
		}
		SDL_Delay(1);

		SDL_mutexP(SDL_EventLock.lock);
		SDL_EventLock.safe = 0;
		SDL_mutexV(SDL_EventLock.lock);
	}
	SDL_SetTimerThreaded(0);
	event_thread = 0;
	return(0);
}

int SDL_SetGamma(float red, float green, float blue)
{
	int succeeded;
	SDL_VideoDevice *video = current_video;
	SDL_VideoDevice *this  = current_video;	

	succeeded = -1;
	/* Prefer using SetGammaRamp(), as it's more flexible */
	{
		Uint16 ramp[3][256];

		CalculateGammaRamp(red, ramp[0]);
		CalculateGammaRamp(green, ramp[1]);
		CalculateGammaRamp(blue, ramp[2]);
		succeeded = SDL_SetGammaRamp(ramp[0], ramp[1], ramp[2]);
	}
	if ( (succeeded < 0) && video->SetGamma ) {
		SDL_ClearError();
		succeeded = video->SetGamma(this, red, green, blue);
	}
	return succeeded;
}

/* Run the system dependent event loops */
void SDL_PumpEvents(void)
{
	if ( !SDL_EventThread ) {
		SDL_VideoDevice *video = current_video;
		SDL_VideoDevice *this  = current_video;

		/* Get events from the video subsystem */
		if ( video ) {
			video->PumpEvents(this);
		}

		/* Queue pending key-repeat events */
		SDL_CheckKeyRepeat();

#if !SDL_JOYSTICK_DISABLED
		/* Check for joystick state change */
		if ( SDL_numjoysticks && (SDL_eventstate & SDL_JOYEVENTMASK) ) {
			SDL_JoystickUpdate();
		}
#endif
	}
}