int VBE_getPalette(long start, long num, char *palettebuffer){    SDL_Color *sdlp = surface->format->palette->colors + start;    char *p = palettebuffer + (start * 4);    int i;    for (i = 0; i < num; i++)    {        *p++ = (Uint8) ((((float) sdlp->b) / 255.0) * 63.0);        *p++ = (Uint8) ((((float) sdlp->g) / 255.0) * 63.0);        *p++ = (Uint8) ((((float) sdlp->r) / 255.0) * 63.0);        *p++ = sdlp->unused;   /* This byte is unused in both SDL and BUILD. */        sdlp++;    } /* for */    return(1);} /* VBE_getPalette */void _uninitengine(void){   SDL_QuitSubSystem(SDL_INIT_VIDEO);} /* _uninitengine */void uninitvesa(void){   SDL_QuitSubSystem(SDL_INIT_VIDEO);} /* uninitvesa */int setupmouse(void){    SDL_GrabMode mode = SDL_GRAB_OFF;    if (surface == NULL)        return(0);    if (mouse_grabbed)        mode = SDL_GRAB_ON;    SDL_WM_GrabInput(mode);    SDL_ShowCursor(0);    mouse_x = surface->w / 2;    mouse_y = surface->h / 2;    mouse_relative_x = mouse_relative_y = 0;        /*         * this global usually gets set by BUILD, but it's a one-shot         *  deal, and we may not have an SDL surface at that point. --ryan.         */    moustat = 1;    return(1);} /* setupmouse */void readmousexy(short *x, short *y){    if (x) *x = mouse_relative_x << 2;    if (y) *y = mouse_relative_y << 2;    mouse_relative_x = mouse_relative_y = 0;} /* readmousexy */void readmousebstatus(short *bstatus){    if (bstatus)        *bstatus = mouse_buttons;} /* readmousebstatus */static unsigned char mirrorcolor = 0;void _updateScreenRect(long x, long y, long w, long h){    if (renderer == RENDERER_SOFTWARE)        SDL_UpdateRect(surface, x, y, w, h);} /* _updatescreenrect */void _nextpage(void){    Uint32 ticks;    handle_events();    if (renderer == RENDERER_SOFTWARE)    {        if (qsetmode == 200)            memcpy(surface->pixels, (const void *) frameplace, surface->w * surface->h);        SDL_UpdateRect(surface, 0, 0, 0, 0);        /*SDL_Flip(surface);  !!! */    } /* if */#ifdef USE_OPENGL    else if (renderer == RENDERER_OPENGL3D)    {        opengl_swapbuffers();    } /* else if */#endif    if ((debug_hall_of_mirrors) && (qsetmode == 200) && (frameplace))    {        memset((void *) frameplace, mirrorcolor, surface->w * surface->h);        mirrorcolor++;    } /* if */    ticks = SDL_GetTicks();    total_render_time = (ticks - last_render_ticks);    if (total_render_time > 1000)    {        total_rendered_frames = 0;        total_render_time = 1;        last_render_ticks = ticks;    } /* if */    total_rendered_frames++;} /* _nextpage */unsigned char readpixel(long offset){    return( *((unsigned char *) offset) );} /* readpixel */void drawpixel(long offset, Uint8 pixel){    *((unsigned char *) offset) = pixel;} /* drawpixel *//* !!! These are incorrect. */void drawpixels(long offset, Uint16 pixels){    Uint8 *surface_end;    Uint16 *pos;                printf("Blargh!\n");                exit(91);    if (SDL_MUSTLOCK(surface))        SDL_LockSurface(surface);    surface_end = (((Uint8 *) surface->pixels) + (surface->w * surface->h)) - 2;    pos = (Uint16 *) (((Uint8 *) surface->pixels) + offset);    if ((pos >= (Uint16 *) surface->pixels) && (pos < (Uint16 *) surface_end))        *pos = pixels;    if (SDL_MUSTLOCK(surface))        SDL_UnlockSurface(surface);} /* drawpixels */void drawpixelses(long offset, Uint32 pixelses){    Uint8 *surface_end;    Uint32 *pos;                printf("Blargh!\n");                exit(91);    if (SDL_MUSTLOCK(surface))        SDL_LockSurface(surface);    surface_end = (((Uint8 *)surface->pixels) + (surface->w * surface->h)) - 2;    pos = (Uint32 *) (((Uint8 *) surface->pixels) + offset);    if ((pos >= (Uint32 *) surface->pixels) && (pos < (Uint32 *) surface_end))        *pos = pixelses;    if (SDL_MUSTLOCK(surface))        SDL_UnlockSurface(surface);} /* drawpixelses *//* Fix this up The Right Way (TM) - DDOI */void setcolor16(int col){	drawpixel_color = col;}void drawpixel16(long offset){    drawpixel(((long) surface->pixels + offset), drawpixel_color);} /* drawpixel16 */void fillscreen16(long offset, long color, long blocksize){    Uint8 *surface_end;    Uint8 *wanted_end;    Uint8 *pixels;#if (defined USE_OPENGL)    if (renderer == RENDERER_OPENGL3D)    {        /* !!! dglClearColor() ... */        return;    } /* if */#endif    if (SDL_MUSTLOCK(surface))        SDL_LockSurface(surface);    pixels = get_framebuffer();    /* Make this function pageoffset aware - DDOI */    if (!pageoffset) { 	    offset = offset << 3;	    offset += 640*336;    }    surface_end = (pixels + (surface->w * surface->h)) - 1;    wanted_end = (pixels + offset) + blocksize;    if (offset < 0)        offset = 0;    if (wanted_end > surface_end)        blocksize = ((unsigned long) surface_end) - ((unsigned long) pixels + offset);    memset(pixels + offset, (int) color, blocksize);    if (SDL_MUSTLOCK(surface))        SDL_UnlockSurface(surface);    _nextpage();} /* fillscreen16 *//* Most of this line code is taken from Abrash's "Graphics Programming Blackbook".Remember, sharing code is A Good Thing. AH */inline void DrawHorizontalRun (char **ScreenPtr, int XAdvance, int RunLength, char Color){    int i;    char *WorkingScreenPtr = *ScreenPtr;    for (i=0; i<RunLength; i++)    {        *WorkingScreenPtr = Color;        WorkingScreenPtr += XAdvance;    }    WorkingScreenPtr += surface->w;    *ScreenPtr = WorkingScreenPtr;}inline void DrawVerticalRun (char **ScreenPtr, int XAdvance, int RunLength, char Color){    int i;    char *WorkingScreenPtr = *ScreenPtr;    for (i=0; i<RunLength; i++)    {      	*WorkingScreenPtr = Color;    	WorkingScreenPtr += surface->w;    }    WorkingScreenPtr += XAdvance;    *ScreenPtr = WorkingScreenPtr;}void drawline16(long XStart, long YStart, long XEnd, long YEnd, char Color){    int Temp, AdjUp, AdjDown, ErrorTerm, XAdvance, XDelta, YDelta;    int WholeStep, InitialPixelCount, FinalPixelCount, i, RunLength;    char *ScreenPtr;    long dx, dy;    if (SDL_MUSTLOCK(surface))        SDL_LockSurface(surface);	dx = XEnd-XStart; dy = YEnd-YStart;	if (dx >= 0)	{		if ((XStart > 639) || (XEnd < 0)) return;		if (XStart < 0) { if (dy) YStart += scale(0-XStart,dy,dx); XStart = 0; }		if (XEnd > 639) { if (dy) YEnd += scale(639-XEnd,dy,dx); XEnd = 639; }	}	else	{		if ((XEnd > 639) || (XStart < 0)) return;		if (XEnd < 0) { if (dy) YEnd += scale(0-XEnd,dy,dx); XEnd = 0; }		if (XStart > 639) { if (dy) YStart += scale(639-XStart,dy,dx); XStart = 639; }	}	if (dy >= 0)	{		if ((YStart >= ydim16) || (YEnd < 0)) return;		if (YStart < 0) { if (dx) XStart += scale(0-YStart,dx,dy); YStart = 0; }		if (YEnd >= ydim16) { if (dx) XEnd += scale(ydim16-1-YEnd,dx,dy); YEnd = ydim16-1; }	}	else	{		if ((YEnd >= ydim16) || (YStart < 0)) return;		if (YEnd < 0) { if (dx) XEnd += scale(0-YEnd,dx,dy); YEnd = 0; }		if (YStart >= ydim16) { if (dx) XStart += scale(ydim16-1-YStart,dx,dy); YStart = ydim16-1; }	}	/* Make sure the status bar border draws correctly - DDOI */	if (!pageoffset) { YStart += 336; YEnd += 336; }    /* We'll always draw top to bottom */    if (YStart > YEnd) {        Temp = YStart;        YStart = YEnd;        YEnd = Temp;        Temp = XStart;        XStart = XEnd;        XEnd = Temp;    }    /* Point to the bitmap address first pixel to draw */    ScreenPtr = (char *) (get_framebuffer()) + XStart + (surface->w * YStart);    /* Figure out whether we're going left or right, and how far we're going horizontally */    if ((XDelta = XEnd - XStart) < 0)    {        XAdvance = (-1);        XDelta = -XDelta;    } else {        XAdvance = 1;    }    /* Figure out how far we're going vertically */    YDelta = YEnd - YStart;    /* Special cases: Horizontal, vertical, and diagonal lines */    if (XDelta == 0)    {        for (i=0; i <= YDelta; i++)        {            *ScreenPtr = Color;            ScreenPtr += surface->w;        }        UNLOCK_SURFACE_AND_RETURN;    }    if (YDelta == 0)    {    	for (i=0; i <= XDelta; i++)    	{      	    *ScreenPtr = Color;    	    ScreenPtr += XAdvance;    	}        UNLOCK_SURFACE_AND_RETURN;    }    if (XDelta == YDelta)    {    	for (i=0; i <= XDelta; i++)        {            *ScreenPtr = Color;            ScreenPtr += XAdvance + surface->w;        }        UNLOCK_SURFACE_AND_RETURN;    }    /* Determine whether the line is X or Y major, and handle accordingly */    if (XDelta >= YDelta) /* X major line */    {        WholeStep = XDelta / YDelta;        AdjUp = (XDelta % YDelta) * 2;        AdjDown = YDelta * 2;        ErrorTerm = (XDelta % YDelta) - (YDelta * 2);        InitialPixelCount = (WholeStep / 2) + 1;        FinalPixelCount = InitialPixelCount;        if ((AdjUp == 0) && ((WholeStep & 0x01) == 0)) InitialPixelCount--;        if ((WholeStep & 0x01) != 0) ErrorTerm += YDelta;        DrawHorizontalRun(&ScreenPtr, XAdvance, InitialPixelCount, Color);        for (i=0; i<(YDelta-1); i++)        {            RunLength = WholeStep;            if ((ErrorTerm += AdjUp) > 0)            {        	RunLength ++;        	ErrorTerm -= AdjDown;            }            DrawHorizontalRun(&ScreenPtr, XAdvance, RunLength, Color);         }         DrawHorizontalRun(&ScreenPtr, XAdvance, FinalPixelCount, Color);         UNLOCK_SURFACE_AND_RETURN;    } else {	/* Y major line */    	WholeStep = YDelta / XDelta;    	AdjUp = (YDelta % XDelta) * 2;    	AdjDown = XDelta * 2;        ErrorTerm = (YDelta % XDelta) - (XDelta * 2);        InitialPixelCount = (WholeStep / 2) + 1;        FinalPixelCount = InitialPixelCount;        if ((AdjUp == 0) && ((WholeStep & 0x01) == 0)) InitialPixelCount --;        if ((WholeStep & 0x01) != 0) ErrorTerm += XDelta;        DrawVerticalRun(&ScreenPtr, XAdvance, InitialPixelCount, Color);        for (i=0; i<(XDelta-1); i++)        {            RunLength = WholeStep;            if ((ErrorTerm += AdjUp) > 0)            {            	RunLength ++;            	ErrorTerm -= AdjDown;            }            DrawVerticalRun(&ScreenPtr, XAdvance, RunLength, Color);        }        DrawVerticalRun(&ScreenPtr, XAdvance, FinalPixelCount, Color);        UNLOCK_SURFACE_AND_RETURN;     }} /* drawline16 */void clear2dscreen(void){    SDL_Rect rect;    rect.x = rect.y = 0;    rect.w = surface->w;	if (qsetmode == 350)        rect.h = 350;	else if (qsetmode == 480)	{		if (ydim16 <= 336)            rect.h = 336;        else            rect.h = 480;	} /* else if */    SDL_FillRect(surface, &rect, 0);} /* clear2dscreen */void _idle(void){    handle_events();    SDL_Delay(1);} /* _idle */void *_getVideoBase(void){    return((void *) surface->pixels);}void setactivepage(long dapagenum){	/* !!! Is this really still needed? - DDOI */    /*fprintf(stderr, "%s, line %d; setactivepage(): STUB.\n", __FILE__, __LINE__);*/} /* setactivepage */void limitrate(void){    /* this is a no-op in SDL. It was for buggy VGA cards in DOS. */} /* limitrate */Uint32 _timer_catcher(Uint32 interval, void *bleh){    timerhandler();    return(1);} /* _timer_catcher */void inittimer(void){    SDL_ClearError();    primary_timer = SDL_AddTimer(1000 / PLATFORM_TIMER_HZ, _timer_catcher, NULL);    if (primary_timer == NULL)    {        fprintf(stderr, "BUILDSDL: -ERROR- Problem initializing primary timer!\n");        fprintf(stderr, "BUILDSDL:  Reason: [%s]\n", SDL_GetError());        SDL_Quit();        exit(2);    } /* if */}void uninittimer(void){    if (primary_timer != NULL)    {        SDL_RemoveTimer(primary_timer);        primary_timer = NULL;    } /* if */}void initkeys(void){    /* does nothing in SDL. Key input handling is set up elsewhere. */    /* !!! why not here? */}void uninitkeys(void){    /* does nothing in SDL. Key input handling is set up elsewhere. */}void set16color_palette(void){	/* Backup old palette */	/*VBE_getPalette (0, 16, (char *)&backup_palette);*/	memcpy (&backup_palette, &palette, 16*3);	/* Set new palette */	/*VBE_setPalette (0, 16, (char *)&egapalette);*/	memcpy (&palette, &egapalette, 16*3);	in_egapalette = 1;} /* set16color_palette */void restore256_palette(void){	/*VBE_setPalette (0, 16, (char *)&backup_palette);*/	memcpy (&palette, &backup_palette, 16*3);	in_egapalette = 0;} /* restore256_palette */unsigned long getticks(void){    return(SDL_GetTicks());} /* getticks *//* end of sdl_driver.c ... */