view src/video/riscos/SDL_riscosFullScreenVideo.c @ 4139:568c9b3c0167 SDL-1.2

* Added configure option --enable-screensaver, to allow enabling the screensaver by default. * Use XResetScreenSaver() instead of disabling screensaver entirely. Full discussion summary from Erik on the SDL mailing list: Current behaviour ================= SDL changes the user's display power management settings without permission from the user and without telling the user. The interface that it uses to do so is DPMSDisable/DPMSEnable, which should only ever be used by configuration utilities like KControl, never by normal application programs, let alone by the libraries that they use. Using an interface that is not at all intended for what SDL tries to achieve means that it will not work as it should. Firstly, the power management is completely disabled during the whole lifetime of the SDL program, not only when it should be. Secondly, it makes SDL non-reentrant, meaning that things will break when multiple SDL programs are clients of the same X server simultaneously. Thirdly, no cleanup mechanism ensures that the setting is restored if the client does not do that (for example if it crashes). In addition to that, this interface is broken on xorg, [http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries to do does not work at all on that implementation of the X Window System. (The reason that the DPMSEnable works in KControl is that it calls DPMSSetTimeout immediately after, [http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]). The problems that the current behaviour causes ============================================== 1. Information leak. When the user is away, someone might see what the user has on the display when the user counts on the screensaver preventing this. This does not even require physical access to the workstation, it is enough to see it from a distance. 2. Draining battery. An SDL program that runs on a laptop will quickly drain the battery while the user is away. The system will soon shut down and require recharging before being usable again, while it should in fact have consumed very little energy if the user's settings would have been obeyed. 3. Wasting energy. Even if battery issues are not considered, energy as such is wasted. 4. Display wear. The display may be worn out. The problems that the current behaviour tries to solve ====================================================== 1. Preventing screensaver while playing movies. Many SDL applications are media players. They have reasons to prevent screensavers from being activated while a movie is being played. When a user clicks on the play button it can be interpreted as saying "play this movie, but do not turn off the display while playing it, because I will watch it even though I do not interact with the system". 2. Preventing screensaver when some input bypasses X. Sometimes SDL uses input from another source than the X server, so that the X server is bypassed. This obviously breaks the screensaver handling. SDL tries to work around that. 3. Preventing screensaver when all input bypasses X. There is something called Direct Graphics Access mode, where a program takes control of both the display and the input devices from the X server. This obviously means that the X server can not handle the screensaver alone, since screensaver handling depends on input handling. SDL does not do what it should to help the X server to handle the screensaver. Nor does SDL take care of screeensaver handling itself. SDL simply disables the screensaver completely. How the problems should be solved ================================= The correct way for an application program to prevent the screensaver under X is to call XResetScreenSaver. This was recently discovered and implemented by the mplayer developers, [http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to wrap this in an API call (SDL_ResetScreenSaver) and implement it for the other video targets (if they do not have a corresponding call, SDL should do what it takes on that particular target, for example sending fake key events). 1. When a movie is played, the player should reset the screensaver when the animation is advanced to a new frame. The same applies to anything similar, like slideshows. 2. When the X server is handling input, it must handle all input (keyboards, mice, gamepads, ...). This is necessary, not only to be able to handle the screensaver, but also so that it can send the events to the correct (the currently active) client. If there is an input device that the X server can not handle for some reason (such as lack of Plug and Play capability), the program that handles the device as a workaround must simulate what would happen if the X server would have handled the device, by calling XResetScreenSaver when input is received from the device. 3. When the X server is not handling the input, it depends on the program that does to call XResetScreenSaver whenever an input event occurs. Alternatively the program must handle the screensaver countdown internally and call XActivateScreenSaver.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 29 Feb 2008 13:55:44 +0000
parents d910939febfa
children 782fd950bd46 c121d94672cb a1b03ba2fcd0
line wrap: on
line source

/*
    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
*/
#include "SDL_config.h"

/*
     File added by Alan Buckley (alan_baa@hotmail.com) for RISC OS compatability
	 27 March 2003

     Implements RISC OS full screen display.
*/

#include "SDL_video.h"
#include "SDL_mouse.h"
#include "../SDL_sysvideo.h"
#include "../SDL_pixels_c.h"
#include "../../events/SDL_events_c.h"

#include "SDL_riscostask.h"
#include "SDL_riscosvideo.h"
#include "SDL_riscosevents_c.h"
#include "SDL_riscosmouse_c.h"

#include "kernel.h"
#include "swis.h"
#include "unixlib/os.h"
#include "unixlib/local.h"

/* Private structures */
typedef struct tagScreenModeBlock
{
   int flags;  // mode selector flags, bit 0 = 1, bit 1-7 format specifier, 8-31 reserved
   int x_pixels;
   int y_pixels;
   int pixel_depth;  // 2^pixel_depth = bpp,i.e. 0 = 1, 1 = 2, 4 = 16, 5 = 32
   int frame_rate;   // -1 use first match
   int mode_vars[5]; // array of index, value pairs terminated by -1
} SCREENMODEBLOCK;


/* Helper functions */
void FULLSCREEN_SetDeviceMode(_THIS);
int FULLSCREEN_SetMode(int width, int height, int bpp);
void FULLSCREEN_SetupBanks(_THIS);

/* SDL video device functions for fullscreen mode */
static int FULLSCREEN_SetColors(_THIS, int firstcolor, int ncolors, SDL_Color *colors);
static int FULLSCREEN_FlipHWSurface(_THIS, SDL_Surface *surface);
void FULLSCREEN_SetWMCaption(_THIS, const char *title, const char *icon);
extern int RISCOS_GetWmInfo(_THIS, SDL_SysWMinfo *info);

/* UpdateRects variants */
static void FULLSCREEN_UpdateRects(_THIS, int numrects, SDL_Rect *rects);
static void FULLSCREEN_UpdateRectsMemCpy(_THIS, int numrects, SDL_Rect *rects);
static void FULLSCREEN_UpdateRects8bpp(_THIS, int numrects, SDL_Rect *rects);
static void FULLSCREEN_UpdateRects16bpp(_THIS, int numrects, SDL_Rect *rects);
static void FULLSCREEN_UpdateRects32bpp(_THIS, int numrects, SDL_Rect *rects);
static void FULLSCREEN_UpdateRectsOS(_THIS, int numrects, SDL_Rect *rects);

/* Local helper functions */
static int cmpmodes(const void *va, const void *vb);
static int FULLSCREEN_AddMode(_THIS, int bpp, int w, int h);
void FULLSCREEN_SetWriteBank(int bank);
void FULLSCREEN_SetDisplayBank(int bank);
static void FULLSCREEN_DisableEscape();
static void FULLSCREEN_EnableEscape();
void FULLSCREEN_BuildModeList(_THIS);

/* Following variable is set up in riskosTask.c */
extern int riscos_backbuffer; /* Create a back buffer in system memory for full screen mode */

/* Following is used to create a sprite back buffer */
extern unsigned char *WIMP_CreateBuffer(int width, int height, int bpp);

/* Fast assembler copy */
extern void RISCOS_Put32(void *to, int pixels, int pitch, int rows, void *from, int src_skip_bytes);

SDL_Surface *FULLSCREEN_SetVideoMode(_THIS, SDL_Surface *current,
				int width, int height, int bpp, Uint32 flags)
{
   _kernel_swi_regs regs;
   Uint32 Rmask = 0;
   Uint32 Gmask = 0;
   Uint32 Bmask = 0;
   int create_back_buffer = riscos_backbuffer;

   switch(bpp)
   {
	case 8:
		flags |= SDL_HWPALETTE;
		break;

	case 15:
	case 16:
		Bmask = 0x00007c00;
		Gmask = 0x000003e0;
		Rmask = 0x0000001f;
		break;

	case 32:
		Bmask = 0x00ff0000;
		Gmask = 0x0000ff00;
		Rmask = 0x000000ff;
		break;

	default:
		SDL_SetError("Pixel depth not supported");
		return NULL;
		break;
   }

   if (FULLSCREEN_SetMode(width, height, bpp) == 0)
   {
	   SDL_SetError("Couldn't set requested mode");
	   return (NULL);
   }

/* 	printf("Setting mode %dx%d\n", width, height); */

	/* Allocate the new pixel format for the screen */
	if ( ! SDL_ReallocFormat(current, bpp, Rmask, Gmask, Bmask, 0) ) {
	    RISCOS_RestoreWimpMode();
		SDL_SetError("Couldn't allocate new pixel format for requested mode");
		return(NULL);
	}

	/* Set up the new mode framebuffer */
	current->w = width;
	this->hidden->height = current->h = height;

   regs.r[0] = -1; /* -1 for current screen mode */

   /* Get screen width in bytes */
   regs.r[1] = 6; // Screen Width in bytes
   _kernel_swi(OS_ReadModeVariable, &regs, &regs);

   current->pitch = regs.r[2];

   if (flags & SDL_DOUBLEBUF)
   {
	   regs.r[0] = 2; /* Screen area */
	   _kernel_swi(OS_ReadDynamicArea, &regs, &regs);
	   
	   /* Reg 1 has amount of memory currently used for display */
	   regs.r[0] = 2; /* Screen area */
	   regs.r[1] = (current->pitch * height * 2) - regs.r[1];
	   if (_kernel_swi(OS_ChangeDynamicArea, &regs, &regs) != NULL)
	   {
		   /* Can't allocate enough screen memory for double buffer */
		   flags &= ~SDL_DOUBLEBUF;
	   }
   }
   
  	current->flags = flags | SDL_FULLSCREEN | SDL_HWSURFACE | SDL_PREALLOC;
	

	/* Need to set display banks here for double buffering */
	if (flags & SDL_DOUBLEBUF)
	{
	   FULLSCREEN_SetWriteBank(0);
	   FULLSCREEN_SetDisplayBank(1);

         create_back_buffer = 0; /* Don't need a back buffer for a double buffered display */
    }

    FULLSCREEN_SetupBanks(this);

    if (create_back_buffer)
    {
       /* If not double buffered we may need to create a memory
         ** back buffer to simulate processing on other OSes.
         ** This is turned on by setting the enviromental variable
         ** SDL$<name>$BackBuffer >= 1
         */
       if (riscos_backbuffer == 3)
          this->hidden->bank[0] = WIMP_CreateBuffer(width, height, bpp);
       else
          this->hidden->bank[0] = SDL_malloc(height * current->pitch);
       if (this->hidden->bank[0] == 0)
       {
 	       RISCOS_RestoreWimpMode();
           SDL_SetError("Couldnt allocate memory for back buffer");
           return (NULL);
       }
       /* Surface updated in programs is now a software surface */
       current->flags &= ~SDL_HWSURFACE;
    }

    /* Store address of allocated screen bank to be freed later */
    if (this->hidden->alloc_bank) SDL_free(this->hidden->alloc_bank);
    if (create_back_buffer)
    {
        this->hidden->alloc_bank = this->hidden->bank[0];
        if (riscos_backbuffer == 3)
        {
           this->hidden->bank[0] += 60; /* Start of sprite data */
           if (bpp == 8) this->hidden->bank[0] += 2048; /* 8bpp sprite have palette first */
        }
    } else
	  this->hidden->alloc_bank = 0;

    // Clear both banks to black
    SDL_memset(this->hidden->bank[0], 0, height * current->pitch);
    SDL_memset(this->hidden->bank[1], 0, height * current->pitch);

 	   this->hidden->current_bank = 0;
	   current->pixels = this->hidden->bank[0];

    /* Have to set the screen here, so SetDeviceMode will pick it up */
    this->screen = current;

	/* Reset device functions for the wimp */
	FULLSCREEN_SetDeviceMode(this);

/*	FULLSCREEN_DisableEscape(); */

	/* We're done */
	return(current);
}

/* Reset any device functions that have been changed because we have run in WIMP mode */
void FULLSCREEN_SetDeviceMode(_THIS)
{
	/* Update rects is different if we have a backbuffer */

	if (riscos_backbuffer && (this->screen->flags & SDL_DOUBLEBUF) == 0)
      {
	   switch(riscos_backbuffer)
         {
            case 2: /* ARM code full word copy */
               switch(this->screen->format->BytesPerPixel)
               {
                  case 1: /* 8bpp modes */
               	   this->UpdateRects = FULLSCREEN_UpdateRects8bpp;
                     break;
                  case 2: /* 15/16bpp modes */
               	   this->UpdateRects = FULLSCREEN_UpdateRects16bpp;
                     break;
                  case 4: /* 32 bpp modes */
               	   this->UpdateRects = FULLSCREEN_UpdateRects32bpp;
                     break;

                  default: /* Just default to the memcpy routine */
               	   this->UpdateRects = FULLSCREEN_UpdateRectsMemCpy;
                     break;
                }
               break;

            case 3: /* Use OS sprite plot routine */
               this->UpdateRects = FULLSCREEN_UpdateRectsOS;
               break;

            default: /* Old but safe memcpy */
               this->UpdateRects = FULLSCREEN_UpdateRectsMemCpy;
               break;
         }
      } else
	   this->UpdateRects = FULLSCREEN_UpdateRects; /* Default do nothing implementation */

	this->SetColors   = FULLSCREEN_SetColors;

	this->FlipHWSurface = FULLSCREEN_FlipHWSurface;

	this->SetCaption = FULLSCREEN_SetWMCaption;
	this->SetIcon = NULL;
	this->IconifyWindow = NULL;
	
	this->ShowWMCursor = RISCOS_ShowWMCursor;
	this->WarpWMCursor = FULLSCREEN_WarpWMCursor;

	this->PumpEvents = FULLSCREEN_PumpEvents;	
}

/* Query for the list of available video modes */
void FULLSCREEN_BuildModeList(_THIS)
{
	_kernel_swi_regs regs;
	char *enumInfo = NULL;
	char *enum_ptr;
	int *blockInfo;
	int j;
	int num_modes;

	/* Find out how much space we need */
	regs.r[0] = 2; /* Reason code */
	regs.r[2] = 0; /* Number of modes to skip */
	regs.r[6] = 0; /* pointer to block or 0 for count */
	regs.r[7] = 0; /* Size of block in bytes */
	_kernel_swi(OS_ScreenMode, &regs, &regs);

    num_modes = -regs.r[2];

	/* Video memory should be in r[5] */
	this->info.video_mem = regs.r[5]/1024;

	enumInfo = (unsigned char *)SDL_malloc(-regs.r[7]);
	if (enumInfo == NULL)
	{
		SDL_OutOfMemory();
		return;
	}
	/* Read mode information into block */
	regs.r[2] = 0;
	regs.r[6] = (int)enumInfo;
	regs.r[7] = -regs.r[7];
	_kernel_swi(OS_ScreenMode, &regs, &regs);

	enum_ptr = enumInfo;

	for (j =0; j < num_modes;j++)
	{
		blockInfo = (int *)enum_ptr;
		if ((blockInfo[1] & 255) == 1) /* We understand this format */
		{
			switch(blockInfo[4])
			{
			case 3: /* 8 bits per pixel */
				FULLSCREEN_AddMode(this, 8, blockInfo[2], blockInfo[3]);
				break;
			case 4: /* 15 bits per pixel */
				FULLSCREEN_AddMode(this, 15, blockInfo[2], blockInfo[3]);
				break;
			case 5: /* 32 bits per pixel */
				FULLSCREEN_AddMode(this, 32, blockInfo[2], blockInfo[3]);
				break;
			}
		}

		enum_ptr += blockInfo[0];
	}

	SDL_free(enumInfo);
		
	/* Sort the mode lists */
	for ( j=0; j<NUM_MODELISTS; ++j ) {
		if ( SDL_nummodes[j] > 0 ) {
			SDL_qsort(SDL_modelist[j], SDL_nummodes[j], sizeof *SDL_modelist[j], cmpmodes);
		}
	}
}

static int FULLSCREEN_FlipHWSurface(_THIS, SDL_Surface *surface)
{
   _kernel_swi_regs regs;
   regs.r[0] = 19;

   FULLSCREEN_SetDisplayBank(this->hidden->current_bank);
   this->hidden->current_bank ^= 1;
   FULLSCREEN_SetWriteBank(this->hidden->current_bank);
   surface->pixels = this->hidden->bank[this->hidden->current_bank];

   /* Wait for Vsync */
   _kernel_swi(OS_Byte, &regs, &regs);

	return(0);
}

/* Nothing to do if we are writing direct to hardware */
static void FULLSCREEN_UpdateRects(_THIS, int numrects, SDL_Rect *rects)
{
}

/* Safe but slower Memory copy from our allocated back buffer */
static void FULLSCREEN_UpdateRectsMemCpy(_THIS, int numrects, SDL_Rect *rects)
{
      int j;
      char *to, *from;
      int pitch = this->screen->pitch;
      int row;
      int xmult = this->screen->format->BytesPerPixel;
      for (j = 0; j < numrects; j++)
      {
         from = this->hidden->bank[0] + rects->x * xmult + rects->y * pitch;
         to  = this->hidden->bank[1] + rects->x * xmult + rects->y * pitch;
         for (row = 0; row < rects->h; row++)
         {
             SDL_memcpy(to, from, rects->w * xmult);
             from += pitch;
             to += pitch;
         }
         rects++;
      }
}

/* Use optimized assembler memory copy. Deliberately copies extra columns if
   necessary to ensure the rectangle is word aligned. */
static void FULLSCREEN_UpdateRects8bpp(_THIS, int numrects, SDL_Rect *rects)
{
   int j;
   char *to, *from;
   int pitch = this->screen->pitch;
   int width_bytes;
   int src_skip_bytes;

   for (j = 0; j < numrects; j++)
   {
      from = this->hidden->bank[0] + rects->x + rects->y * pitch;
      to  = this->hidden->bank[1] + rects->x + rects->y * pitch;
      width_bytes = rects->w;
      if ((int)from & 3)
      {
         int extra = ((int)from & 3);
         from -= extra;
         to -= extra;
         width_bytes += extra;
      }
      if (width_bytes & 3) width_bytes += 4 - (width_bytes & 3);
      src_skip_bytes = pitch - width_bytes;
               
      RISCOS_Put32(to, (width_bytes >> 2), pitch, (int)rects->h, from, src_skip_bytes);
      rects++;
   }
}

/* Use optimized assembler memory copy. Deliberately copies extra columns if
   necessary to ensure the rectangle is word aligned. */
static void FULLSCREEN_UpdateRects16bpp(_THIS, int numrects, SDL_Rect *rects)
{
   int j;
   char *to, *from;
   int pitch = this->screen->pitch;
   int width_bytes;
   int src_skip_bytes;

   for (j = 0; j < numrects; j++)
   {
      from = this->hidden->bank[0] + (rects->x << 1) + rects->y * pitch;
      to  = this->hidden->bank[1] + (rects->x << 1) + rects->y * pitch;
      width_bytes = (((int)rects->w) << 1);
      if ((int)from & 3)
      {
         from -= 2;
         to -= 2;
         width_bytes += 2;
      }
      if (width_bytes & 3) width_bytes += 2;
      src_skip_bytes = pitch - width_bytes;
               
      RISCOS_Put32(to, (width_bytes >> 2), pitch, (int)rects->h, from, src_skip_bytes);
      rects++;
   }
}

/* Use optimized assembler memory copy. 32 bpp modes are always word aligned */
static void FULLSCREEN_UpdateRects32bpp(_THIS, int numrects, SDL_Rect *rects)
{
   int j;
   char *to, *from;
   int pitch = this->screen->pitch;
   int width;

   for (j = 0; j < numrects; j++)
   {
      from = this->hidden->bank[0] + (rects->x << 2) + rects->y * pitch;
      to  = this->hidden->bank[1] + (rects->x << 2) + rects->y * pitch;
      width = (int)rects->w ;
               
      RISCOS_Put32(to, width, pitch, (int)rects->h, from, pitch - (width << 2));
      rects++;
   }
}

/* Use operating system sprite plots. Currently this is much slower than the
   other variants however accelerated sprite plotting can be seen on the horizon
   so this prepares for it. */
static void FULLSCREEN_UpdateRectsOS(_THIS, int numrects, SDL_Rect *rects)
{
   _kernel_swi_regs regs;
   _kernel_oserror *err;
   int j;
   int y;

   regs.r[0] = 28 + 512;
   regs.r[1] = (unsigned int)this->hidden->alloc_bank;
   regs.r[2] = (unsigned int)this->hidden->alloc_bank+16;
   regs.r[5] = 0;

   for (j = 0; j < numrects; j++)
   {
      y = this->screen->h - rects->y; /* top of clipping region */
      _kernel_oswrch(24); /* Set graphics clip region */
      _kernel_oswrch((rects->x << this->hidden->xeig) & 0xFF); /* left */
      _kernel_oswrch(((rects->x << this->hidden->xeig) >> 8) & 0xFF);
      _kernel_oswrch(((y - rects->h) << this->hidden->yeig) & 0xFF); /* bottom */
      _kernel_oswrch((((y - rects->h) << this->hidden->yeig)>> 8) & 0xFF);
      _kernel_oswrch(((rects->x + rects->w - 1) << this->hidden->xeig) & 0xFF); /* right */
      _kernel_oswrch((((rects->x + rects->w - 1)<< this->hidden->xeig) >> 8) & 0xFF);
      _kernel_oswrch(((y-1) << this->hidden->yeig) & 0xFF); /* top */
      _kernel_oswrch((((y-1) << this->hidden->yeig) >> 8) & 0xFF);

      regs.r[3] = 0;
      regs.r[4] = 0;

      if ((err = _kernel_swi(OS_SpriteOp, &regs, &regs)) != 0)
      {
         printf("OS_SpriteOp failed \n%s\n",err->errmess);
      }

      rects++;

      /* Reset to full screen clipping */
      _kernel_oswrch(24); /* Set graphics clip region */
      _kernel_oswrch(0); /* left */
      _kernel_oswrch(0);
      _kernel_oswrch(0); /* bottom */
      _kernel_oswrch(0);
      _kernel_oswrch(((this->screen->w-1) << this->hidden->xeig) & 0xFF); /* right */
      _kernel_oswrch((((this->screen->w-1) << this->hidden->xeig) >> 8) & 0xFF);
      _kernel_oswrch(((this->screen->h-1) << this->hidden->yeig) & 0xFF); /* top */
      _kernel_oswrch((((this->screen->h-1) << this->hidden->yeig) >> 8) & 0xFF);
   }
}


int FULLSCREEN_SetColors(_THIS, int firstcolor, int ncolors, SDL_Color *colors)
{
	_kernel_swi_regs regs;
	int palette[256];

	regs.r[0] = -1;
	regs.r[1] = -1;
	regs.r[2] = (int)palette;
	regs.r[3] = 1024;
	regs.r[4] = 0;
	_kernel_swi(ColourTrans_ReadPalette, &regs, &regs);

	while(ncolors--)
	{
		palette[firstcolor] = ((colors->b) << 24) | ((colors->g) << 16) | ((colors->r) << 8);
		firstcolor++;
		colors++;
	}

	regs.r[0] = -1;
	regs.r[1] = -1;
	regs.r[2] = (int)palette;
	regs.r[3] = 0;
	regs.r[4] = 0;
	_kernel_swi(ColourTrans_WritePalette, &regs, &regs);

	return(1);
}


static int cmpmodes(const void *va, const void *vb)
{
    SDL_Rect *a = *(SDL_Rect **)va;
    SDL_Rect *b = *(SDL_Rect **)vb;
    if(a->w == b->w)
        return b->h - a->h;
    else
        return b->w - a->w;
}

static int FULLSCREEN_AddMode(_THIS, int bpp, int w, int h)
{
	SDL_Rect *mode;
	int i, index;
	int next_mode;

	/* Check to see if we already have this mode */
	if ( bpp < 8 ) {  /* Not supported */
		return(0);
	}
	index = ((bpp+7)/8)-1;
	for ( i=0; i<SDL_nummodes[index]; ++i ) {
		mode = SDL_modelist[index][i];
		if ( (mode->w == w) && (mode->h == h) ) {
			return(0);
		}
	}

	/* Set up the new video mode rectangle */
	mode = (SDL_Rect *)SDL_malloc(sizeof *mode);
	if ( mode == NULL ) {
		SDL_OutOfMemory();
		return(-1);
	}
	mode->x = 0;
	mode->y = 0;
	mode->w = w;
	mode->h = h;

	/* Allocate the new list of modes, and fill in the new mode */
	next_mode = SDL_nummodes[index];
	SDL_modelist[index] = (SDL_Rect **)
	       SDL_realloc(SDL_modelist[index], (1+next_mode+1)*sizeof(SDL_Rect *));
	if ( SDL_modelist[index] == NULL ) {
		SDL_OutOfMemory();
		SDL_nummodes[index] = 0;
		SDL_free(mode);
		return(-1);
	}
	SDL_modelist[index][next_mode] = mode;
	SDL_modelist[index][next_mode+1] = NULL;
	SDL_nummodes[index]++;

	return(0);
}

void FULLSCREEN_SetWriteBank(int bank)
{
   _kernel_swi_regs regs;
   regs.r[0] = 112;
   regs.r[1] = bank+1;
   _kernel_swi(OS_Byte, &regs, &regs);
}

void FULLSCREEN_SetDisplayBank(int bank)
{
   _kernel_swi_regs regs;
   regs.r[0] = 113;
   regs.r[1] = bank+1;
   _kernel_swi(OS_Byte, &regs, &regs);
}


/** Disable special escape key processing */
static void FULLSCREEN_DisableEscape()
{
   _kernel_swi_regs regs;
   regs.r[0] = 229;
   regs.r[1] = 1;
   regs.r[2] = 0;
   _kernel_swi(OS_Byte, &regs, &regs);
  
}

/** Enable special escape key processing */
static void FULLSCREEN_EnableEscape()
{
   _kernel_swi_regs regs;
   regs.r[0] = 229;
   regs.r[1] = 0;
   regs.r[2] = 0;
   _kernel_swi(OS_Byte, &regs, &regs);
  
}

/** Store caption in case this is called before we create a window */
void FULLSCREEN_SetWMCaption(_THIS, const char *title, const char *icon)
{
	SDL_strlcpy(this->hidden->title, title, SDL_arraysize(this->hidden->title));
}

/* Set screen mode
*
*  Returns 1 if mode is set ok, otherwise 0
*/

int FULLSCREEN_SetMode(int width, int height, int bpp)
{
   SCREENMODEBLOCK smb;
   _kernel_swi_regs regs;

   smb.flags = 1;
   smb.x_pixels = width;
   smb.y_pixels = height;
   smb.mode_vars[0] = -1;

   switch(bpp)
   {
	case 8:
		smb.pixel_depth = 3;
		/* Note: Need to set ModeFlags to 128 and NColour variables to 255 get full 8 bit palette */
		smb.mode_vars[0] = 0; smb.mode_vars[1] = 128; /* Mode flags */
		smb.mode_vars[2] = 3; smb.mode_vars[3] = 255; /* NColour (number of colours -1) */
		smb.mode_vars[4] = -1; /* End of list */
		break;

	case 15:
	case 16:
		smb.pixel_depth = 4;
		break;

	case 32:
		smb.pixel_depth = 5;
		break;

	default:
		SDL_SetError("Pixel depth not supported");
		return 0;
		break;
   }
   
   smb.frame_rate = -1;

   regs.r[0] = 0;
   regs.r[1] = (int)&smb;

   if (_kernel_swi(OS_ScreenMode, &regs, &regs) != 0)
   {
	   SDL_SetError("Couldn't set requested mode");
	   return 0;
   }

    /* Turn cursor off*/
    _kernel_oswrch(23);_kernel_oswrch(1);_kernel_oswrch(0);
    _kernel_oswrch(0);_kernel_oswrch(0);_kernel_oswrch(0);
    _kernel_oswrch(0);_kernel_oswrch(0);_kernel_oswrch(0);
    _kernel_oswrch(0);_kernel_oswrch(0);

   return 1;
}

/* Get Start addresses for the screen banks */
void FULLSCREEN_SetupBanks(_THIS)
{
   _kernel_swi_regs regs;
   int block[5];
   block[0] = 148; /* Write screen start */
   block[1] = 149; /* Display screen start */
   block[2] = 4;  /* X eig factor */
   block[3] = 5;  /* Y eig factor */
   block[4] = -1;  /* End of list of variables to request */

   regs.r[0] = (int)block;
   regs.r[1] = (int)block;
   _kernel_swi(OS_ReadVduVariables, &regs, &regs);

   this->hidden->bank[0] = (void *)block[0];
   this->hidden->bank[1] = (void *)block[1];
   this->hidden->xeig = block[2];
   this->hidden->yeig = block[3];
}

/* Toggle to full screen mode from the WIMP */

int FULLSCREEN_ToggleFromWimp(_THIS)
{
   int width = this->screen->w;
   int height = this->screen->h;
   int bpp = this->screen->format->BitsPerPixel;

   RISCOS_StoreWimpMode();
   if (FULLSCREEN_SetMode(width, height, bpp))
   {
       char *buffer = this->hidden->alloc_bank; /* This is start of sprite data */
       /* Support back buffer mode only */
       if (riscos_backbuffer == 0) riscos_backbuffer = 1;

       FULLSCREEN_SetupBanks(this);

       this->hidden->bank[0] = buffer + 60; /* Start of sprite data */
       if (bpp == 8) this->hidden->bank[0] += 2048; /* 8bpp sprite have palette first */

	   this->hidden->current_bank = 0;
	   this->screen->pixels = this->hidden->bank[0];

       /* Copy back buffer to screen memory */
       SDL_memcpy(this->hidden->bank[1], this->hidden->bank[0], width * height * this->screen->format->BytesPerPixel);

       FULLSCREEN_SetDeviceMode(this);
       return 1;
   } else
      RISCOS_RestoreWimpMode();

   return 0;
}