/*

    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 Sprite plotting code for wimp display.window

*/

#include "kernel.h"

#include "swis.h"

#include "SDL_stdinc.h"

#include "SDL_riscosvideo.h"

extern void WIMP_ReadModeInfo(_THIS);

void WIMP_PaletteChanged(_THIS);

/* Create sprite buffer for screen */

unsigned char *WIMP_CreateBuffer(int width, int height, int bpp)

{

	int size;

	char sprite_name[12] = "display";

	unsigned char *buffer;

	_kernel_swi_regs regs;

	int bytesPerPixel;

	int bytesPerRow;

	int offsetToSpriteData = 60;

	switch(bpp)

	{

	case 32: bytesPerPixel = 4; break;

	case 16: bytesPerPixel = 2; break;

	case 8:

	    bytesPerPixel = 1;

	    offsetToSpriteData += 2048; /* Add in size of palette */

	    break;

	default:

		return NULL;

		break;

	}

	bytesPerRow = bytesPerPixel * width;

	if ((bytesPerRow & 3) != 0)

	{

		bytesPerRow += 4 - (bytesPerRow & 3);

	}

	size = bytesPerRow * height;

	buffer = SDL_malloc( (size_t) size + offsetToSpriteData );

	if (!buffer) return NULL;

   /* Initialise a sprite area */

	*(unsigned int *)buffer		= size + offsetToSpriteData;

	*(unsigned int *)(buffer + 8)	= 16;

	regs.r[0] = 256+9;

	regs.r[1] = (unsigned int)buffer;

   _kernel_swi(OS_SpriteOp, &regs, &regs);

	regs.r[0] = 256+15;

	regs.r[1] = (unsigned int)buffer;

	regs.r[2] = (unsigned int)&sprite_name;

	regs.r[3] = 0; /* Palette flag: 0 = no palette */

	regs.r[4] = width;

	regs.r[5] = height;

	if (bpp == 8)

	{

		/* Use old style mode number */

		regs.r[6] = 28; /* 8bpp 90x90dpi */

	} else

	{

		regs.r[6] = (((bpp == 16) ? 5 : 6) << 27) /* Type 6 = 32bpp sprite, 5 = 16bpp sprite */

					| (90 << 14) /* Vertical dpi */

					| (90 << 1)  /* Horizontal dpi */

					| 1; /* Marker to distinguish between mode selectors and sprite modes */

	}

   if (_kernel_swi(OS_SpriteOp, &regs, &regs) == NULL)

   {

       if (bpp == 8)

       {

          /* Modify sprite to take into account 256 colour palette */

          int *sprite = (int *)(buffer + 16);

          /* Adjust sprite offsets */

          sprite[0] += 2048;

          sprite[8] += 2048;

          sprite[9] += 2048;

          /* Adjust sprite area next free pointer */

          (*(int *)(buffer+12)) += 2048;

          /* Don't need to set up palette as SDL sets up the default

             256 colour palette */

/*          {

             int *pal = sprite + 11;

             unsigned int j;

             unsigned int entry;

             for (j = 0; j < 255; j++)

             {

                entry = (j << 24) | (j << 16) | (j << 8);

                *pal++ = entry;

                *pal++ = entry;

             }

          }

*/

       }

   } else

   {

      SDL_free(buffer);

      buffer = NULL;

   }

   return buffer;

}

/* Setup translation buffers for the sprite plotting */

void WIMP_SetupPlotInfo(_THIS)

{

   _kernel_swi_regs regs;

   int *sprite = ((int *)this->hidden->bank[1])+4;

   regs.r[0] = (unsigned int)this->hidden->bank[1];

   regs.r[1] = (unsigned int)sprite;

   regs.r[2] = -1; /* Current mode */

   regs.r[3] = -1; /* Current palette */

   regs.r[4] = 0; /* Get size of buffer */

   regs.r[5] = 1|2|16; /* R1 - pointer to sprite and can use full palette words */

   regs.r[6] = 0;

   regs.r[7] = 0;

   if (this->hidden->pixtrans) SDL_free(this->hidden->pixtrans);

   this->hidden->pixtrans = 0;

   /* Get the size required for the buffer */

   _kernel_swi(ColourTrans_GenerateTable, &regs, &regs);

   if (regs.r[4])

   {

      this->hidden->pixtrans = SDL_malloc(regs.r[4]);

      regs.r[4] = (unsigned int)this->hidden->pixtrans;

      /* Actually read the buffer */

      _kernel_swi(ColourTrans_GenerateTable, &regs, &regs);

   }

}

/* Plot the sprite in the given context */

void WIMP_PlotSprite(_THIS, int x, int y)

{

   _kernel_swi_regs regs;

   _kernel_oserror *err;

   regs.r[0] =  52 + 512;

   regs.r[1] = (unsigned int)this->hidden->bank[1];

   regs.r[2] = (unsigned int)this->hidden->bank[1]+16;

   regs.r[3] = x;

   regs.r[4] = y;

   regs.r[5] = 0|32; /* Overwrite screen and pixtrans contains wide colour entries */

   regs.r[6] = 0; /* No scale factors i.e. 1:1 */

   regs.r[7] = (int)this->hidden->pixtrans;

   if ((err = _kernel_swi(OS_SpriteOp, &regs, &regs)) != 0)

   {

      int *p = (int *)this->hidden->pixtrans;

      printf("OS_SpriteOp failed \n%s\n",err->errmess);

      printf("pixtrans %d\n", (int)this->hidden->pixtrans);

      printf("%x %x %x\n", p[0], p[1], p[2]);

   }

}

/* Wimp mode has changes so update colour mapping and pixel sizes 

   of windows and the sprites they plot */

void WIMP_ModeChanged(_THIS)

{

	int oldXeig = this->hidden->xeig;

	int oldYeig = this->hidden->yeig;

	WIMP_ReadModeInfo(this);

	if (oldXeig == this->hidden->xeig && oldYeig == this->hidden->yeig)

	{

		/* Only need to update the palette */

		WIMP_PaletteChanged(this);

	} else

	{

		_kernel_swi_regs regs;

		int window_state[9];

		int extent[4];

		int currWidth, currHeight;

		int newWidth, newHeight;

		/* Need to resize windows and update the palette */

		WIMP_SetupPlotInfo(this);

		window_state[0] = this->hidden->window_handle;

		regs.r[1] = (unsigned int)window_state;

		_kernel_swi(Wimp_GetWindowState, &regs, &regs);

		currWidth = window_state[3] - window_state[1];

		currHeight = window_state[4] - window_state[2];

		newWidth = (currWidth >> oldXeig) << this->hidden->xeig;

		newHeight = (currHeight >> oldYeig) << this->hidden->yeig;

		/* Need to avoid extent getting too small for visible part

		of window */

		extent[0] = 0;

		if (currHeight <= newHeight)

		{

			extent[1] = -newHeight;

		} else

		{

			extent[1] = -currHeight;

		}

		if (currWidth <= newWidth)

		{

			extent[2] = newWidth;

		} else

		{

			extent[2] = currWidth;

		}

		extent[3] = 0;

		regs.r[0] = this->hidden->window_handle;

		regs.r[1] = (int)extent;

		_kernel_swi(Wimp_SetExtent, &regs, &regs);

		/*TODO: May need to set flag to resize window on next open */

	}

}

/* Palette has changed so update palettes used for windows sprites */

void WIMP_PaletteChanged(_THIS)

{

	WIMP_SetupPlotInfo(this);

}