/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  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

*/

#ifdef SAVE_RCSID

static char rcsid =

 "@(#) $Id$";

#endif

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "SDL_error.h"

#include "SDL_video.h"

#include "SDL_sysvideo.h"

#include "SDL_blit.h"

#include "SDL_RLEaccel_c.h"

#include "SDL_pixels_c.h"

#include "SDL_memops.h"

/* The general purpose software blit routine */

static int SDL_SoftBlit(SDL_Surface *src, SDL_Rect *srcrect,

			SDL_Surface *dst, SDL_Rect *dstrect)

{

	int okay;

	int src_locked;

	int dst_locked;

	/* Everything is okay at the beginning...  */

	okay = 1;

	/* Lock the destination if it's in hardware */

	dst_locked = 0;

	if ( dst->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {

		SDL_VideoDevice *video = current_video;

		SDL_VideoDevice *this  = current_video;

		if ( video->LockHWSurface(this, dst) < 0 ) {

			okay = 0;

		} else {

			dst_locked = 1;

		}

	}

	/* Lock the source if it's in hardware */

	src_locked = 0;

	if ( src->flags & (SDL_HWSURFACE|SDL_ASYNCBLIT) ) {

		SDL_VideoDevice *video = current_video;

		SDL_VideoDevice *this  = current_video;

		if ( video->LockHWSurface(this, src) < 0 ) {

			okay = 0;

		} else {

			src_locked = 1;

		}

	}

	/* Unencode the destination if it's RLE encoded */

	if ( dst->flags & SDL_RLEACCEL ) {

		SDL_UnRLESurface(dst, 1);

		dst->flags |= SDL_RLEACCEL;	/* save accel'd state */

	}

	/* Set up source and destination buffer pointers, and BLIT! */

	if ( okay  && srcrect->w && srcrect->h ) {

		SDL_BlitInfo info;

		SDL_loblit RunBlit;

		/* Set up the blit information */

		info.s_pixels = (Uint8 *)src->pixels + src->offset +

				(Uint16)srcrect->y*src->pitch +

				(Uint16)srcrect->x*src->format->BytesPerPixel;

		info.s_width = srcrect->w;

		info.s_height = srcrect->h;

		info.s_skip=src->pitch-info.s_width*src->format->BytesPerPixel;

		info.d_pixels = (Uint8 *)dst->pixels + dst->offset +

				(Uint16)dstrect->y*dst->pitch +

				(Uint16)dstrect->x*dst->format->BytesPerPixel;

		info.d_width = dstrect->w;

		info.d_height = dstrect->h;

		info.d_skip=dst->pitch-info.d_width*dst->format->BytesPerPixel;

		info.aux_data = src->map->sw_data->aux_data;

		info.src = src->format;

		info.table = src->map->table;

		info.dst = dst->format;

		RunBlit = src->map->sw_data->blit;

		/* Run the actual software blit */

		RunBlit(&info);

	}

	/* Re-encode the destination if it's RLE encoded */

	if ( dst->flags & SDL_RLEACCEL ) {

	        dst->flags &= ~SDL_RLEACCEL; /* stop lying */

		SDL_RLESurface(dst);

	}

	/* We need to unlock the surfaces if they're locked */

	if ( dst_locked ) {

		SDL_VideoDevice *video = current_video;

		SDL_VideoDevice *this  = current_video;

		video->UnlockHWSurface(this, dst);

	} else

	if ( src_locked ) {

		SDL_VideoDevice *video = current_video;

		SDL_VideoDevice *this  = current_video;

		video->UnlockHWSurface(this, src);

	}

	/* Blit is done! */

	return(okay ? 0 : -1);

}

static void SDL_BlitCopy(SDL_BlitInfo *info)

{

	Uint8 *src, *dst;

	int w, h;

	int srcskip, dstskip;

	w = info->d_width*info->dst->BytesPerPixel;

	h = info->d_height;

	src = info->s_pixels;

	dst = info->d_pixels;

	srcskip = w+info->s_skip;

	dstskip = w+info->d_skip;

	while ( h-- ) {

		SDL_memcpy(dst, src, w);

		src += srcskip;

		dst += dstskip;

	}

}

static void SDL_BlitCopyOverlap(SDL_BlitInfo *info)

{

	Uint8 *src, *dst;

	int w, h;

	int srcskip, dstskip;

	w = info->d_width*info->dst->BytesPerPixel;

	h = info->d_height;

	src = info->s_pixels;

	dst = info->d_pixels;

	srcskip = w+info->s_skip;

	dstskip = w+info->d_skip;

	if ( dst < src ) {

		while ( h-- ) {

			SDL_memcpy(dst, src, w);

			src += srcskip;

			dst += dstskip;

		}

	} else {

		src += ((h-1) * srcskip);

		dst += ((h-1) * dstskip);

		while ( h-- ) {

			SDL_revcpy(dst, src, w);

			src -= srcskip;

			dst -= dstskip;

		}

	}

}

/* Figure out which of many blit routines to set up on a surface */

int SDL_CalculateBlit(SDL_Surface *surface)

{

	int blit_index;

	/* Clean everything out to start */

	if ( (surface->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {

		SDL_UnRLESurface(surface, 1);

	}

	surface->map->sw_blit = NULL;

	/* Figure out if an accelerated hardware blit is possible */

	surface->flags &= ~SDL_HWACCEL;

	if ( surface->map->identity ) {

		int hw_blit_ok;

		if ( (surface->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {

			/* We only support accelerated blitting to hardware */

			if ( surface->map->dst->flags & SDL_HWSURFACE ) {

				hw_blit_ok = current_video->info.blit_hw;

			} else {

				hw_blit_ok = 0;

			}

			if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {

				hw_blit_ok = current_video->info.blit_hw_CC;

			}

			if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {

				hw_blit_ok = current_video->info.blit_hw_A;

			}

		} else {

			/* We only support accelerated blitting to hardware */

			if ( surface->map->dst->flags & SDL_HWSURFACE ) {

				hw_blit_ok = current_video->info.blit_sw;

			} else {

				hw_blit_ok = 0;

			}

			if (hw_blit_ok && (surface->flags & SDL_SRCCOLORKEY)) {

				hw_blit_ok = current_video->info.blit_sw_CC;

			}

			if ( hw_blit_ok && (surface->flags & SDL_SRCALPHA) ) {

				hw_blit_ok = current_video->info.blit_sw_A;

			}

		}

		if ( hw_blit_ok ) {

			SDL_VideoDevice *video = current_video;

			SDL_VideoDevice *this  = current_video;

			video->CheckHWBlit(this, surface, surface->map->dst);

		}

	}

	/* Get the blit function index, based on surface mode */

	/* { 0 = nothing, 1 = colorkey, 2 = alpha, 3 = colorkey+alpha } */

	blit_index = 0;

	blit_index |= (!!(surface->flags & SDL_SRCCOLORKEY))      << 0;

	if ( surface->flags & SDL_SRCALPHA

	     && (surface->format->alpha != SDL_ALPHA_OPAQUE

		 || surface->format->Amask) ) {

	        blit_index |= 2;

	}

	/* Check for special "identity" case -- copy blit */

	if ( surface->map->identity && blit_index == 0 ) {

	        surface->map->sw_data->blit = SDL_BlitCopy;

		/* Handle overlapping blits on the same surface */

		if ( surface == surface->map->dst ) {

		        surface->map->sw_data->blit = SDL_BlitCopyOverlap;

		}

	} else {

		if ( surface->format->BitsPerPixel < 8 ) {

			surface->map->sw_data->blit =

			    SDL_CalculateBlit0(surface, blit_index);

		} else {

			switch ( surface->format->BytesPerPixel ) {

			    case 1:

				surface->map->sw_data->blit =

				    SDL_CalculateBlit1(surface, blit_index);

				break;

			    case 2:

			    case 3:

			    case 4:

				surface->map->sw_data->blit =

				    SDL_CalculateBlitN(surface, blit_index);

				break;

			    default:

				surface->map->sw_data->blit = NULL;

				break;

			}

		}

	}

	/* Make sure we have a blit function */

	if ( surface->map->sw_data->blit == NULL ) {

		SDL_InvalidateMap(surface->map);

		SDL_SetError("Blit combination not supported");

		return(-1);

	}

	/* Choose software blitting function */

	if(surface->flags & SDL_RLEACCELOK

	   && (surface->flags & SDL_HWACCEL) != SDL_HWACCEL) {

	        if(surface->map->identity

		   && (blit_index == 1

		       || (blit_index == 3 && !surface->format->Amask))) {

		        if ( SDL_RLESurface(surface) == 0 )

			        surface->map->sw_blit = SDL_RLEBlit;

		} else if(blit_index == 2 && surface->format->Amask) {

		        if ( SDL_RLESurface(surface) == 0 )

			        surface->map->sw_blit = SDL_RLEAlphaBlit;

		}

	}

	if ( surface->map->sw_blit == NULL ) {

		surface->map->sw_blit = SDL_SoftBlit;

	}

	return(0);

}