/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include "SDL_video.h"

#include "SDL_sysvideo.h"

#include "SDL_cursor_c.h"

#include "SDL_blit.h"

#include "SDL_RLEaccel_c.h"

#include "SDL_pixels_c.h"

#include "SDL_leaks.h"

/* Public routines */

/*

 * Create an empty RGB surface of the appropriate depth

 */

SDL_Surface * SDL_CreateRGBSurface (Uint32 flags,

			int width, int height, int depth,

			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)

{

	SDL_VideoDevice *video = current_video;

	SDL_VideoDevice *this  = current_video;

	SDL_Surface *screen;

	SDL_Surface *surface;

	/* Make sure the size requested doesn't overflow our datatypes */

	/* Next time I write a library like SDL, I'll use int for size. :) */

	if ( width >= 16384 || height >= 65536 ) {

		SDL_SetError("Width or height is too large");

		return(NULL);

	}

	/* Check to see if we desire the surface in video memory */

	if ( video ) {

		screen = SDL_PublicSurface;

	} else {

		screen = NULL;

	}

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

		if ( (flags&(SDL_SRCCOLORKEY|SDL_SRCALPHA)) != 0 ) {

			flags |= SDL_HWSURFACE;

		}

		if ( (flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY ) {

			if ( ! current_video->info.blit_hw_CC ) {

				flags &= ~SDL_HWSURFACE;

			}

		}

		if ( (flags & SDL_SRCALPHA) == SDL_SRCALPHA ) {

			if ( ! current_video->info.blit_hw_A ) {

				flags &= ~SDL_HWSURFACE;

			}

		}

	} else {

		flags &= ~SDL_HWSURFACE;

	}

	/* Allocate the surface */

	surface = (SDL_Surface *)SDL_malloc(sizeof(*surface));

	if ( surface == NULL ) {

		SDL_OutOfMemory();

		return(NULL);

	}

	surface->flags = SDL_SWSURFACE;

	if ( (flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {

		if ((Amask) && (video->displayformatalphapixel))

		{

			depth = video->displayformatalphapixel->BitsPerPixel;

			Rmask = video->displayformatalphapixel->Rmask;

			Gmask = video->displayformatalphapixel->Gmask;

			Bmask = video->displayformatalphapixel->Bmask;

			Amask = video->displayformatalphapixel->Amask;

		}

		else

		{

			depth = screen->format->BitsPerPixel;

			Rmask = screen->format->Rmask;

			Gmask = screen->format->Gmask;

			Bmask = screen->format->Bmask;

			Amask = screen->format->Amask;

		}

	}

	surface->format = SDL_AllocFormat(depth, Rmask, Gmask, Bmask, Amask);

	if ( surface->format == NULL ) {

		SDL_free(surface);

		return(NULL);

	}

	if ( Amask ) {

		surface->flags |= SDL_SRCALPHA;

	}

	surface->w = width;

	surface->h = height;

	surface->pitch = SDL_CalculatePitch(surface);

	surface->pixels = NULL;

	surface->offset = 0;

	surface->hwdata = NULL;

	surface->locked = 0;

	surface->map = NULL;

	surface->unused1 = 0;

	SDL_SetClipRect(surface, NULL);

	SDL_FormatChanged(surface);

	/* Get the pixels */

	if ( ((flags&SDL_HWSURFACE) == SDL_SWSURFACE) || 

				(video->AllocHWSurface(this, surface) < 0) ) {

		if ( surface->w && surface->h ) {

			surface->pixels = SDL_malloc(surface->h*surface->pitch);

			if ( surface->pixels == NULL ) {

				SDL_FreeSurface(surface);

				SDL_OutOfMemory();

				return(NULL);

			}

			/* This is important for bitmaps */

			SDL_memset(surface->pixels, 0, surface->h*surface->pitch);

		}

	}

	/* Allocate an empty mapping */

	surface->map = SDL_AllocBlitMap();

	if ( surface->map == NULL ) {

		SDL_FreeSurface(surface);

		return(NULL);

	}

	/* The surface is ready to go */

	surface->refcount = 1;

#ifdef CHECK_LEAKS

	++surfaces_allocated;

#endif

	return(surface);

}

/*

 * Create an RGB surface from an existing memory buffer

 */

SDL_Surface * SDL_CreateRGBSurfaceFrom (void *pixels,

			int width, int height, int depth, int pitch,

			Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask)

{

	SDL_Surface *surface;

	surface = SDL_CreateRGBSurface(SDL_SWSURFACE, 0, 0, depth,

	                               Rmask, Gmask, Bmask, Amask);

	if ( surface != NULL ) {

		surface->flags |= SDL_PREALLOC;

		surface->pixels = pixels;

		surface->w = width;

		surface->h = height;

		surface->pitch = pitch;

		SDL_SetClipRect(surface, NULL);

	}

	return(surface);

}

/*

 * 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);

}

/* 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);

}

int SDL_SetAlphaChannel(SDL_Surface *surface, Uint8 value)

{

	int row, col;

	int offset;

	Uint8 *buf;

	if ( (surface->format->Amask != 0xFF000000) &&

	     (surface->format->Amask != 0x000000FF) ) {

		SDL_SetError("Unsupported surface alpha mask format");

		return -1;

	}

#if SDL_BYTEORDER == SDL_LIL_ENDIAN

	if ( surface->format->Amask == 0xFF000000 ) {

			offset = 3;

	} else {

			offset = 0;

	}

#else

	if ( surface->format->Amask == 0xFF000000 ) {

			offset = 0;

	} else {

			offset = 3;

	}

#endif /* Byte ordering */

	/* Quickly set the alpha channel of an RGBA or ARGB surface */

	if ( SDL_MUSTLOCK(surface) ) {

		if ( SDL_LockSurface(surface) < 0 ) {

			return -1;

		}

	}

	row = surface->h;

	while (row--) {

		col = surface->w;

		buf = (Uint8 *)surface->pixels + row * surface->pitch + offset;

		while(col--) {

			*buf = value;

			buf += 4;

		}

	}

	if ( SDL_MUSTLOCK(surface) ) {

		SDL_UnlockSurface(surface);

	}

	return 0;

}

/*

 * A function to calculate the intersection of two rectangles:

 * return true if the rectangles intersect, false otherwise

 */

static __inline__

SDL_bool SDL_IntersectRect(const SDL_Rect *A, const SDL_Rect *B, SDL_Rect *intersection)

{

	int Amin, Amax, Bmin, Bmax;

	/* Horizontal intersection */

	Amin = A->x;

	Amax = Amin + A->w;

	Bmin = B->x;

	Bmax = Bmin + B->w;

	if(Bmin > Amin)

	        Amin = Bmin;

	intersection->x = Amin;

	if(Bmax < Amax)

	        Amax = Bmax;

	intersection->w = Amax - Amin > 0 ? Amax - Amin : 0;

	/* Vertical intersection */

	Amin = A->y;

	Amax = Amin + A->h;

	Bmin = B->y;

	Bmax = Bmin + B->h;

	if(Bmin > Amin)

	        Amin = Bmin;

	intersection->y = Amin;

	if(Bmax < Amax)

	        Amax = Bmax;

	intersection->h = Amax - Amin > 0 ? Amax - Amin : 0;

	return (intersection->w && intersection->h);

}

/*

 * Set the clipping rectangle for a blittable surface

 */

SDL_bool SDL_SetClipRect(SDL_Surface *surface, const SDL_Rect *rect)

{

	SDL_Rect full_rect;

	/* Don't do anything if there's no surface to act on */

	if ( ! surface ) {

		return SDL_FALSE;

	}

	/* Set up the full surface rectangle */

	full_rect.x = 0;

	full_rect.y = 0;

	full_rect.w = surface->w;

	full_rect.h = surface->h;

	/* Set the clipping rectangle */

	if ( ! rect ) {

		surface->clip_rect = full_rect;

		return 1;

	}

	return SDL_IntersectRect(rect, &full_rect, &surface->clip_rect);

}

void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect)

{

	if ( surface && rect ) {

		*rect = surface->clip_rect;

	}

}

/* 

 * Set up a blit between two surfaces -- split into three parts:

 * The upper part, SDL_UpperBlit(), performs clipping and rectangle 

 * verification.  The lower part is a pointer to a low level

 * accelerated blitting function.

 *

 * These parts are separated out and each used internally by this 

 * library in the optimimum places.  They are exported so that if

 * you know exactly what you are doing, you can optimize your code

 * by calling the one(s) you need.

 */

int SDL_LowerBlit (SDL_Surface *src, SDL_Rect *srcrect,

				SDL_Surface *dst, SDL_Rect *dstrect)

{

	SDL_blit do_blit;

	SDL_Rect hw_srcrect;

	SDL_Rect hw_dstrect;

	/* Check to make sure the blit mapping is valid */

	if ( (src->map->dst != dst) ||

             (src->map->dst->format_version != src->map->format_version) ) {

		if ( SDL_MapSurface(src, dst) < 0 ) {

			return(-1);

		}

	}

	/* Figure out which blitter to use */

	if ( (src->flags & SDL_HWACCEL) == SDL_HWACCEL ) {

		if ( src == SDL_VideoSurface ) {

			hw_srcrect = *srcrect;

			hw_srcrect.x += current_video->offset_x;

			hw_srcrect.y += current_video->offset_y;

			srcrect = &hw_srcrect;

		}

		if ( dst == SDL_VideoSurface ) {

			hw_dstrect = *dstrect;

			hw_dstrect.x += current_video->offset_x;

			hw_dstrect.y += current_video->offset_y;

			dstrect = &hw_dstrect;

		}

		do_blit = src->map->hw_blit;

	} else {

		do_blit = src->map->sw_blit;

	}

	return(do_blit(src, srcrect, dst, dstrect));

}

int SDL_UpperBlit (SDL_Surface *src, SDL_Rect *srcrect,

		   SDL_Surface *dst, SDL_Rect *dstrect)

{

        SDL_Rect fulldst;

	int srcx, srcy, w, h;

	/* Make sure the surfaces aren't locked */

	if ( ! src || ! dst ) {

		SDL_SetError("SDL_UpperBlit: passed a NULL surface");

		return(-1);

	}

	if ( src->locked || dst->locked ) {

		SDL_SetError("Surfaces must not be locked during blit");

		return(-1);

	}

	/* If the destination rectangle is NULL, use the entire dest surface */

	if ( dstrect == NULL ) {

	        fulldst.x = fulldst.y = 0;

		dstrect = &fulldst;

	}

	/* clip the source rectangle to the source surface */

	if(srcrect) {

	        int maxw, maxh;

		srcx = srcrect->x;

		w = srcrect->w;

		if(srcx < 0) {

		        w += srcx;

			dstrect->x -= srcx;

			srcx = 0;

		}

		maxw = src->w - srcx;

		if(maxw < w)

			w = maxw;

		srcy = srcrect->y;

		h = srcrect->h;

		if(srcy < 0) {

		        h += srcy;

			dstrect->y -= srcy;

			srcy = 0;

		}

		maxh = src->h - srcy;

		if(maxh < h)

			h = maxh;

	} else {

	        srcx = srcy = 0;

		w = src->w;

		h = src->h;

	}

	/* clip the destination rectangle against the clip rectangle */

	{

	        SDL_Rect *clip = &dst->clip_rect;

		int dx, dy;

		dx = clip->x - dstrect->x;

		if(dx > 0) {

			w -= dx;

			dstrect->x += dx;

			srcx += dx;

		}

		dx = dstrect->x + w - clip->x - clip->w;

		if(dx > 0)

			w -= dx;

		dy = clip->y - dstrect->y;

		if(dy > 0) {

			h -= dy;

			dstrect->y += dy;

			srcy += dy;

		}

		dy = dstrect->y + h - clip->y - clip->h;

		if(dy > 0)

			h -= dy;

	}

	if(w > 0 && h > 0) {

	        SDL_Rect sr;

	        sr.x = srcx;

		sr.y = srcy;

		sr.w = dstrect->w = w;