/*

    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_compat.h"

#include "SDL_sysvideo.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_Surface *surface;

    /* Allocate the surface */

    surface = (SDL_Surface *) SDL_calloc(1, sizeof(*surface));

    if (surface == NULL) {

        SDL_OutOfMemory();

        return NULL;

    }

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

    if (!surface->format) {

        SDL_FreeSurface(surface);

        return NULL;

    }

    if (Amask) {

        surface->flags |= SDL_SRCALPHA;

    }

    surface->w = width;

    surface->h = height;

    surface->pitch = SDL_CalculatePitch(surface);

    SDL_SetClipRect(surface, NULL);

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

        SDL_Palette *palette =

            SDL_AllocPalette((1 << surface->format->BitsPerPixel));

        if (!palette) {

            SDL_FreeSurface(surface);

            return NULL;

        }

        if (Rmask || Bmask || Gmask) {

            const SDL_PixelFormat *format = surface->format;

            /* create palette according to masks */

            int i;

            int Rm = 0, Gm = 0, Bm = 0;

            int Rw = 0, Gw = 0, Bw = 0;

            if (Rmask) {

                Rw = 8 - format->Rloss;

                for (i = format->Rloss; i > 0; i -= Rw)

                    Rm |= 1 << i;

            }

            if (Gmask) {

                Gw = 8 - format->Gloss;

                for (i = format->Gloss; i > 0; i -= Gw)

                    Gm |= 1 << i;

            }

            if (Bmask) {

                Bw = 8 - format->Bloss;

                for (i = format->Bloss; i > 0; i -= Bw)

                    Bm |= 1 << i;

            }

            for (i = 0; i < palette->ncolors; ++i) {

                int r, g, b;

                r = (i & Rmask) >> format->Rshift;

                r = (r << format->Rloss) | ((r * Rm) >> Rw);

                palette->colors[i].r = r;

                g = (i & Gmask) >> format->Gshift;

                g = (g << format->Gloss) | ((g * Gm) >> Gw);

                palette->colors[i].g = g;

                b = (i & Bmask) >> format->Bshift;

                b = (b << format->Bloss) | ((b * Bm) >> Bw);

                palette->colors[i].b = b;

            }

        } else if (palette->ncolors == 2) {

            /* Create a black and white bitmap palette */

            palette->colors[0].r = 0xFF;

            palette->colors[0].g = 0xFF;

            palette->colors[0].b = 0xFF;

            palette->colors[1].r = 0x00;

            palette->colors[1].g = 0x00;

            palette->colors[1].b = 0x00;

        }

        SDL_SetSurfacePalette(surface, palette);

        SDL_FreePalette(palette);

    }

    /* Get the pixels */

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

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

        if (!surface->pixels) {

            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) {

        SDL_FreeSurface(surface);

        return NULL;

    }

    SDL_FormatChanged(surface);

    /* 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(0, 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;

}

SDL_Surface *

SDL_CreateRGBSurfaceFromTexture(SDL_TextureID textureID)

{

    SDL_Surface *surface;

    Uint32 format;

    int w, h;

    int bpp;

    Uint32 Rmask, Gmask, Bmask, Amask;

    void *pixels;

    int pitch;

    if (SDL_QueryTexture(textureID, &format, NULL, &w, &h) < 0) {

        return NULL;

    }

    if (!SDL_PixelFormatEnumToMasks

        (format, &bpp, &Rmask, &Gmask, &Bmask, &Amask)) {

        SDL_SetError("Unknown texture format");

        return NULL;

    }

    if (SDL_QueryTexturePixels(textureID, &pixels, &pitch) == 0) {

        surface =

            SDL_CreateRGBSurfaceFrom(pixels, w, h, bpp, pitch, Rmask, Gmask,

                                     Bmask, Amask);

    } else {

        surface =

            SDL_CreateRGBSurface(0, 0, 0, bpp, Rmask, Gmask, Bmask, Amask);

        if (surface) {

            surface->flags |= SDL_HWSURFACE;

            surface->w = w;

            surface->h = h;

            surface->pitch = SDL_CalculatePitch(surface);

            SDL_SetClipRect(surface, NULL);

        }

    }

    if (surface) {

        surface->textureID = textureID;

    }

    return surface;

}

static int

SDL_SurfacePaletteChanged(void *userdata, SDL_Palette * palette)

{

    SDL_Surface *surface = (SDL_Surface *) userdata;

    if (surface->textureID) {

        if (SDL_SetTexturePalette

            (surface->textureID, palette->colors, 0, palette->ncolors) < 0) {

            SDL_GetTexturePalette(surface->textureID, palette->colors, 0,

                                  palette->ncolors);

            return -1;

        }

    }

    SDL_FormatChanged(surface);

    return 0;

}

int

SDL_SetSurfacePalette(SDL_Surface * surface, SDL_Palette * palette)

{

    if (!surface || !surface->format) {

        SDL_SetError("SDL_SetSurfacePalette() passed a NULL surface");

        return -1;

    }

    if (palette && palette->ncolors != (1 << surface->format->BitsPerPixel)) {

        SDL_SetError

            ("SDL_SetSurfacePalette() passed a palette that doesn't match the surface format");

        return -1;

    }

    if (surface->format->palette == palette) {

        return 0;

    }

    if (surface->format->palette) {

        SDL_DelPaletteWatch(surface->format->palette,

                            SDL_SurfacePaletteChanged, surface);

    }

    surface->format->palette = palette;

    if (surface->format->palette) {

        SDL_AddPaletteWatch(surface->format->palette,

                            SDL_SurfacePaletteChanged, surface);

    }

    return 0;

}

/*

 * 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) {

        surface->flags |= SDL_SRCCOLORKEY;

        surface->format->colorkey = key;

        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) {

        surface->flags |= SDL_SRCALPHA;

        surface->format->alpha = value;

        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 (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;

}

/*

 * 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)

{

    /* 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);

        }

    }

    return (src->map->sw_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;

        sr.h = dstrect->h = h;

        return SDL_LowerBlit(src, &sr, dst, dstrect);

    }

    dstrect->w = dstrect->h = 0;

    return 0;

}

static int

SDL_FillRect1(SDL_Surface * dst, SDL_Rect * dstrect, Uint32 color)

{

    /* FIXME: We have to worry about packing order.. *sigh* */

    SDL_SetError("1-bpp rect fill not yet implemented");

    return -1;

}

static int

SDL_FillRect4(SDL_Surface * dst, SDL_Rect * dstrect, Uint32 color)

{

    /* FIXME: We have to worry about packing order.. *sigh* */

    SDL_SetError("4-bpp rect fill not yet implemented");

    return -1;

}

/* 

 * This function performs a fast fill of the given rectangle with 'color'

 */

int

SDL_FillRect(SDL_Surface * dst, SDL_Rect * dstrect, Uint32 color)

{

    int x, y;

    Uint8 *row;

    /* This function doesn't work on surfaces < 8 bpp */

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

        switch (dst->format->BitsPerPixel) {

        case 1:

            return SDL_FillRect1(dst, dstrect, color);

            break;

        case 4:

            return SDL_FillRect4(dst, dstrect, color);

            break;

        default:

            SDL_SetError("Fill rect on unsupported surface format");

            return (-1);

            break;

        }

    }

    /* If 'dstrect' == NULL, then fill the whole surface */

    if (dstrect) {

        /* Perform clipping */

        if (!SDL_IntersectRect(dstrect, &dst->clip_rect, dstrect)) {

            return (0);

        }

    } else {

        dstrect = &dst->clip_rect;

    }

    /* Perform software fill */

    if (SDL_LockSurface(dst) != 0) {

        return (-1);

    }

    row = (Uint8 *) dst->pixels + dstrect->y * dst->pitch +

        dstrect->x * dst->format->BytesPerPixel;

    if (dst->format->palette || (color == 0)) {

        x = dstrect->w * dst->format->BytesPerPixel;

        if (!color && !((uintptr_t) row & 3) && !(x & 3)

            && !(dst->pitch & 3)) {

            int n = x >> 2;

            for (y = dstrect->h; y; --y) {

                SDL_memset4(row, 0, n);

                row += dst->pitch;

            }

        } else {

#ifdef __powerpc__

            /*

             * SDL_memset() on PPC (both glibc and codewarrior) uses

             * the dcbz (Data Cache Block Zero) instruction, which

             * causes an alignment exception if the destination is

             * uncachable, so only use it on software surfaces

             */

            if (dst->flags & SDL_HWSURFACE) {

                if (dstrect->w >= 8) {

                    /*

                     * 64-bit stores are probably most

                     * efficient to uncached video memory

                     */

                    double fill;

                    SDL_memset(&fill, color, (sizeof fill));

                    for (y = dstrect->h; y; y--) {

                        Uint8 *d = row;

                        unsigned n = x;

                        unsigned nn;

                        Uint8 c = color;

                        double f = fill;

                        while ((unsigned long) d & (sizeof(double) - 1)) {

                            *d++ = c;

                            n--;

                        }

                        nn = n / (sizeof(double) * 4);

                        while (nn) {

                            ((double *) d)[0] = f;

                            ((double *) d)[1] = f;

                            ((double *) d)[2] = f;

                            ((double *) d)[3] = f;

                            d += 4 * sizeof(double);

                            nn--;

                        }

                        n &= ~(sizeof(double) * 4 - 1);

                        nn = n / sizeof(double);

                        while (nn) {

                            *(double *) d = f;

                            d += sizeof(double);

                            nn--;

                        }

                        n &= ~(sizeof(double) - 1);

                        while (n) {

                            *d++ = c;

                            n--;

                        }

                        row += dst->pitch;

                    }

                } else {

                    /* narrow boxes */

                    for (y = dstrect->h; y; y--) {

                        Uint8 *d = row;

                        Uint8 c = color;

                        int n = x;

                        while (n) {

                            *d++ = c;

                            n--;

                        }

                        row += dst->pitch;

                    }

                }

            } else

#endif /* __powerpc__ */

            {

                for (y = dstrect->h; y; y--) {

                    SDL_memset(row, color, x);

                    row += dst->pitch;

                }

            }

        }

    } else {

        switch (dst->format->BytesPerPixel) {

        case 2:

            for (y = dstrect->h; y; --y) {

                Uint16 *pixels = (Uint16 *) row;

                Uint16 c = (Uint16) color;

                Uint32 cc = (Uint32) c << 16 | c;

                int n = dstrect->w;

                if ((uintptr_t) pixels & 3) {

                    *pixels++ = c;

                    n--;

                }

                if (n >> 1)

                    SDL_memset4(pixels, cc, n >> 1);

                if (n & 1)

                    pixels[n - 1] = c;

                row += dst->pitch;

            }

            break;

        case 3:

#if SDL_BYTEORDER == SDL_BIG_ENDIAN

            color <<= 8;

#endif

            for (y = dstrect->h; y; --y) {

                Uint8 *pixels = row;

                for (x = dstrect->w; x; --x) {

                    SDL_memcpy(pixels, &color, 3);

                    pixels += 3;

                }

                row += dst->pitch;

            }

            break;

        case 4:

            for (y = dstrect->h; y; --y) {

                SDL_memset4(row, color, dstrect->w);

                row += dst->pitch;

            }

            break;

        }

    }

    SDL_UnlockSurface(dst);

    /* We're done! */

    return (0);

}

/*

 * Lock a surface to directly access the pixels

 */

int

SDL_LockSurface(SDL_Surface * surface)

{

    if (!surface->locked) {

        /* Perform the lock */

        if (surface->flags & SDL_HWSURFACE) {

            if (SDL_LockTexture

                (surface->textureID, NULL, 1, &surface->pixels,

                 &surface->pitch) < 0) {

                return (-1);

            }

        }

        if (surface->flags & SDL_RLEACCEL) {

            SDL_UnRLESurface(surface, 1);

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

        }

    }

    /* Increment the surface lock count, for recursive locks */

    ++surface->locked;

    /* Ready to go.. */

    return (0);

}

/*

 * Unlock a previously locked surface

 */

void

SDL_UnlockSurface(SDL_Surface * surface)

{

    /* Only perform an unlock if we are locked */

    if (!surface->locked || (--surface->locked > 0)) {

        return;

    }

    /* Unlock hardware or accelerated surfaces */

    if (surface->flags & SDL_HWSURFACE) {

        SDL_UnlockTexture(surface->textureID);

    }

    /* Update RLE encoded surface with new data */

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

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

        SDL_RLESurface(surface);

    }

}

/* 

 * Convert a surface into the specified pixel format.

 */

SDL_Surface *

SDL_ConvertSurface(SDL_Surface * surface,

                   SDL_PixelFormat * format, Uint32 flags)

{

    SDL_Surface *convert;

    Uint32 colorkey = 0;

    Uint8 alpha = 0;

    Uint32 surface_flags;

    SDL_Rect bounds;

    /* Check for empty destination palette! (results in empty image) */

    if (format->palette != NULL) {

        int i;

        for (i = 0; i < format->palette->ncolors; ++i) {

            if ((format->palette->colors[i].r != 0xFF) ||

                (format->palette->colors[i].g != 0xFF) ||

                (format->palette->colors[i].b != 0xFF))

                break;

        }

        if (i == format->palette->ncolors) {

            SDL_SetError("Empty destination palette");

            return (NULL);

        }

    }

    /* Create a new surface with the desired format */

    convert = SDL_CreateRGBSurface(flags,

                                   surface->w, surface->h,

                                   format->BitsPerPixel, format->Rmask,

                                   format->Gmask, format->Bmask,

                                   format->Amask);

    if (convert == NULL) {

        return (NULL);

    }

    /* Copy the palette if any */

    if (format->palette && convert->format->palette) {

        SDL_memcpy(convert->format->palette->colors,

                   format->palette->colors,

                   format->palette->ncolors * sizeof(SDL_Color));

        convert->format->palette->ncolors = format->palette->ncolors;

    }

    /* Save the original surface color key and alpha */

    surface_flags = surface->flags;

    if ((surface_flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {

        /* Convert colourkeyed surfaces to RGBA if requested */

        if ((flags & SDL_SRCCOLORKEY) != SDL_SRCCOLORKEY && format->Amask) {

            surface_flags &= ~SDL_SRCCOLORKEY;

        } else {

            colorkey = surface->format->colorkey;

            SDL_SetColorKey(surface, 0, 0);

        }

    }

    if ((surface_flags & SDL_SRCALPHA) == SDL_SRCALPHA) {

        /* Copy over the alpha channel to RGBA if requested */

        if (format->Amask) {

            surface->flags &= ~SDL_SRCALPHA;

        } else {

            alpha = surface->format->alpha;

            SDL_SetAlpha(surface, 0, 0);

        }

    }

    /* Copy over the image data */

    bounds.x = 0;

    bounds.y = 0;

    bounds.w = surface->w;

    bounds.h = surface->h;

    SDL_LowerBlit(surface, &bounds, convert, &bounds);

    /* Clean up the original surface, and update converted surface */

    if (convert != NULL) {

        SDL_SetClipRect(convert, &surface->clip_rect);

    }

    if ((surface_flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {

        Uint32 cflags = surface_flags & (SDL_SRCCOLORKEY | SDL_RLEACCELOK);

        if (convert != NULL) {

            Uint8 keyR, keyG, keyB;

            SDL_GetRGB(colorkey, surface->format, &keyR, &keyG, &keyB);

            SDL_SetColorKey(convert, cflags | (flags & SDL_RLEACCELOK),

                            SDL_MapRGB(convert->format, keyR, keyG, keyB));

        }

        SDL_SetColorKey(surface, cflags, colorkey);

    }

    if ((surface_flags & SDL_SRCALPHA) == SDL_SRCALPHA) {

        Uint32 aflags = surface_flags & (SDL_SRCALPHA | SDL_RLEACCELOK);

        if (convert != NULL) {

            SDL_SetAlpha(convert, aflags | (flags & SDL_RLEACCELOK), alpha);

        }

        if (format->Amask) {

            surface->flags |= SDL_SRCALPHA;

        } else {

            SDL_SetAlpha(surface, aflags, alpha);

        }

    }

    /* We're ready to go! */

    return (convert);

}

/*

 * Free a surface created by the above function.

 */

void

SDL_FreeSurface(SDL_Surface * surface)

{

    if (surface == NULL) {

        return;

    }

    if (--surface->refcount > 0) {

        return;

    }

    while (surface->locked > 0) {

        SDL_UnlockSurface(surface);

    }

    if (surface->flags & SDL_RLEACCEL) {

        SDL_UnRLESurface(surface, 0);

    }

    if (surface->format) {

        SDL_SetSurfacePalette(surface, NULL);

        SDL_FreeFormat(surface->format);

        surface->format = NULL;

    }

    if (surface->map != NULL) {

        SDL_FreeBlitMap(surface->map);

        surface->map = NULL;

    }

    /* Should we destroy the texture too?

       if (surface->textureID) {

       SDL_DestroyTexture(surface->textureID);

       }

     */

    if (surface->pixels && ((surface->flags & SDL_PREALLOC) != SDL_PREALLOC)) {

        SDL_free(surface->pixels);

    }

    SDL_free(surface);

#ifdef CHECK_LEAKS

    --surfaces_allocated;

#endif

}

/* vi: set ts=4 sw=4 expandtab: */