view src/video/SDL_surface.c @ 3502:98a819296cdc

Whenever a window becomes fullscreen, shown, unminimized, and has input focus it will change the display to the corresponding fullscreen video mode. If it loses any of those properties the desktop mode will be restored.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 01 Dec 2009 08:56:12 +0000
parents 0538362b98d3
children 5543db4239e6
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 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;

    /* The flags are no longer used, make the compiler happy */
    flags;

    /* 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;
    }
    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);

    /* By default surface with an alpha mask are set up for blending */
    if (Amask) {
        SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);
    }

    /* 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;
}

static int
SDL_SurfacePaletteChanged(void *userdata, SDL_Palette * palette)
{
    SDL_Surface *surface = (SDL_Surface *) userdata;

    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;
}

int
SDL_SetSurfaceRLE(SDL_Surface * surface, int flag)
{
    int flags;

    if (!surface) {
        return -1;
    }

    flags = surface->map->info.flags;
    if (flag) {
        surface->map->info.flags |= SDL_COPY_RLE_DESIRED;
    } else {
        surface->map->info.flags &= ~SDL_COPY_RLE_DESIRED;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return 0;
}

int
SDL_SetColorKey(SDL_Surface * surface, Uint32 flag, Uint32 key)
{
    int flags;

    if (!surface) {
        return -1;
    }

    if (flag & SDL_RLEACCEL) {
        SDL_SetSurfaceRLE(surface, 1);
    }

    flags = surface->map->info.flags;
    if (flag) {
        surface->map->info.flags |= SDL_COPY_COLORKEY;
        surface->map->info.colorkey = key;
    } else {
        surface->map->info.flags &= ~SDL_COPY_COLORKEY;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }

    /* Compatibility mode */
    if (surface->map->info.flags & SDL_COPY_COLORKEY) {
        surface->flags |= SDL_SRCCOLORKEY;
    } else {
        surface->flags &= ~SDL_SRCCOLORKEY;
    }

    return 0;
}

int
SDL_GetColorKey(SDL_Surface * surface, Uint32 * key)
{
    if (!surface) {
        return -1;
    }

    if (!(surface->map->info.flags & SDL_COPY_COLORKEY)) {
        return -1;
    }

    if (key) {
        *key = surface->map->info.colorkey;
    }
    return 0;
}

/* This is a fairly slow function to switch from colorkey to alpha */
static void
SDL_ConvertColorkeyToAlpha(SDL_Surface * surface)
{
    int x, y;

    if (!surface) {
        return;
    }

    if (!(surface->map->info.flags & SDL_COPY_COLORKEY) ||
        !surface->format->Amask) {
        return;
    }

    SDL_LockSurface(surface);

    switch (surface->format->BytesPerPixel) {
    case 2:
        {
            Uint16 *row, *spot;
            Uint16 ckey = (Uint16) surface->map->info.colorkey;
            Uint16 mask = (Uint16) (~surface->format->Amask);

            row = (Uint16 *) surface->pixels;
            for (y = surface->h; y--;) {
                spot = row;
                for (x = surface->w; x--;) {
                    if (*spot == ckey) {
                        *spot &= mask;
                    }
                    ++spot;
                }
                row += surface->pitch / 2;
            }
        }
        break;
    case 3:
        /* FIXME */
        break;
    case 4:
        {
            Uint32 *row, *spot;
            Uint32 ckey = surface->map->info.colorkey;
            Uint32 mask = ~surface->format->Amask;

            row = (Uint32 *) surface->pixels;
            for (y = surface->h; y--;) {
                spot = row;
                for (x = surface->w; x--;) {
                    if (*spot == ckey) {
                        *spot &= mask;
                    }
                    ++spot;
                }
                row += surface->pitch / 4;
            }
        }
        break;
    }

    SDL_UnlockSurface(surface);

    SDL_SetColorKey(surface, 0, 0);
    SDL_SetSurfaceBlendMode(surface, SDL_BLENDMODE_BLEND);
}

int
SDL_SetSurfaceColorMod(SDL_Surface * surface, Uint8 r, Uint8 g, Uint8 b)
{
    int flags;

    if (!surface) {
        return -1;
    }

    surface->map->info.r = r;
    surface->map->info.g = g;
    surface->map->info.b = b;

    flags = surface->map->info.flags;
    if (r != 0xFF || g != 0xFF || b != 0xFF) {
        surface->map->info.flags |= SDL_COPY_MODULATE_COLOR;
    } else {
        surface->map->info.flags &= ~SDL_COPY_MODULATE_COLOR;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return 0;
}


int
SDL_GetSurfaceColorMod(SDL_Surface * surface, Uint8 * r, Uint8 * g, Uint8 * b)
{
    if (!surface) {
        return -1;
    }

    if (r) {
        *r = surface->map->info.r;
    }
    if (g) {
        *g = surface->map->info.g;
    }
    if (b) {
        *b = surface->map->info.b;
    }
    return 0;
}

int
SDL_SetSurfaceAlphaMod(SDL_Surface * surface, Uint8 alpha)
{
    int flags;

    if (!surface) {
        return -1;
    }

    surface->map->info.a = alpha;

    flags = surface->map->info.flags;
    if (alpha != 0xFF) {
        surface->map->info.flags |= SDL_COPY_MODULATE_ALPHA;
    } else {
        surface->map->info.flags &= ~SDL_COPY_MODULATE_ALPHA;
    }
    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return 0;
}

int
SDL_GetSurfaceAlphaMod(SDL_Surface * surface, Uint8 * alpha)
{
    if (!surface) {
        return -1;
    }

    if (alpha) {
        *alpha = surface->map->info.a;
    }
    return 0;
}

int
SDL_SetSurfaceBlendMode(SDL_Surface * surface, int blendMode)
{
    int flags, status;

    if (!surface) {
        return -1;
    }

    status = 0;
    flags = surface->map->info.flags;
    surface->map->info.flags &=
        ~(SDL_COPY_MASK | SDL_COPY_BLEND | SDL_COPY_ADD | SDL_COPY_MOD);
    switch (blendMode) {
    case SDL_BLENDMODE_NONE:
        break;
    case SDL_BLENDMODE_MASK:
        surface->map->info.flags |= SDL_COPY_MASK;
        break;
    case SDL_BLENDMODE_BLEND:
        surface->map->info.flags |= SDL_COPY_BLEND;
        break;
    case SDL_BLENDMODE_ADD:
        surface->map->info.flags |= SDL_COPY_ADD;
        break;
    case SDL_BLENDMODE_MOD:
        surface->map->info.flags |= SDL_COPY_MOD;
        break;
    default:
        SDL_Unsupported();
        status = -1;
        break;
    }

    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }

    /* Compatibility mode */
    if (surface->map->info.flags & SDL_COPY_BLEND) {
        surface->flags |= SDL_SRCALPHA;
    } else {
        surface->flags &= ~SDL_SRCALPHA;
    }

    return status;
}

int
SDL_GetSurfaceBlendMode(SDL_Surface * surface, int *blendMode)
{
    if (!surface) {
        return -1;
    }

    if (!blendMode) {
        return 0;
    }

    switch (surface->map->
            info.flags & (SDL_COPY_MASK | SDL_COPY_BLEND | SDL_COPY_ADD |
                          SDL_COPY_MOD)) {
    case SDL_COPY_MASK:
        *blendMode = SDL_BLENDMODE_MASK;
        break;
    case SDL_COPY_BLEND:
        *blendMode = SDL_BLENDMODE_BLEND;
        break;
    case SDL_COPY_ADD:
        *blendMode = SDL_BLENDMODE_ADD;
        break;
    case SDL_COPY_MOD:
        *blendMode = SDL_BLENDMODE_MOD;
        break;
    default:
        *blendMode = SDL_BLENDMODE_NONE;
        break;
    }
    return 0;
}

int
SDL_SetSurfaceScaleMode(SDL_Surface * surface, int scaleMode)
{
    int flags, status;

    if (!surface) {
        return -1;
    }

    status = 0;
    flags = surface->map->info.flags;
    surface->map->info.flags &= ~(SDL_COPY_NEAREST);
    switch (scaleMode) {
    case SDL_TEXTURESCALEMODE_NONE:
        break;
    case SDL_TEXTURESCALEMODE_FAST:
        surface->map->info.flags |= SDL_COPY_NEAREST;
        break;
    case SDL_TEXTURESCALEMODE_SLOW:
    case SDL_TEXTURESCALEMODE_BEST:
        SDL_Unsupported();
        surface->map->info.flags |= SDL_COPY_NEAREST;
        status = -1;
        break;
    default:
        SDL_Unsupported();
        status = -1;
        break;
    }

    if (surface->map->info.flags != flags) {
        SDL_InvalidateMap(surface->map);
    }
    return status;
}

int
SDL_GetSurfaceScaleMode(SDL_Surface * surface, int *scaleMode)
{
    if (!surface) {
        return -1;
    }

    if (!scaleMode) {
        return 0;
    }

    switch (surface->map->info.flags & SDL_COPY_NEAREST) {
    case SDL_COPY_NEAREST:
        *scaleMode = SDL_TEXTURESCALEMODE_FAST;
        break;
    default:
        *scaleMode = SDL_TEXTURESCALEMODE_NONE;
        break;
    }
    return 0;
}

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);
        }
        /* just here for debugging */
/*         printf */
/*             ("src = 0x%08X src->flags = %08X src->map->info.flags = %08x\ndst = 0x%08X dst->flags = %08X dst->map->info.flags = %08X\nsrc->map->blit = 0x%08x\n", */
/*              src, dst->flags, src->map->info.flags, dst, dst->flags, */
/*              dst->map->info.flags, src->map->blit); */
    }
    return (src->map->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;
}

/*
 * Lock a surface to directly access the pixels
 */
int
SDL_LockSurface(SDL_Surface * surface)
{
    if (!surface->locked) {
        /* Perform the lock */
        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;
    }

    /* 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 copy_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 copy flags */
    copy_flags = surface->map->info.flags;
    surface->map->info.flags = 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 */
    convert->map->info.r = surface->map->info.r;
    convert->map->info.g = surface->map->info.g;
    convert->map->info.b = surface->map->info.b;
    convert->map->info.a = surface->map->info.a;
    convert->map->info.flags =
        (copy_flags &
         ~(SDL_COPY_COLORKEY | SDL_COPY_BLEND
           | SDL_COPY_RLE_DESIRED | SDL_COPY_RLE_COLORKEY |
           SDL_COPY_RLE_ALPHAKEY));
    surface->map->info.flags = copy_flags;
    if (copy_flags & SDL_COPY_COLORKEY) {
        Uint8 keyR, keyG, keyB, keyA;

        SDL_GetRGBA(surface->map->info.colorkey, surface->format, &keyR,
                    &keyG, &keyB, &keyA);
        SDL_SetColorKey(convert, 1,
                        SDL_MapRGBA(convert->format, keyR, keyG, keyB, keyA));
        /* This is needed when converting for 3D texture upload */
        SDL_ConvertColorkeyToAlpha(convert);
    }
    SDL_SetClipRect(convert, &surface->clip_rect);

    /* Enable alpha blending by default if the new surface has an
     * alpha channel or alpha modulation */
    if ((surface->format->Amask && format->Amask) ||
        (copy_flags & SDL_COPY_MODULATE_ALPHA)) {
        SDL_SetSurfaceBlendMode(convert, SDL_BLENDMODE_BLEND);
    }
    if ((copy_flags & SDL_COPY_RLE_DESIRED) || (flags & SDL_RLEACCEL)) {
        SDL_SetSurfaceRLE(convert, SDL_RLEACCEL);
    }

    /* We're ready to go! */
    return (convert);
}

/*
 * Create a surface on the stack for quick blit operations
 */
static __inline__ SDL_bool
SDL_CreateSurfaceOnStack(int width, int height, Uint32 pixel_format,
                         void * pixels, int pitch, SDL_Surface * surface, 
                         SDL_PixelFormat * format, SDL_BlitMap * blitmap)
{
    int bpp;
    Uint32 Rmask, Gmask, Bmask, Amask;

    if (!SDL_PixelFormatEnumToMasks(pixel_format,
                                    &bpp, &Rmask, &Gmask, &Bmask, &Amask)) {
        return SDL_FALSE;
    }
    if (bpp <= 8) {
        SDL_SetError("Indexed pixel formats not supported");
        return SDL_FALSE;
    }

    SDL_zerop(surface);
    surface->flags = SDL_PREALLOC;
    surface->format = SDL_InitFormat(format, bpp, Rmask, Gmask, Bmask, Amask);
    surface->pixels = pixels;
    surface->w = width;
    surface->h = height;
    surface->pitch = pitch;
    /* We don't actually need to set up the clip rect for our purposes */
    /*SDL_SetClipRect(surface, NULL);*/

    /* Allocate an empty mapping */
    SDL_zerop(blitmap);
    blitmap->info.r = 0xFF;
    blitmap->info.g = 0xFF;
    blitmap->info.b = 0xFF;
    blitmap->info.a = 0xFF;
    surface->map = blitmap;
    SDL_FormatChanged(surface);

    /* The surface is ready to go */
    surface->refcount = 1;
    return SDL_TRUE;
}

/*
 * Copy a block of pixels of one format to another format
 */
int SDL_ConvertPixels(int width, int height,
                      Uint32 src_format, const void * src, int src_pitch,
                      Uint32 dst_format, void * dst, int dst_pitch)
{
    SDL_Surface src_surface, dst_surface;
    SDL_PixelFormat src_fmt, dst_fmt;
    SDL_BlitMap src_blitmap, dst_blitmap;
    SDL_Rect rect;

    /* Fast path for same format copy */
    if (src_format == dst_format) {
        int bpp;

        if (SDL_ISPIXELFORMAT_FOURCC(src_format)) {
            switch (src_format) {
            case SDL_PIXELFORMAT_YV12:
            case SDL_PIXELFORMAT_IYUV:
            case SDL_PIXELFORMAT_YUY2:
            case SDL_PIXELFORMAT_UYVY:
            case SDL_PIXELFORMAT_YVYU:
                bpp = 2;
            default:
                SDL_SetError("Unknown FOURCC pixel format");
                return -1;
            }
        } else {
            bpp = SDL_BYTESPERPIXEL(src_format);
        }
        width *= bpp;

        while (height-- > 0) {
            SDL_memcpy(dst, src, width);
            src = (Uint8*)src + src_pitch;
            dst = (Uint8*)dst + dst_pitch;
        }
        return SDL_TRUE;
    }

    if (!SDL_CreateSurfaceOnStack(width, height, src_format, (void*)src,
                                  src_pitch,
                                  &src_surface, &src_fmt, &src_blitmap)) {
        return -1;
    }
    if (!SDL_CreateSurfaceOnStack(width, height, dst_format, dst, dst_pitch,
                                  &dst_surface, &dst_fmt, &dst_blitmap)) {
        return -1;
    }

    /* Set up the rect and go! */
    rect.x = 0;
    rect.y = 0;
    rect.w = width;
    rect.h = height;
    return SDL_LowerBlit(&src_surface, &rect, &dst_surface, &rect);
}

/*
 * 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;
    }
    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: */