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view dmscaledblit.h @ 510:43ea59887c69

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Start work on making C64 formats encoding possible by changing DMDecodeOps to DMEncDecOps and adding fields and op enums for custom encode functions, renaming, etc. Split generic op sanity checking into a separate function in preparation for its use in generic encoding function.
author Matti Hamalainen <ccr@tnsp.org>
date Mon, 19 Nov 2012 15:06:01 +0200
parents 79dac918c81e
children eba3b87f3f84
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/*
 * DMLib
 * -- Scaled sprite / surface blitting function template
 * Programmed and designed by Matti 'ccr' Hamalainen
 * (C) Copyright 2011-2012 Tecnic Software productions (TNSP)
 */


int DM_BLITFUNC_NAME (SDL_Surface *src,
    const int x0, const int y0,
    const int dwidth, const int dheight,
    SDL_Surface *dst
#ifdef DM_BLITFUNC_ARGS
    DM_BLITFUNC_ARGS
#endif
    )
#ifdef DM_HEADER
;
#else
{
    int yc;
    DMFixedPoint32 xv, yv, dx, dy;
    DMQValue xr, yr;

#ifdef DM_BLITFUNC_VARS
    DM_BLITFUNC_VARS
#endif
    
    // Clip coordinates
    if (dmScaledClipCoord(&xr, x0, src->w, dwidth, 
        dst->clip_rect.x, dst->clip_rect.x + dst->clip_rect.w)
        ||
        dmScaledClipCoord(&yr, y0, src->h, dheight,
        dst->clip_rect.y, dst->clip_rect.y + dst->clip_rect.h))
        return -1;

#ifdef DM_BLITFUNC_INIT
    DM_BLITFUNC_INIT
#endif

    // Calculate "final" initial source bitmap offsets
    FP_CONV(dy, yr.voffs);
    FP_MUL_R(yv, dy, yr.vdelta);

    FP_CONV(dx, xr.voffs);
    FP_MUL_R(dx, dx, xr.vdelta);

    // Take pitch into account
    const int dstadd = xr.vadd - dst->clip_rect.w + dst->clip_rect.x + (dst->pitch / DM_BLITFUNC_DST_BYTES);

    // Blit scaled
    DM_BLITFUNC_DST_TYPE * dp = ((DM_BLITFUNC_DST_TYPE *) dst->pixels) + (yr.v0 * dst->pitch) / DM_BLITFUNC_DST_BYTES + xr.v0;
    for (yc = yr.v0; yc < yr.v1; yc++)
    {
        const DM_BLITFUNC_SRC_TYPE * sp = ((DM_BLITFUNC_SRC_TYPE *) src->pixels) + (FP_GETH(yv) * src->pitch) / DM_BLITFUNC_SRC_BYTES;
        int xc;

#ifdef DM_BLITFUNC_INNER_INIT
        DM_BLITFUNC_INNER_INIT
#endif

        for (xv.dw = dx.dw, xc = xr.v0; xc < xr.v1; xc++)
        {
            DM_BLITFUNC_INNER
            FP_ADD(xv, xr.vdelta);
        }
        FP_ADD(yv, yr.vdelta);
        dp += dstadd;
    }

#ifdef DM_BLITFUNC_FINISH
    DM_BLITFUNC_FINISH
#endif

    return 0;
}
#endif

#undef DM_BLITFUNC_NAME
#undef DM_BLITFUNC_ARGS
#undef DM_BLITFUNC_SRC_BYTES
#undef DM_BLITFUNC_DST_BYTES
#undef DM_BLITFUNC_SRC_TYPE
#undef DM_BLITFUNC_DST_TYPE
#undef DM_BLITFUNC_VARS
#undef DM_BLITFUNC_INIT
#undef DM_BLITFUNC_INNER_INIT
#undef DM_BLITFUNC_INNER
#undef DM_BLITFUNC_FINISH