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view dmscaledblit.h @ 96:6bf5220fa47e

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Urgh .. use memset to silence some bogus GCC warnings about using potentially uninitialized values, while that will not actually be possible. In any case, it is annoying.
author Matti Hamalainen <ccr@tnsp.org>
date Tue, 02 Oct 2012 18:52:28 +0300
parents 0430f484641b
children 79dac918c81e
line wrap: on
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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
    )
{
    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;
}


#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