gsdiff.c

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#include <grass/gstypes.h>
#include "gsget.h"

static geosurf *Refsurf = NULL;
static typbuff *Refbuff = NULL;
static float Refscale = 1.0;

void gsdiff_set_SDscale(float scale)
{
    Refscale = scale;

    return;
}

float gsdiff_get_SDscale(void)
{
    return (Refscale);
}

void gsdiff_set_SDref(geosurf * gsref)
{
    Refsurf = gsref;
    Refbuff = gs_get_att_typbuff(gsref, ATT_TOPO, 0);

    return;
}

geosurf *gsdiff_get_SDref(void)
{
    if (Refsurf && Refbuff) {
        return (Refsurf);
    }

    return (NULL);
}

float gsdiff_do_SD(float val, int offset)
{
    float ref;

    if (Refbuff) {
        GET_MAPATT(Refbuff, offset, ref);
        return (ref + (val - ref) * Refscale);
    }

    return (val);
}