static void xy_interp(int line, int samp,
int line_lo, int line_hi, int samp_lo, int samp_hi,
double *lines, double *samps,
double *interp_line, double *interp_samp)
{
assert(samp>=samp_lo && samp<=samp_hi);
assert(line>=line_lo && line<=line_hi);
double l = (double)(line - line_lo) / (double)(line_hi - line_lo);
double s = (double)(samp - samp_lo) / (double)(samp_hi - samp_lo);
*interp_line = bilinear_interp_fn(l, s, lines[0], lines[1], lines[2], lines[3]);
*interp_samp = bilinear_interp_fn(l, s, samps[0], samps[1], samps[2], samps[3]);
}
static void xy_interp(int line, int samp,
int line_lo, int line_hi, int samp_lo, int samp_hi,
double *lats, double *lons,
double *interp_lat, double *interp_lon)
{
assert(samp>=samp_lo && samp<=samp_hi);
assert(line>=line_lo && line<=line_hi);
double l = (double)(line - line_lo) / (double)(line_hi - line_lo);
double s = (double)(samp - samp_lo) / (double)(samp_hi - samp_lo);
*interp_lat = bilinear_interp_fn(l, s, lats[0], lats[1], lats[2], lats[3]);
*interp_lon = bilinear_interp_fn(l, s, lons[0], lons[1], lons[2], lons[3]);
}
static void test_interp()
{
check(1, bilinear_interp_fn(.5,.5,1,1,1,1), 1);
check(2, bilinear_interp_fn(.1,.1,1,1,1,1), 1);
check(3, bilinear_interp_fn(.5,.5,1,1,2,2), 1.5);
check(4, bilinear_interp_fn(.5,.5,1,2,1,2), 1.5);
check(5, bilinear_interp_fn(.5,.5,1,2,1,2), 1.5);
check(6, bilinear_interp_fn(0,0,1,2,3,4), 1);
check(7, bilinear_interp_fn(1,1,1,2,3,4), 4);
check(8, bilinear_interp_fn(0,1,1,2,3,4), 2);
check(9, bilinear_interp_fn(1,0,1,2,3,4), 3);
}
static float
interp_demData(float *demData, int nl, int ns, double l, double s)
{
if (l<0 || l>=nl-1 || s<0 || s>=ns-1) {
return 0;
}
int ix = (int)s;
int iy = (int)l;
int bilinear = l<3 || l>=nl-3 || s<3 || s>=ns-3;
//int bilinear = 1;
if (bilinear) {
float p00 = demData[ix + ns*(iy )];
float p10 = demData[ix+1 + ns*(iy )];
float p01 = demData[ix + ns*(iy+1)];
float p11 = demData[ix+1 + ns*(iy+1)];
return (float)bilinear_interp_fn(s-ix, l-iy, p00, p10, p01, p11);
}
else {
double ret, x[4], y[4], xi[4], yi[4];
int ii;
for (ii=0; ii<4; ++ii) {
y[0] = demData[ix-1 + ns*(iy+ii-1)];
y[1] = demData[ix + ns*(iy+ii-1)];
y[2] = demData[ix+1 + ns*(iy+ii-1)];
y[3] = demData[ix+2 + ns*(iy+ii-1)];
x[0] = ix - 1;
x[1] = ix;
x[2] = ix + 1;
x[3] = ix + 2;
gsl_interp_accel *acc = gsl_interp_accel_alloc ();
gsl_spline *spline = gsl_spline_alloc (gsl_interp_cspline, 4);
gsl_spline_init (spline, x, y, 4);
yi[ii] = gsl_spline_eval_check(spline, s, acc);
gsl_spline_free (spline);
gsl_interp_accel_free (acc);
xi[ii] = iy + ii - 1;
}
gsl_interp_accel *acc = gsl_interp_accel_alloc ();
gsl_spline *spline = gsl_spline_alloc (gsl_interp_cspline, 4);
gsl_spline_init (spline, xi, yi, 4);
ret = gsl_spline_eval_check(spline, l, acc);
gsl_spline_free (spline);
gsl_interp_accel_free (acc);
return (float)ret;
}
asfPrintError("Impossible.");
}
static float
interp_dem(FloatImage *dem, double l, double s)
{
int nl = dem->size_y;
int ns = dem->size_x;
if (l<0 || l>=nl-1 || s<0 || s>=ns-1) {
return 0;
}
int ix = (int)s;
int iy = (int)l;
int bilinear = l<3 || l>=nl-3 || s<3 || s>=ns-3;
//int bilinear = 1;
if (bilinear) {
float p00 = float_image_get_pixel(dem, ix, iy);
float p10 = float_image_get_pixel(dem, ix+1, iy);
float p01 = float_image_get_pixel(dem, ix, iy+1);
float p11 = float_image_get_pixel(dem, ix+1, iy+1);
return (float)bilinear_interp_fn(s-ix, l-iy, p00, p10, p01, p11);
}
else {
double ret, x[4], y[4], xi[4], yi[4];
int ii;
for (ii=0; ii<4; ++ii) {
y[0] = float_image_get_pixel(dem, ix-1, iy+ii-1);
y[1] = float_image_get_pixel(dem, ix, iy+ii-1);
y[2] = float_image_get_pixel(dem, ix+1, iy+ii-1);
y[3] = float_image_get_pixel(dem, ix+2, iy+ii-1);
x[0] = ix - 1;
x[1] = ix;
x[2] = ix + 1;
x[3] = ix + 2;
gsl_interp_accel *acc = gsl_interp_accel_alloc ();
gsl_spline *spline = gsl_spline_alloc (gsl_interp_cspline, 4);
gsl_spline_init (spline, x, y, 4);
yi[ii] = gsl_spline_eval_check(spline, s, acc);
gsl_spline_free (spline);
gsl_interp_accel_free (acc);
xi[ii] = iy + ii - 1;
}
gsl_interp_accel *acc = gsl_interp_accel_alloc ();
gsl_spline *spline = gsl_spline_alloc (gsl_interp_cspline, 4);
gsl_spline_init (spline, xi, yi, 4);
ret = gsl_spline_eval_check(spline, l, acc);
gsl_spline_free (spline);
gsl_interp_accel_free (acc);
return (float)ret;
}
asfPrintError("Impossible.");
}
