1 files changed, 58 insertions, 0 deletions
diff --git a/src/3rdparty/proj/bchgen.c b/src/3rdparty/proj/bchgen.c
new file mode 100644
index 00000000..fe2ffe6c
--- /dev/null
+++ b/src/3rdparty/proj/bchgen.c
@@ -0,0 +1,58 @@
+/* generate double bivariate Chebychev polynomial */
+#include <projects.h>
+	int
+bchgen(projUV a, projUV b, int nu, int nv, projUV **f, projUV(*func)(projUV)) {
+	int i, j, k;
+	projUV arg, *t, bma, bpa, *c;
+	double d, fac;
+
+	bma.u = 0.5 * (b.u - a.u); bma.v = 0.5 * (b.v - a.v);
+	bpa.u = 0.5 * (b.u + a.u); bpa.v = 0.5 * (b.v + a.v);
+	for ( i = 0; i < nu; ++i) {
+		arg.u = cos(PI * (i + 0.5) / nu) * bma.u + bpa.u;
+		for ( j = 0; j < nv; ++j) {
+			arg.v = cos(PI * (j + 0.5) / nv) * bma.v + bpa.v;
+			f[i][j] = (*func)(arg);
+			if ((f[i][j]).u == HUGE_VAL)
+				return(1);
+		}
+	}
+	if (!(c = (projUV *) vector1(nu, sizeof(projUV)))) return 1;
+	fac = 2. / nu;
+	for ( j = 0; j < nv ; ++j) {
+		for ( i = 0; i < nu; ++i) {
+			arg.u = arg.v = 0.;
+			for (k = 0; k < nu; ++k) {
+				d = cos(PI * i * (k + .5) / nu);
+				arg.u += f[k][j].u * d;
+				arg.v += f[k][j].v * d;
+			}
+			arg.u *= fac;
+			arg.v *= fac;
+			c[i] = arg;
+		}
+		for (i = 0; i < nu; ++i)
+			f[i][j] = c[i];
+	}
+	pj_dalloc(c);
+	if (!(c = (projUV*) vector1(nv, sizeof(projUV)))) return 1;
+	fac = 2. / nv;
+	for ( i = 0; i < nu; ++i) {
+		t = f[i];
+		for (j = 0; j < nv; ++j) {
+			arg.u = arg.v = 0.;
+			for (k = 0; k < nv; ++k) {
+				d = cos(PI * j * (k + .5) / nv);
+				arg.u += t[k].u * d;
+				arg.v += t[k].v * d;
+			}
+			arg.u *= fac;
+			arg.v *= fac;
+			c[j] = arg;
+		}
+		f[i] = c;
+		c = t;
+	}
+	pj_dalloc(c);
+	return(0);
+}