Add riemman surfaces family

src/surface.c

@@ -1,3 +1,4 @@
+#include <complex.h>
 #include <math.h>
 #include <stdlib.h>
 
@@ -9,6 +10,25 @@
 #define M_PI 3.14159265358979323846
 #endif
 
+#ifndef CMPLX
+#define CMPLX(a,b) (a+I*b)
+#endif
+
+void riemman(float *d_surface, int * coords, int grid_size)
+{
+	complex double eq;
+	float u = 2 * ((float)coords[0] / grid_size) - 1;
+	float v = 2 * ((float)coords[1] / grid_size) - 1;
+
+	eq = csqrt(CMPLX(u,v));
+
+	d_surface[0] = u;
+	d_surface[1] = v;
+	d_surface[2] = creal(eq);
+	d_surface[3] = cimag(eq);
+}
+
+
 void mobius(float *d_surface, int * coord, int grid_size)
 {
 	const float width = 0.5;