rename engine to src

src/bezier.h

@@ -0,0 +1,66 @@
+#pragma once
+
+
+class BezierCurve
+{
+    static double FactorialLookup[33];
+public:
+    // just check if n is appropriate, then return the result
+    static double factorial(int n)
+    {
+//         if (n < 0) { throw new Exception("n is less than 0"); }
+//         if (n > 32) { throw new Exception("n is greater than 32"); }
+        return FactorialLookup[n]; /* returns the value n! as a SUMORealing point number */
+    }
+
+    static double Ni(int n, int i)
+    {
+        double ni;
+        double a1 = factorial(n);
+        double a2 = factorial(i);
+        double a3 = factorial(n - i);
+        ni = a1 / (a2 * a3);
+        return ni;
+    }
+
+    // Calculate Bernstein basis
+    static double Bernstein(int n, int i, double t)
+    {
+        double basis;
+        double ti; /* t^i */
+        double tni; /* (1 - t)^i */
+
+        /* Prevent problems with pow */
+
+        if (t == 0.0 && i == 0)
+            ti = 1.0;
+        else
+            ti = pow(t, i);
+
+        if (n == i && t == 1.0)
+            tni = 1.0;
+        else
+            tni = pow((1 - t), (n - i));
+
+        //Bernstein basis
+        basis = Ni(n, i) * ti * tni;
+        return basis;
+    }
+
+    static glm::vec2 Bezier2D(const std::vector<glm::vec2>& b, double t)
+    {
+//         if ((1.0 - t) < 5e-6)
+//             t = 1.0;
+
+        double px = 0.0;
+        double py = 0.0;
+        const int npts = (int)b.size();
+        for (int i = 0; i < npts; i++)
+        {
+            double basis = Bernstein(npts - 1, i, t);
+            px += basis * b[i].x;
+            py += basis * b[i].y;
+        }
+        return { px, py };
+    }
+};