Béziers

[ipdf/code.git] / src / bezier.cpp

diff --git a/src/bezier.cpp b/src/bezier.cpp
new file mode 100644 (file)
index 0000000..15a5069
--- /dev/null
+++ b/src/bezier.cpp
@@ -0,0 +1,48 @@
+#include "bezier.h"
+
+#include <unordered_map>
+#include <cmath>
+
+using namespace std;
+
+namespace IPDF
+{
+
+/**
+ * Factorial
+ * Use dynamic programming / recursion
+ */
+int Factorial(int n)
+{
+       static unordered_map<int, int> dp;
+       static bool init = false;
+       if (!init)
+       {
+               init = true;
+               dp[0] = 1;
+       }
+       auto it = dp.find(n);
+       if (it != dp.end())
+               return it->second;
+       int result = n*Factorial(n-1);
+       dp[n] = result;
+       return result;
+}
+
+/**
+ * Binomial coefficients
+ */
+int BinomialCoeff(int n, int k)
+{
+       return Factorial(n) / Factorial(k) / Factorial(n-k);
+}
+
+/**
+ * Bernstein Basis Polynomial
+ */
+Real Bernstein(int k, int n, const Real & u)
+{
+       return Real(BinomialCoeff(n, k)) * pow(u, k) * pow(Real(1.0) - u, n-k);
+}
+
+}