added von mises distributionb

quick&dirty: added activity to the grid-walkers

math/distribution/LUT.h

@@ -0,0 +1,58 @@
+#ifndef LUT_H
+#define LUT_H
+
+#include <vector>
+#include "../Math.h"
+
+namespace Distribution {
+
+	template <typename Scalar> class LUT {
+
+	private:
+
+		Scalar min;
+		Scalar max;
+		Scalar diff;
+
+		/** number of samples between min and max */
+		int numSamples;
+
+		/** the look-up-table */
+		std::vector<Scalar> samples;
+
+
+	public:
+
+		/** ctor */
+		template <typename Distribution> LUT(const Distribution dist, const Scalar min, const Scalar max, const int numSamples) :
+			min(min), max(max), diff(max-min), numSamples(numSamples) {
+
+			buildLUT(dist);
+
+		}
+
+		/** get the probability of val from the LUT */
+		Scalar getProbability(const Scalar val) const {
+			int idx = ((val - min) * numSamples / diff);
+			idx = Math::clamp(0, numSamples-1, idx);
+			return samples[idx];
+		}
+
+	private:
+
+		/** build the look-up-table */
+		template <typename Distribution> void buildLUT(const Distribution dist) {
+
+			samples.resize(numSamples);
+			for (int idx = 0; idx < numSamples; ++idx) {
+				const Scalar val = min + (idx * diff / numSamples);
+				samples[idx] = dist.getProbability(val);
+			}
+
+		}
+
+	};
+
+}
+
+#endif // LUT_H