Initial commit: Final state of the master project

Research/core/Util/TransferFunction.h

@@ -0,0 +1,71 @@
+#pragma once
+#include "../Defines.h"
+#include <vector>
+#include <algorithm>
+#include "../MathHelper.h"
+
+template<typename T>
+class TransferFunction
+{
+public:
+	struct Node
+	{
+		unsigned32 value;
+		float opacity;
+		T material;
+
+		Node(unsigned32 value, float opacity, T mat) : value(value), opacity(opacity), material(mat) {}
+		Node(unsigned32 value) : value(value), opacity(0), material(T()) {}
+	};
+
+	struct NodeCompare { bool operator()(const Node& a, const Node& b) { return a.value < b.value; } };
+
+	TransferFunction()
+	{
+	}
+
+	~TransferFunction() { mFunction.clear(); }
+
+	void AddNode(unsigned32 value, float opacity, T mat)
+	{
+		Node node(value, opacity, mat);
+		auto pos = LowerBound(node);
+		if (pos != mFunction.end() && pos->value == value)
+			mFunction[pos - mFunction.begin()] = node;
+		else
+			mFunction.insert(pos, node);
+	}
+
+	template<typename Interpolator>
+	void Evaluate(unsigned32 value, float& outOpacity, T& outMat, Interpolator interpolator) const
+	{
+		Node node(value);
+		// Set default values
+		outOpacity = 1.f;
+		outMat = T();
+		// Find the current node
+		auto pos = LowerBound(node);
+		if (pos == mFunction.end()) return;
+		
+		Node after = *pos;
+		if (pos == mFunction.begin())
+		{
+			outOpacity = after.opacity;
+			outMat = after.material;
+			return;
+		}
+		pos--;
+		Node before = *pos;
+		float t = float(value - before.value) / float(after.value - before.value);
+		outMat = interpolator(before.material, after.material, t);
+		outOpacity = MathHelper::lerp(t, before.opacity, after.opacity);
+	}
+private:
+	typename std::vector<Node>::const_iterator LowerBound(const Node& node) const 
+	{
+		return std::lower_bound(mFunction.begin(), mFunction.end(), node, NodeCompare());
+	}
+
+	std::vector<Node> mFunction;
+};
+