72 lines
1.7 KiB
C++
72 lines
1.7 KiB
C++
#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;
|
|
};
|
|
|