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2020-08-04 13:13:01 -04:00

138 lines
3.2 KiB
C++

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//=============================================================================//
#ifndef LERP_FUNCTIONS_H
#define LERP_FUNCTIONS_H
#ifdef _WIN32
#pragma once
#endif
template <class T>
inline T LoopingLerp(float flPercent, T flFrom, T flTo) {
T s = flTo * flPercent + flFrom * (1.0f - flPercent);
return s;
}
template <>
inline float LoopingLerp(float flPercent, float flFrom, float flTo) {
if (fabs(flTo - flFrom) >= 0.5f) {
if (flFrom < flTo)
flFrom += 1.0f;
else
flTo += 1.0f;
}
float s = flTo * flPercent + flFrom * (1.0f - flPercent);
s = s - (int)(s);
if (s < 0.0f) s = s + 1.0f;
return s;
}
template <class T>
inline T Lerp_Hermite(float t, const T& p0, const T& p1, const T& p2) {
T d1 = p1 - p0;
T d2 = p2 - p1;
T output;
float tSqr = t * t;
float tCube = t * tSqr;
output = p1 * (2 * tCube - 3 * tSqr + 1);
output += p2 * (-2 * tCube + 3 * tSqr);
output += d1 * (tCube - 2 * tSqr + t);
output += d2 * (tCube - tSqr);
return output;
}
template <class T>
inline T Derivative_Hermite(float t, const T& p0, const T& p1, const T& p2) {
T d1 = p1 - p0;
T d2 = p2 - p1;
T output;
float tSqr = t * t;
output = p1 * (6 * tSqr - 6 * t);
output += p2 * (-6 * tSqr + 6 * t);
output += d1 * (3 * tSqr - 4 * t + 1);
output += d2 * (3 * tSqr - 2 * t);
return output;
}
inline void Lerp_Clamp(int val) {}
inline void Lerp_Clamp(float val) {}
inline void Lerp_Clamp(const Vector& val) {}
inline void Lerp_Clamp(const QAngle& val) {}
// If we have a range checked var, then we can clamp to its limits.
template <class T, int minValue, int maxValue, int startValue>
inline void Lerp_Clamp(
CRangeCheckedVar<T, minValue, maxValue, startValue>& val) {
val.Clamp();
}
template <>
inline QAngle Lerp_Hermite<QAngle>(float t, const QAngle& p0, const QAngle& p1,
const QAngle& p2) {
// Can't do hermite with QAngles, get discontinuities, just do a regular
// interpolation
return Lerp(t, p1, p2);
}
template <class T>
inline T LoopingLerp_Hermite(float t, T p0, T p1, T p2) {
return Lerp_Hermite(t, p0, p1, p2);
}
template <>
inline float LoopingLerp_Hermite(float t, float p0, float p1, float p2) {
if (fabs(p1 - p0) > 0.5f) {
if (p0 < p1)
p0 += 1.0f;
else
p1 += 1.0f;
}
if (fabs(p2 - p1) > 0.5f) {
if (p1 < p2) {
p1 += 1.0f;
// see if we need to fix up p0
// important for vars that are decreasing from p0->p1->p2 where
// p1 is fixed up relative to p2, eg p0 = 0.2, p1 = 0.1, p2 = 0.9
if (abs(p1 - p0) > 0.5) {
if (p0 < p1)
p0 += 1.0f;
else
p1 += 1.0f;
}
} else {
p2 += 1.0f;
}
}
float s = Lerp_Hermite(t, p0, p1, p2);
s = s - (int)(s);
if (s < 0.0f) {
s = s + 1.0f;
}
return s;
}
// NOTE: C_AnimationLayer has its own versions of these functions in
// animationlayer.h.
#endif // LERP_FUNCTIONS_H