godot/core/interpolated_property.h
lawnjelly 18c01b21e5 Physics Interpolation - Add InterpolatedProperty
And add some basic interpolated properties to Camera.
2025-04-07 08:19:00 +01:00

109 lines
4.1 KiB
C++

/**************************************************************************/
/* interpolated_property.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**************************************************************************/
#ifndef INTERPOLATED_PROPERTY_H
#define INTERPOLATED_PROPERTY_H
struct Vector2;
namespace InterpolatedPropertyFuncs {
float lerp(float p_a, float p_b, float p_fraction);
Vector2 lerp(const Vector2 &p_a, const Vector2 &p_b, float p_fraction);
} //namespace InterpolatedPropertyFuncs
// This class is intended to reduce the boiler plate involved to
// support custom properties to be physics interpolated.
template <class T>
class InterpolatedProperty {
// Only needs interpolating / updating the servers when
// curr and prev are different.
bool _needs_interpolating = false;
T _interpolated;
T curr;
T prev;
public:
// FTI depends on the constant flow between current values
// (on the current tick) and stored previous values (on the previous tick).
// These should be updated both on each tick, and also on resets.
void pump() {
prev = curr;
_needs_interpolating = false;
}
void reset() { pump(); }
void set_interpolated_value(const T &p_val) {
_interpolated = p_val;
}
const T &interpolated() const { return _interpolated; }
bool needs_interpolating() const { return _needs_interpolating; }
bool interpolate(float p_interpolation_fraction) {
if (_needs_interpolating) {
_interpolated = InterpolatedPropertyFuncs::lerp(prev, curr, p_interpolation_fraction);
return true;
}
return false;
}
operator T() const {
return curr;
}
bool operator==(const T &p_o) const {
return p_o == curr;
}
bool operator!=(const T &p_o) const {
return p_o != curr;
}
InterpolatedProperty &operator=(T p_val) {
curr = p_val;
_interpolated = p_val;
_needs_interpolating = true;
return *this;
}
InterpolatedProperty(T p_val) {
curr = p_val;
_interpolated = p_val;
pump();
}
InterpolatedProperty() {
// Ensure either the constructor is run,
// or the memory is zeroed if using a fundamental type.
_interpolated = T{};
curr = T{};
prev = T{};
}
};
#endif // INTERPOLATED_PROPERTY_H