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// MIT License
// Copyright (c) 2019 Erin Catto
// 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 B2_ROPE_H
#define B2_ROPE_H
#include "b2_api.h"
#include "b2_math.h"
class b2Draw;
struct b2RopeStretch;
struct b2RopeBend;
enum b2StretchingModel
{
b2_pbdStretchingModel,
b2_xpbdStretchingModel
};
enum b2BendingModel
{
b2_springAngleBendingModel = 0,
b2_pbdAngleBendingModel,
b2_xpbdAngleBendingModel,
b2_pbdDistanceBendingModel,
b2_pbdHeightBendingModel,
b2_pbdTriangleBendingModel
};
///
struct B2_API b2RopeTuning
{
b2RopeTuning()
{
stretchingModel = b2_pbdStretchingModel;
bendingModel = b2_pbdAngleBendingModel;
damping = 0.0f;
stretchStiffness = 1.0f;
bendStiffness = 0.5f;
bendHertz = 1.0f;
bendDamping = 0.0f;
isometric = false;
fixedEffectiveMass = false;
warmStart = false;
}
b2StretchingModel stretchingModel;
b2BendingModel bendingModel;
float damping;
float stretchStiffness;
float stretchHertz;
float stretchDamping;
float bendStiffness;
float bendHertz;
float bendDamping;
bool isometric;
bool fixedEffectiveMass;
bool warmStart;
};
///
struct B2_API b2RopeDef
{
b2RopeDef()
{
position.SetZero();
vertices = nullptr;
count = 0;
masses = nullptr;
gravity.SetZero();
}
b2Vec2 position;
b2Vec2* vertices;
int32 count;
float* masses;
b2Vec2 gravity;
b2RopeTuning tuning;
};
///
class B2_API b2Rope
{
public:
b2Rope();
~b2Rope();
///
void Create(const b2RopeDef& def);
///
void SetTuning(const b2RopeTuning& tuning);
///
void Step(float timeStep, int32 iterations, const b2Vec2& position);
///
void Reset(const b2Vec2& position);
///
void Draw(b2Draw* draw) const;
private:
void SolveStretch_PBD();
void SolveStretch_XPBD(float dt);
void SolveBend_PBD_Angle();
void SolveBend_XPBD_Angle(float dt);
void SolveBend_PBD_Distance();
void SolveBend_PBD_Height();
void SolveBend_PBD_Triangle();
void ApplyBendForces(float dt);
b2Vec2 m_position;
int32 m_count;
int32 m_stretchCount;
int32 m_bendCount;
b2RopeStretch* m_stretchConstraints;
b2RopeBend* m_bendConstraints;
b2Vec2* m_bindPositions;
b2Vec2* m_ps;
b2Vec2* m_p0s;
b2Vec2* m_vs;
float* m_invMasses;
b2Vec2 m_gravity;
b2RopeTuning m_tuning;
};
#endif
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