ContactSolver.hpp

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/*
 * Original work Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
 * Modified work Copyright (c) 2017 Louis Langholtz https://github.com/louis-langholtz/PlayRho
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
 
#ifndef PLAYRHO_DYNAMICS_CONTACTS_CONTACTSOLVER_HPP
#define PLAYRHO_DYNAMICS_CONTACTS_CONTACTSOLVER_HPP
 
#include <PlayRho/Common/Math.hpp>
 
namespace playrho {
 
class StepConf;
 
namespace d2 {
 
class VelocityConstraint;
class PositionConstraint;
class BodyConstraint;
 
struct PositionSolution
{
    Position pos_a; 
    Position pos_b; 
    Length min_separation; 
};
 
inline PositionSolution operator+ (PositionSolution lhs, PositionSolution rhs)
{
    return PositionSolution{
        lhs.pos_a + rhs.pos_a,
        lhs.pos_b + rhs.pos_b,
        lhs.min_separation + rhs.min_separation
    };
}
 
inline PositionSolution operator- (PositionSolution lhs, PositionSolution rhs)
{
    return PositionSolution{
        lhs.pos_a - rhs.pos_a,
        lhs.pos_b - rhs.pos_b,
        lhs.min_separation - rhs.min_separation
    };
}
 
} // namespace d2
 
struct ConstraintSolverConf
{
    ConstraintSolverConf& UseResolutionRate(Real value) noexcept;
    
    ConstraintSolverConf& UseLinearSlop(Length value) noexcept;
    
    ConstraintSolverConf& UseAngularSlop(Angle value) noexcept;
    
    ConstraintSolverConf& UseMaxLinearCorrection(Length value) noexcept;
    
    ConstraintSolverConf& UseMaxAngularCorrection(Angle value) noexcept;
    
    Real resolutionRate = Real(0.2);
    
    Length linearSlop = DefaultLinearSlop;
    
    Angle angularSlop = DefaultAngularSlop;
    
    Length maxLinearCorrection = DefaultLinearSlop * Real{20};
    
    Angle maxAngularCorrection = DefaultAngularSlop * Real{4};
};
 
inline ConstraintSolverConf& ConstraintSolverConf::UseResolutionRate(Real value) noexcept
{
    resolutionRate = value;
    return *this;
}
 
inline ConstraintSolverConf& ConstraintSolverConf::UseLinearSlop(Length value) noexcept
{
    linearSlop = value;
    return *this;
}
 
inline ConstraintSolverConf& ConstraintSolverConf::UseAngularSlop(Angle value) noexcept
{
    angularSlop = value;
    return *this;
}
 
inline ConstraintSolverConf& ConstraintSolverConf::UseMaxLinearCorrection(Length value) noexcept
{
    maxLinearCorrection = value;
    return *this;
}
 
inline ConstraintSolverConf& ConstraintSolverConf::UseMaxAngularCorrection(Angle value) noexcept
{
    maxAngularCorrection = value;
    return *this;
}
 
inline ConstraintSolverConf GetDefaultPositionSolverConf()
{
    return ConstraintSolverConf{}.UseResolutionRate(Real(0.2));
}
 
inline ConstraintSolverConf GetDefaultToiPositionSolverConf()
{
    // For solving TOI events, use a faster/higher resolution rate than normally used.
    return ConstraintSolverConf{}.UseResolutionRate(Real(0.75));
}
 
ConstraintSolverConf GetRegConstraintSolverConf(const StepConf& conf) noexcept;
 
ConstraintSolverConf GetToiConstraintSolverConf(const StepConf& conf) noexcept;
 
namespace GaussSeidel {
 
Momentum SolveVelocityConstraint(d2::VelocityConstraint& vc);
 
d2::PositionSolution SolvePositionConstraint(const d2::PositionConstraint& pc,
                                     const bool moveA, const bool moveB,
                                     ConstraintSolverConf conf);
 
} // namespace GaussSidel
 
} // namespace playrho
 
#endif // PLAYRHO_DYNAMICS_CONTACTS_CONTACTSOLVER_HPP