Body.h

/*
    Copyright (c) 2013 Randy Gaul http://RandyGaul.net

    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 BODY_H
#define BODY_H

struct Shape;

// http://gamedev.tutsplus.com/tutorials/implementation/how-to-create-a-custom-2d-physics-engine-the-core-engine/
struct Body
{
  Body( Shape *shape_, uint32 x, uint32 y );

  void ApplyForce( const Vec2& f )
  {
    force += f;
  }

  void ApplyImpulse( const Vec2& impulse, const Vec2& contactVector )
  {
    velocity += im * impulse;
    angularVelocity += iI * Cross( contactVector, impulse );
  }

  void SetStatic( void )
  {
    I = 0.0f;
    iI = 0.0f;
    m = 0.0f;
    im = 0.0f;
  }

  void SetOrient( real radians );

  Vec2 position;
  Vec2 velocity;

  real angularVelocity;
  real torque;
  real orient; // radians

  Vec2 force;

  // Set by shape
  real I;  // moment of inertia
  real iI; // inverse inertia
  real m;  // mass
  real im; // inverse masee

  // http://gamedev.tutsplus.com/tutorials/implementation/how-to-create-a-custom-2d-physics-engine-friction-scene-and-jump-table/
  real staticFriction;
  real dynamicFriction;
  real restitution;

  // Shape interface
  Shape *shape;

  // Store a color in RGB format
  real r, g, b;
};

#endif // BODY_H