b2dlite/bbody.d

   1 /*
   2  * Copyright (c) 2006-2007 Erin Catto http://www.gphysics.com
   3  *
   4  * Permission to use, copy, modify, distribute and sell this software
   5  * and its documentation for any purpose is hereby granted without fee,
   6  * provided that the above copyright notice appear in all copies.
   7  * Erin Catto makes no representations about the suitability
   8  * of this software for any purpose.
   9  * It is provided "as is" without express or implied warranty.
  10  */
  11 module b2dlite.bbody;
  12
  13 import iv.vmath;
  14 import b2dlite.mathutils;
  15
  16
  17 class Body {
  18 public:
  19   Vec2 position;
  20   VFloat rotation;
  21
  22   Vec2 velocity;
  23   VFloat angularVelocity;
  24
  25   Vec2 force;
  26   VFloat torque;
  27
  28   Vec2 width;
  29
  30   VFloat friction;
  31   VFloat mass, invMass;
  32   VFloat I, invI;
  33
  34 public:
  35   this () {
  36     position.set(VFloatNum!(0.0), VFloatNum!(0.0));
  37     rotation = VFloatNum!(0.0);
  38     velocity.set(VFloatNum!(0.0), VFloatNum!(0.0));
  39     angularVelocity = VFloatNum!(0.0);
  40     force.set(VFloatNum!(0.0), VFloatNum!(0.0));
  41     torque = VFloatNum!(0.0);
  42     friction = VFloatNum!(0.2);
  43
  44     width.set(VFloatNum!(1.0), VFloatNum!(1.0));
  45     mass = VFloat.max;
  46     invMass = VFloatNum!(0.0);
  47     I = VFloat.max;
  48     invI = VFloatNum!(0.0);
  49   }
  50
  51   void set() (in auto ref Vec2 w, VFloat m) {
  52     position.set(VFloatNum!(0.0), VFloatNum!(0.0));
  53     rotation = VFloatNum!(0.0);
  54     velocity.set(VFloatNum!(0.0), VFloatNum!(0.0));
  55     angularVelocity = VFloatNum!(0.0);
  56     force.set(VFloatNum!(0.0), VFloatNum!(0.0));
  57     torque = VFloatNum!(0.0);
  58     friction = VFloatNum!(0.2);
  59     width = w;
  60     mass = m;
  61     if (mass < VFloat.max) {
  62       invMass = VFloatNum!(1.0)/mass;
  63       I = mass*(width.x*width.x+width.y*width.y)/VFloatNum!(12.0);
  64       invI = VFloatNum!(1.0)/I;
  65     } else {
  66       invMass = VFloatNum!(0.0);
  67       I = VFloat.max;
  68       invI = VFloatNum!(0.0);
  69     }
  70   }
  71
  72   void AddForce() (in auto ref Vec2 f) { pragma(inline, true); force += f; }
  73
  74   int opCmp() (Body b) pure const nothrow @trusted @nogc {
  75     if (b is null) return 1;
  76     if (b is this) return 0;
  77     if (cast(size_t)cast(void*)this < cast(size_t)cast(void*)b) return -1;
  78     if (cast(size_t)cast(void*)this > cast(size_t)cast(void*)b) return 1;
  79     return 0;
  80   }
  81 }