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 b2dlite.mathutils;
  14
  15
  16 class Body {
  17 public:
  18   Vec2 position;
  19   float rotation;
  20
  21   Vec2 velocity;
  22   float angularVelocity;
  23
  24   Vec2 force;
  25   float torque;
  26
  27   Vec2 width;
  28
  29   float friction;
  30   float mass, invMass;
  31   float I, invI;
  32
  33 public:
  34   this () {
  35     position.Set(0.0f, 0.0f);
  36     rotation = 0.0f;
  37     velocity.Set(0.0f, 0.0f);
  38     angularVelocity = 0.0f;
  39     force.Set(0.0f, 0.0f);
  40     torque = 0.0f;
  41     friction = 0.2f;
  42
  43     width.Set(1.0f, 1.0f);
  44     mass = float.max;
  45     invMass = 0.0f;
  46     I = float.max;
  47     invI = 0.0f;
  48   }
  49
  50   void Set() (in auto ref Vec2 w, float m) {
  51     position.Set(0.0f, 0.0f);
  52     rotation = 0.0f;
  53     velocity.Set(0.0f, 0.0f);
  54     angularVelocity = 0.0f;
  55     force.Set(0.0f, 0.0f);
  56     torque = 0.0f;
  57     friction = 0.2f;
  58     width = w;
  59     mass = m;
  60     if (mass < float.max) {
  61       invMass = 1.0f/mass;
  62       I = mass*(width.x*width.x+width.y*width.y)/12.0f;
  63       invI = 1.0f/I;
  64     } else {
  65       invMass = 0.0f;
  66       I = float.max;
  67       invI = 0.0f;
  68     }
  69   }
  70
  71   void AddForce() (in auto ref Vec2 f) { pragma(inline, true); force += f; }
  72
  73   int opCmp() (Body b) pure const nothrow @trusted @nogc {
  74     if (b is null) return 1;
  75     if (b is this) return 0;
  76     if (cast(size_t)cast(void*)this < cast(size_t)cast(void*)b) return -1;
  77     if (cast(size_t)cast(void*)this > cast(size_t)cast(void*)b) return 1;
  78     return 0;
  79   }
  80 }