src/jelly/PointMass.cpp

   1 /*
   2  * Copyright (c) 2007 Walaber
   3  * Modified by Ketmar // Invisible Vector
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a copy
   6  * of this software and associated documentation files (the "Software"), to deal
   7  * in the Software without restriction, including without limitation the rights
   8  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9  * copies of the Software, and to permit persons to whom the Software is
  10  * furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included in
  13  * all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  18  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21  * THE SOFTWARE.
  22  */
  23 #include "PointMass.h"
  24
  25
  26 namespace  JellyPhysics {
  27
  28 PointMass::PointMass (float mass, const Vector2 &pos) {
  29   setMass(mass);
  30   Position = pos;
  31   Velocity = Force = Vector2::Zero;
  32   lastElapsed = 0;
  33   lastElapMass = 1;
  34 }
  35
  36
  37 void PointMass::setMass (float mass) {
  38   mInfMass = (mass == 0.0f || isinf(mass));
  39   mMass = (!mInfMass ? mass : 0.0f);
  40 }
  41
  42
  43 void PointMass::integrateForce (float elapsed) {
  44   if (!mInfMass) {
  45     if (lastElapsed != elapsed) {
  46       lastElapsed = elapsed;
  47       lastElapMass = elapsed/mMass;
  48     }
  49     Velocity += Force*lastElapMass;
  50     Position += Velocity*elapsed;
  51   }
  52   Force = Vector2::Zero;
  53 }
  54
  55 }