src/net/habraun/sd/EulerIntegrator.scala

   1 /*
   2         Copyright (c) 2009 Hanno Braun <hanno@habraun.net>
   3
   4         Licensed under the Apache License, Version 2.0 (the "License");
   5         you may not use this file except in compliance with the License.
   6         You may obtain a copy of the License at
   7
   8                 http://www.apache.org/licenses/LICENSE-2.0
   9
  10         Unless required by applicable law or agreed to in writing, software
  11         distributed under the License is distributed on an "AS IS" BASIS,
  12         WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13         See the License for the specific language governing permissions and
  14         limitations under the License.
  15 */
  16
  17
  18
  19 package net.habraun.sd
  20
  21
  22
  23 import math._
  24
  25
  26
  27 class EulerIntegrator extends Integrator {
  28
  29         def apply(t: Double, body: Body) = {
  30                 var velocity = body.velocity
  31
  32                 // Apply forces.
  33                 velocity += body.appliedForce / body.mass * t
  34                 body.resetForce
  35
  36                 // Apply impulses.
  37                 velocity += body.appliedImpulse / body.mass
  38                 body.resetImpulse
  39
  40                 // Solve movement constraints.
  41                 val constrainedXVelocity = if (body.xMovementAllowed) velocity.x else 0.0
  42                 val constrainedYVelocity = if (body.yMovementAllowed) velocity.y else 0.0
  43                 val constrainedVelocity = Vec2D(constrainedXVelocity, constrainedYVelocity)
  44
  45                 // Set new velocity.
  46                 body.velocity = constrainedVelocity
  47
  48                 // Set new position.
  49                 body.position = body.position + (body.velocity * t)
  50
  51                 body
  52         }
  53 }