From 973988b911037cef97f11c37f3a02018b45e2b98 Mon Sep 17 00:00:00 2001
From: Quantum <quantum2048@gmail.com>
Date: Fri, 21 Feb 2014 12:45:33 -0500
Subject: [PATCH] Added collision; bounces on collision.

---
 punyverse/entity.py | 19 ++++++++++++++++++-
 punyverse/game.py   |  4 ++++
 punyverse/world.py  |  2 +-
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/punyverse/entity.py b/punyverse/entity.py
index 50ef295..4b4ea87 100644
--- a/punyverse/entity.py
+++ b/punyverse/entity.py
@@ -1,5 +1,6 @@
-from punyverse.orbit import KeplerOrbit
+from math import sqrt
 
+from punyverse.orbit import KeplerOrbit
 from pyglet.gl import *
 
 
@@ -15,6 +16,9 @@ class Entity(object):
         x, y, z = self.location
         dx, dy, dz = self.direction
         self.location = x + dx, y + dy, z + dz
+    
+    def collides(self, x, y, z):
+        return False
 
 
 class Asteroid(Entity):
@@ -48,6 +52,7 @@ class Body(Entity):
         self.corona = kwargs.pop('corona', 0)
         self.last_tick = 0
         self.mass = kwargs.pop('mass', None)
+        self.radius = kwargs.pop('radius', None)
         self.world = kwargs.pop('world')
         orbit_distance = kwargs.pop('orbit_distance', 40000) + .0
         self.orbit_show = orbit_distance * 1.25
@@ -64,6 +69,18 @@ class Body(Entity):
             pitch, yaw, roll = self.rotation
             roll = (self.initial_roll + self.world.tick * self.rotation_angle) % 360
             self.rotation = pitch, yaw, roll
+    
+    def collides(self, x, y, z):
+        if self.radius is None:
+            return False
+        ox, oy, oz = self.location
+        dx, dy, dz = x - ox, y - oy, z - oz
+        distance = sqrt(dx*dx + dy*dy + dz*dz)
+        if distance > self.radius:
+            return False
+        return (ox + dx * self.radius / distance,
+                oy + dy * self.radius / distance,
+                oz + dz * self.radius / distance)
 
 
 class Satellite(Body):
diff --git a/punyverse/game.py b/punyverse/game.py
index 637ceb3..bea4452 100644
--- a/punyverse/game.py
+++ b/punyverse/game.py
@@ -351,6 +351,10 @@ class Applet(pyglet.window.Window):
                 self.world.tick += update
                 for entity in self.world.tracker:
                     entity.update()
+                    collision = entity.collides(c.x, c.y, c.z)
+                    if collision:
+                        self.speed *= -1
+                        c.move(self.speed * 12 * dt)
             else:
                 self.__time_accumulate += delta
 
diff --git a/punyverse/world.py b/punyverse/world.py
index ef388ff..e4f8194 100644
--- a/punyverse/world.py
+++ b/punyverse/world.py
@@ -190,7 +190,7 @@ class World(object):
             print 'Nothing to load for %s.' % name
             return
 
-        params = {'world': self, 'orbit_distance': orbit_distance}
+        params = {'world': self, 'orbit_distance': orbit_distance, 'radius': None if background else radius}
         if parent is None:
             type = Body
         else: