## visualpython-users

 RE: [Visualpython-users] Collision detection with VPython From: Miles Jacobs - 2006-04-02 08:18:58 ```Found solution at http://python.matrix.jp/projects/pyogre/ode_test2.py. So now example 3 looks like this: # pyODE example 3: Collision detection # Originally by Matthias Baas. # Update by Miles Jacobs to make collision detection work with VPython. # With thanks to http://python.matrix.jp/projects/pyogre/ode_test2.py. import sys, os, random, time from math import * from visual import * import ode # geometric utility functions def scalp (vec, scal): vec[0] *= scal vec[1] *= scal vec[2] *= scal def length (vec): return sqrt (vec[0]**2 + vec[1]**2 + vec[2]**2) # create_box def create_box(world, space, density, lx, ly, lz): """Create a box body and its corresponding geom.""" # Create body body = ode.Body(world) M = ode.Mass() M.setBox(density, lx, ly, lz) body.setMass(M) # Set parameters for drawing the body body.shape = "box" body.boxsize = (lx, ly, lz) # Create a box geom for collision detection geom = ode.GeomBox(space, lengths=body.boxsize) geom.setBody(body) return body # drop_object def drop_object(): """Drop an object into the scene.""" global bodies, counter, objcount body = create_box(world, space, 1000, 1.0,1.0,1.0) body.setPosition((random.gauss(0,0.1),10.0,random.gauss(0,0.1))) theta = random.uniform(0,2*pi) ct = cos (theta) st = sin (theta) body.setRotation([ct, 0., -st, 0., 1., 0., st, 0., ct]) icecube = box(pos=body.getPosition(), axis=(ct,0.,st), length=1.0, height=1.0, width=1.0, color=(random.gauss(0,1),random.gauss(0,1),random.gauss(0,1))) bodies.append(body) cubes.append(icecube) counter=0 objcount+=1 # explosion def explosion(): """Simulate an explosion. Every object is pushed away from the origin. The force is dependent on the objects distance from the origin. """ global bodies for b in bodies: l=b.getPosition () d = length (l) a = max(0, 800000*(1.0-0.2*d*d)) l = [l[0] / 4, l[1], l[2] /4] scalp (l, a / length (l)) b.addForce(l) # pull def pull(): """Pull the objects back to the origin. Every object will be pulled back to the origin. Every couple of frames there'll be a thrust upwards so that the objects won't stick to the ground all the time. """ global bodies, counter for b in bodies: l=list (b.getPosition ()) scalp (l, -100000 / length (l)) b.addForce(l) if counter%60==0: b.addForce((0,100000,0)) # Collision callback def near_callback(args, geom1, geom2): """Callback function for the collide() method. This function checks if the given geoms do collide and creates contact joints if they do. """ # Check if the objects do collide contacts = ode.collide(geom1, geom2) # Create contact joints world,contactgroup = args for c in contacts: c.setBounce(0.2) c.setMu(5000) j = ode.ContactJoint(world, contactgroup, c) j.attach(geom1.getBody(), geom2.getBody()) ###################################################################### # Create a world object world = ode.World() world.setGravity( (0,-9.81,0) ) world.setERP(0.8) world.setCFM(1E-5) # Create a space object space = ode.Space() # Create a plane geom which prevent the objects from falling forever floor = ode.GeomPlane(space, (0,1,0), 0) ground=box(pos=(0,-0.1,0), width=20, height=0.1, length=20, color=color.white) # A list with ODE bodies and Visual objects to see the bodies bodies = [] cubes = [] # A joint group for the contact joints that are generated whenever # two bodies collide contactgroup = ode.JointGroup() # Some variables used inside the simulation loop fps = 25 dt = 1.0/fps running = True state = 0 counter = 0 objcount = 0 scene.autoscale=0 scene.forward=(-5,-5,-5) while(1): global counter, state counter += 1 if state==0: if counter==20: drop_object() if objcount==10: state=1 counter=0 # State 1: Explosion and pulling back the objects elif state==1: if counter==100: explosion() if counter>300: pull() if counter==500: counter=20 for b in range(len(bodies)): x,y,z = bodies[b].getPosition() R = bodies[b].getRotation() cubes[b].pos=(x,y,z) cubes[b].axis=R[0], R[3], R[6] cubes[b].up=R[1], R[4], R[7] print state, counter # Simulate n = 2 for i in range(n): # Detect collisions and create contact joints space.collide((world,contactgroup), near_callback) # Simulation step world.step(dt/n) # Remove all contact joints contactgroup.empty() rate(10) Miles. _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/ ```