 |
|
Physics Based Animation
This program simulates collision of spheres within a cube and is based on Chris Hecker's game developer mag article. The coefficient for damping, the time step, and the ball data are read off a configuration file.
Pseudocode (see [1]) :
while(simulating) { DeltaTime = CurrentTime - LastTime while(LastTime < CurrentTime) { calculate all forces and torques compute linear and angular accelerationsintegrate accelerations and velocities over DeltaTimeif(objects are interpenetrating) {subdivide DeltaTime} else {if(objects are colliding) {resolve collisions using Eqs. 8 and 9}LastTime = LastTime + DeltaTimeDeltaTime = CurrentTime - LastTimeupdate positions and velocities}}draw objects in current positions}
Issues: Sometimes (towards the end) balls get struck in the corners of walls- we do not back off and reduce the timestep as we should ideally, thus if the ball has penetrated,it gets stuck to the corner of a wall. Angular momentum conservation has not been implemented.
To start the simulation, press a. To start the simulation and save it to a file, press f. 500 frames are rendered and saved.
References:
[1] Chris Hecker in his game developer mag article.
[2] The Book Physics for Game Developers was also used.
| Send feedback regarding this page to [email protected] |
Last Modified: 11/10/2003 |