NeHe OpenGL Lesson40 - Rope Physics

 This sample shows us how to implement a complete physics simulation. The key point to build a simulation is to create a group of physics settings properly. During the simulation update, solve all the forces that the mass currently be applied. With the sum of the force, we could calculate the moment acceleration, update the accumulated velocity accordingly. With the eclipsed delta time, we could find the updated position (move distance = velocity * delta time). So we could get the correct moving equation. In addition to the proper physics settings, we also need to consider some constants that are experienced value. And we need to also take care of the maximum delta time. All those stuff will make the physics simulation work realistic or not. Of course, we need some tune working for those settings and constants to get more cool effect. 

In this sample, the rope physics represented with a sequence of mass particles that bounded with springs. During simulation update, all external forced that applied on the mass particles will be collected, then a new velocity calculated based on the current acceleration and delta time. So a new position calculated by summing the current moving distance. This article was full of physics theory, and physics settings. The OpenGL render part was very easy, just draw some lines and a quad.

 

The full source code could be found here.