Simulation of Water Droplets using Metaballs on mobile phones

Abstract

In the game Hydrotilt, the player controls a water droplet that consists of metaballs. This droplet does not have all the physical abilities of a water droplet in the game. For a newer version of Hydrotilt meant to run on mobile phones, Codeglue seeks for a realistic water droplet simulation using metaballs. Earlier researches of water droplet simulation used high computational resources device. Mobile phones on the other hand are low resources devices. Therefore, in the scope of this thesis we implemented in an experiment set-up a simulation of water droplets using metaballs for mobile phones. In this implementation, you have two kinds of water droplets. The first one is a static water droplet that waits until it is close enough to another droplet for merging. The other kind of droplet is a moving water droplet. This droplet moves according to the tilt of the mobile phone just like in the game Hydrotilt. Furthermore, metaballs need another algorithm to be able to generate the surface. In our implementation, two algorithms were used for that: octree and marching cube algorithm. Octree is slower than the marching cube algorithm, but needs less memory which is one of the low resources on mobile phones. In the simulation of the water droplet, the moving water droplet will change its shape while moving from a sphere-like shape to a water droplet like shape. Next to this, there are two techniques implemented to calculate the movement of the droplet. The first one is a following one that behaves like a spring and the second one is an interpolation of the movement. Testing of the experiment set-up showed that the simulation runs successfully on mobile phones. Furthermore, the testing also showed that there is a tradeoff between visual graphics of the water droplets and the performance. Better visual graphics (for example through high resolution) results in lower performance and for high performance the visually of the droplet needs to be reduced.