S60 3rd Edition SDK for Symbian OS
Example Applications Guide

OpenGL ES Rain Example

1. About this Example
2. Prerequisites
3. Design and Implementation

1. About this Example

This example demonstrates how to implement a particle engine. Particle systems are used in games to produce many effects such as snow, rain, smoke, sparks, explosions, and more. In fact, what looks like snowfall, raindrops, smoke or sparks is just a set of partially transparent textured rectangles moving through the scene.

This example can be extended to any kind of OpenGL ES application, but you might want to look at the other example applications as well for how to use other, different kinds of, OpenGL ES features.

Only classes used by this example are the basic UI framework baseclasses. Open GL ES itself is pure C method call API and doesn't use classes.

2. Prerequisites

To build and run this example you need to have the S60 SDK installed and working correctly on your computer. You also need basic understanding on how to build S60 applications.

To work with this example application you need basic understanding on how to build S60 applications and basic undestanding of how Symbian (or COE) UI and application framework works. Also basic knowledge on OpenGL or OpenGL ES is required if you wish to modify the example.

3. Design and Implementation

The trick is to make them behave like snow drops or smoke. For example, in the real world, raindrops fall since they are affected by gravity, smoke rises but is also affected by wind and dissolves after some time. The Rain example uses line primitives to render raindrops and their positions are governed by some equations and they are updated in each frame.

3.1 Capabilities

The application has capability NONE as it only needs the rights to execute and access to the screen.

3.2 ScalableUI

All Open GL ES examples support various screen modes. The examples also support changing the screen size while the application is running. Note that this support must be coded in the application and this code resides in the container's SizeChanged() method.

This inheritance list is sorted roughly, but not completely, alphabetically: