How to make Angry Birds – part 2

Hello and welcome back to my blog!

This is the 2nd part of my series on how to make a game like Angry Birds by Rovio - and its been a while coming… You can read the first part here.

The Game

Ok, so here is the game so far; there are three demo levels to show the level progress system and some simple looking characters and block types. Apologies for the programmer art

Catch up

Ok, so last time I had covered how to draw the background graphics and made a start on how the world is going to be composed in terms of collision.

What I’m going to cover in this article is the physics part; stability and optimisations. The physics engine that I’ve created for this game is based on the technology I’ve discussed in my previous articles:

Physics engines for dummies
Collision detection for dummies
Speculative contacts – a continuous collision engine approach

Level

A level is defined as a bunch of instances of static rigid bodies and dynamic rigid bodies plus a visual layer which covers up the statics – I use this other layer because otherwise there would be a slight visible gap between adjacent static blocks, which we don’t want since the texture is supposed to be continuous.

A level must inherit the base class Code.Level. I’ve done this so I can predefine certain things about each level – such as the instance names for the hero characters, and the sling-shot which I need to reference in code.

Characters and blocks

Each of the two characters and every block used in the game are designed in the Flash IDE, and each of them references a base class that I’ve defined in the code. This is so that I can parse the children of a level at runtime and create the appropriate rigid bodies at the correct mapped locations for the physics engine.

Rigid-bodies

There are the following base classes (stone and wood use the same base class):

• HeroCharacter
• EnemyCharacter
• ProxyRectangleIce
• ProxyRectangle
• ProxyRectangleStatic
• ProxyTriangleStaticDown
• ProxyTriangleStaticUp

These are interpreted at level creation time, using a loop similar to this: [...]

Read more: How to make Angry Birds – part 2