Use and Programming Model
| public void act { setLocation (getX + 4, getY); setRotation (getRotation + 2); } |
| An example of a simple act method in Greenfoot |
| Actor a = getOneIntersectingObject(Asteroid.class); if (a != null) { // we have hit an asteroid! explode; } |
| An example of simple collision detection |
The Greenfoot programming model consists of a World class (represented by a rectangular screen area) and any number of actor objects that are present in the world and can be programmed to act independently. The world and actors are represented by Java objects and defined by Java classes. Greenfoot offers methods to easily program these actors, including method for movement, rotation, changes of appearance, collision detection, etc.
Programming in Greenfoot at its most basic consists of subclassing two built-in classes, World and Actor. An instance of the world subclass represents the world in which Greenfoot execution will occur. Actor subclasses are objects that can exist and act in the world. An instance of the world subclass is automatically created by the environment.
Execution in Greenfoot consists of a built-in main loop that repeatedly invokes each actor's act method. Programming a scenario, therefore, consists mainly of implementing act methods for the scenario's actors. Implementation is done in standard Java. Greenfoot offers API methods for a range of common tasks, such as animation, sound, randomisation, and image manipulation. All standard Java libraries can be used as well, and sophisticated functionality can be achieved.
Read more about this topic: Greenfoot
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