Office of Digital Humanities

Game Loop Stack Assignment

In class we went through the process of creating constant motion elements in a stack using a "game loop", a special set of scripts in the stack and card that constantly send an updateScreen message to the card.

The first example we looked at was the "blastoff" stack, in which we built a simple animated rocket.

We used the same basic framework to create a side-scrolling animation that incorporated a constant-motion scrolling background in addition to a moving vehicle that can accelerate and decelerate. The key is to use the updateScreen handler in the card script to update the object motion on the card.

Using the blastoff.livecode stack and the sideScroller.livecode stack as examples, create your own stack with constant motion objects in it. Successful completion of this assignment will require that you study, understand and modify the card and stack scripts used in the models. You should pay special attention to the updateScreen handler in the cards scripts of the two stacks.

Modify your stack from the models in at least three of the following ways:

• Find your own background and scrolling scenery images and substitute them into the example stack.
• Use a different vehicle (or animal or boat or other) image for the moving object.
• Add a sound effect for the vehicle sound and play it as a looping audio clip.
• Make the scrolling go in a different direction. For example, could you make a simple scrolling race track stack where the track scrolled from top to bottom and the vehicle moved from side to side in order to make the curves?
• Other motion as desired. (E.g., vehicle vibrations, birds flying through the scene, obstacles moving through that your vehicle must avoid, etc.)
• Change the way the vehicle is controlled. For example, instead of moving it on mouseDown or mouseUp, move it using the arrow keys or with a set of controller buttons. (Imagine a gas pedal and break buttons, e.g.)

Test your stack on a simulator or mobile device and be prepared to demonstrate it to the instructor. Turn your stack into the Application Drop folder on the DigHT 310 server by the next class period.