Movement

• Going deeper into different ways of moving in arcade games
• Aiding the transition to GameMaker using Scratch as a scaffold and common language.
• Avoiding Collision Detection as much as possible (except stop)

Teachers Notes

1. GameMaker is difficult for Y8 they find the concept of defining an Event difficult. Less committed students struggle to navigate around the environment and work out which code is on which object or which event.
2. Yet GM produces better looking games and is a real draw to the more able students
3. GM is a way of introducing the concept of Objects Instances which are central to Object Oriented Programming.

Progression from PG Online Units (Y7)

• Player movement is introduced as simple step based with keyboard delay and repeat.
• “Smoother” movement is introduced in L2 with a forever loop to produce a kind of Event Listener that responds immediately with no keyboard delay. But the movement relies on the key being held down.
• Enemy movement uses forever move and if on edge bounce
• So Y8 can delve much deeper into more interesting movement
• Jumping in PGOnline is a simplfied to a linear jump
• Shooting is left or right and on one slide
• FPS uses mouse control of cross hairs

Step Based Moves

• move
• change x by
• Event listener

Speed Based Movement

Using absolute directions N S E W

• Moving without stopping
• For player (keypress event) or enemy (create event)
• Varying speed eg. to make the game more difficult.

Relative Directions (Left and Right)

Left and Right a few degrees for each keypress

Transformations of Sprite

• Flip
• Rotate
• Change Image (Celebrate, burn)

Edge of the screen

• Stop (Wall): If (x > screen_width) speed=0
• Wrap
• Bounce

Mouse Movement

Momentum

Gravity

Scroller

Extras

Some more advanced techniques

Getting In Close

Getting closer to the wall or the floor than the step/speed size of the Player

Shoot

FPS 2D or 3D?