Problem Set: Buttons

This section contains a number of selected problems for the Buttons section.

It is recommended that you review the problems, and complete a few before moving on to the next section.

Problem #1: Ducky Go Home

Create a ||sprites:sprite|| that looks like an alien spaceship, and ||controller:moves with buttons||.

Next, create an event that causes a ||sprites:projectile|| that looks like a duck to be created from the spaceship with a ||sprites:vy|| of 50 when the ||controller:A|| button is pressed.

Problem #2: Jump Man

Create a ||sprites:sprite|| to represent the main character in your game. Give the ||sprites:sprite|| an ||sprites:ay|| of 100 to represent the force of ||sprites:gravity||, and set the ||sprites:stay on screen|| flag to ||logic:true||. Make the character ||controller:move with buttons|| with a ||sprites:vx|| of 100 and a ||sprites:vy|| of 0, so that it can move along the bottom of the screen.

Next, create an event that causes the character to ‘jump,’ by setting the ||sprites:vy|| to -50 when the ||controller:A|| button is pressed.

Now, the character can move along the bottom of the screen and jump; all ready for your next hit platformer.

Problem #3: Coordinate Tracker

It is helpful to know where specific sprites are on the screen. The console.log can be very helpful when debugging your games, as it provides a consistent and easy location to store information without getting in the way of the game like ||game:game.splash|| or ||sprites:sprite.say||.

Create a ||sprites:sprite|| that ||controllers:moves with buttons||, and create an event that logs the ||sprites:sprite||‘s current position when the ||controller:B|| button is pressed. Make sure it is clear which value corresponds to which property; one way to do this would be by using the format x: 40, y: 80.

Problem #4: Inversion

Create a ||sprites:sprite|| to represent a princess with magical powers. Set it’s ||sprites:ay|| to 200, and the ||sprites:stay on screen|| flag to ||logic:true||. Make the character ||controller:move with buttons|| with a ||sprites:vx|| of 100 and a ||sprites:vy|| of 0, so that it can move along the bottom of the screen.

Create an event that occurs when the ||controller:A|| button is pressed. In it, you should do the following to the princess ||sprites:sprite||:

• Set the ||sprites:vy|| to 0, so that the ||sprites:sprite|| stops in place.
• Set the ||sprites:ay|| to itself times -1, so that it accelerates in the opposite direction.
• Invert the ||images:image|| of the sprite, using the following snippet (assuming the ||sprites:sprite|| is stored as ||variables:mySprite||)

mySprite.image.flipY();

With this, the ||controller:A|| button will use the princesses magic to swap gravity, and flip upside down.

Problem #5: Food Fight

Create four ||controller:controller button pressed|| events, one for each directional button.

Each of these events should create a food ||sprites:projectile|| that moves in the direction of the buttons: the ||controller:left|| button could create a strawberry that moves across the screen from right to left, the ||controller:up|| button could create an ice cream cone the moves from bottom to top, and so on.