StarCall

Overview

In this lesson we will learn to make a game using the canvas, imagesprites, procedures, and timer.

New Concepts

Canvas:

A surface where you can put objects on a given location.

Image Sprite

An interactive image that can be put on a canvas. It reacts to collisions and touches.

Clock

Keeping track of timing and current time.

Let's Get Started

Designer

We will need:

• Canvas (x1)
• Image sprite (x3)

For the score counter:

• Horizontal layouts (x3)
• Labels (x4)
• Button (x1)
• Timer (x1)

For music:

• Player(x1)

##Specific Properties

• set screen orientation at Screen to be portrait
• set layer (z) for meteor sprite above the earth sprite
• set layer (z) for gameover sprite above all
• set timerInterval to a small number (i.e. 100) for responsive time tracking.

Mechanics

1. Initial Setup

   When you start the game, some settings need to be put into place:

   • Make sure game can run (not game over)
   • Establish basic speeds and music
   • Start the game (start calling meteors)

   

2. Score and time tracking

   Every time player stops a meteor, they get a point! also keep track how long they survived!

   • We will increase the score by 1 if the procedure is called.
   • Every time the timer ticks, we increase the time survived by the interval amount if the game is still going.

   

3. Sprite behavior

   • Spawn
   • Movement
   • Interaction

4. Game over!

   The player lost! Tell them.

   • If the meteor touches any of the bottom edges, the player lost!
   • Then we need to show them they lost
   • Stop the game/meteors from falling

   

5. Reset button

**Let them play the game again!**
* Reset the variables to original values
* Hide the game-over sprite
* Start the game

![reset](https://raw.githubusercontent.com/cppignite/lessons/master/StarCall/Img/resetting.PNG)

Stretch Goals

• More random behavior!
  • Angle of launch
  • Changing direction
    • Zig-zag
    • Slow curve
    • Simple change
  • Teleporting?
  • Slow-down/speed-up
• Difficulty Curve Tweaks (The Current difficulty is linear, It gets really hard!)
  • Easier
    • Square-root/logarithmic functions
    • Piece-wise linear functions (for example, from speed 1-10 growth is 0.5, 10-50 is 0.3, 50+ is 0.1)
  • Harder
    • exponential/power functions
• New features/mechanics!
  • Meteor size variable
  • New Type of meteors
  • Other interaction methods
  • Gyroscope for tilting
  • Long touches for special meteors

Media & Assets

1. Starsinthesky.jpg
2. fireball.png
3. game-over.png
4. Magellanic Clouds.mp3

5.  [earth.png](https://raw.githubusercontent.com/cppignite/lessons/master/StarCall/Media/earth.png)
   

External References

• Canvas
• Image Sprites
• Java Random

APK Download