1. Tank Game
Int 10
Unit 3 – Game Maker

2. Unit Overview Install GameMaker on H: GameMaker Terminology
Introduction to GM(Tank Game tutorial)
Evaluating Video Games
Planning Video Games
Make Your Own

3. GameMaker Terminology
rooms:
provide the 2d space used to make game levels and worlds.
backgrounds:
An image, tile, colour or combination of the three that represents a room
objects:
Interactive elements of the game/ room
sprites:
Images that are usually used to represent objects.

4. GameMaker Terminology – Cont’d
Instances
An instance is a copy of a Game Maker object that is created during runtime.
sounds:
In various formats can be loaded and played in Game Maker.
scripts:
A script itself is a bit of GML code that can be called either directly from GML in the Execute Script action of an object.

5. Tank Game Tutorial Steps to create game:
Create rooms, backgrounds, sprites and objects
Make the tank move
Make the tank shoot in the right direction
Destroy enemies and bullets
Make enemies MORE POWERFUL!

6. Naming Sprites, Sounds & Objects
Name every:
sprite  spr_XXX
sound  snd_XXX
Object  obj_XXX
Imagine for example that you have a sprite called "Bullet", an object called "Bullet" and a sound called "Bullet".
Do use letters, numbers and underscores when making a name.
Do Not use spaces or weird characters like slashes, asterisks, dollar signs, ampersands, and similar.
Also, don't start with a number, use it only later in the name.

7. Step 1- Set up the Game area
Start Game Maker and create 4 rooms where the action will happen:
Title, lvl1, lvl2, lvl3, end rooms
Click the 'Add Room' icon
Choose a background colour
In settings, make the room caption the name of the room

8. Step 2 - Add In the Sprites
Click the 'Add Sprite' icon
Name it spr_tank
Click Load Sprite, and find the tank image.
Repeat steps for enemy tank, bullet, and wall sprites
Find sprites in resources packs or on line

9. Step 2 - Add In the Sprites
For tank, enemy tank, and bullet
Use the sprite editor in GM
Make sure the sprite canvas has the same height and width
Transform  resize canvas (unlock aspect ratio)
Modify Mask
Full image
ellipse
Center Origin
For wall sprite
Leave origin x=0, y=0
Modify mask
Automatic
precise

10. Step 2 - Add In the Sprites
For spr_tank
We need to also create right, down, and left tank sprites
Right click spr_tank
Duplicate
Rename spr_tank_r(ight)
Sprite editor
Transform  rotate (90o to the right)
Repeat for spr_tank_d(own) and spr_tank_l(eft)

11. Step 3 - Create the objects
Click the Add Object icon
Name it obj_tank
Choose the tank sprite to represent the object
Only add spr_tank (there should only be one tank object!)
don't make it solid.
Repeat for enemy tank and bullet
Add in a wall object. 
Name it obj_wall
choose the Wall sprite
make it solid.

12. Step 3 - and add them to the room
In the lvl1 room window click on the “objects” tab
Click on the add objects icon
Add 1 spr_tank and spr_enemy_tank
Add walls around the outside
Select objects and left click to add to room

13. Tank Game Tutorial Make the Tank Move
To make the tank move:
Make the tank jump to a new location when you press the key in that direction
Change the sprite to make the tank face the right direction
Event
Press Left Button
Actions
Jump to new position
Change sprites

14. Tank Game Tutorial Make the tank shoot in the right direction
This is a little more complex, here are the general steps:
Create a variable named “direction”
Assign a value to that variable for each direction button you press
Test for variable value when firing bullet.

15. Tank Game Tutorial Make the tank shoot in the right direction
In obj_player property pane
Event = create
Action = set variable (controls tab) to 90

16. Tank Game Tutorial Make the tank shoot in the right direction
Assign a value to that variable for each direction button you press (<left>, <up>, <right>, and<down>)

17. Tank Game Tutorial Make the tank shoot in the right direction
Test for variable value when firing bullet.
Event = press<Space>
Action = create moving instance (main 1)
Fill values in to dialogue box

18. Tank Game Tutorial Destroy enemies and bullets
If we don’t destroy bullets the continued creation of them will crash the computer
How can we destroy bullets?
Hint: put the code in the obj_bullet property pane and destroy “self”
How can we make enemies move?
What are some different ways to get the enemy to move?
To shoot? (you will have to create a separate obj_e_bullet)
How can we destroy enemies?

19. Finish Up The Game… Create a functioning game with: Setup
A starting screen with buttons
Themed images for backgrounds
Walls the player and enemies have to maneuver around (can’t go through)
A main player that:
Moves in all directions
Faces all directions it moves
Doesn’t move when the keys aren’t being pressed
Main player shoots:
In the direction it is facing
Destroyed when off screen/ or hits another objeccct
Only 4 projectiles at a time
Enemy object disappears when projectile hits it

20. Game Maker Challenge The game ends: “Die” after 3 hits
Go to losing screen
“Win” when all enemy objects from a level are gone
When all levels are completed (Minimum three)
In a wining room
Extensions (examples):
Make the enemy characters move around and shoots at main player
Have power up objects
Make player have multiple lives as well as multiple hits to die
Have it take multiple shots to destroy enemies
Other…