2. Collision Theory and Logic
Chapter 5
Collision Theory and Logic

3. Objectives Use game design software to create a playable video game.
Integrate animated objects into a video game.
Create sound and music effects in a video game.
Describe basic computer logic.
Build applied mathematics logic statements.
List features of object-oriented programming.

4. Logic
The first concept of designing and programming a video game is an action– reaction relationship
Programmers use logic statements to break down these action–reaction relationships
You will need to understand the five basic operators of a programming language: IF, THEN, AND, OR, and ELSE

5. Logic (Continued)
A logic statement tests a condition and determines an action based on the result
An IF…THEN statement is the most basic example of a logic statement
When programming a video game, the formal term for an action is a condition
An event is a change that occurs when a condition is met

6. Logic (Continued)
Programming for the user interface uses listeners and triggers
A listener is programming that directs the computer to check or listen for a mouse click, key press, or other input from the user
A trigger is programming for when a condition is met that a series of actions will begin
In a logic statement, the trigger is the IF and the actions it initiates are the THEN

7. Logic (Continued)
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8. Logic (Continued)
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9. Logic (Continued)
The next step in basic programming is to add multiple actions or multiple reactions to logic statements
This is done using the AND and OR operators
The AND operator will join two or more outcomes for a given condition or action
The OR operator allows multiple results to take place under a given condition or event

10. Logic (Continued)
The ELSE operator describes what will happen if a certain action or reaction does not take place
The ELSE operator works like a true/false test
If the condition is true, the THEN events are initiated
If the condition is false, the ELSE events are initiated

11. Collision Theory
Collision theory deals with an object running into or hitting another object
When objects collide in a game, the movements, animations, and events must provide an illusion of reality
Interactivity is how one object behaves when it encounters another object
A collision statement must exist for each object the player touches for interaction

12. Programming with Collision Theory
When the computer recognizes a collision, it sets into action the events programmed by logic statements
Games Factory 2 is an object-oriented, game development software that can be used to program a collision condition and events
To make objects appear solid, the programmer needs to add some realistic effects to the collision
Collision theory controls almost every interaction in video game action

13. Programming with Collision Theory (Continued)
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14. Writing a Logic Statement
Pseudo code is similar to computer code
It helps by breaking down the interactions into the logical steps
Another benefit of pseudo code is that it can be used as the structure for many different computer languages
The programming words and symbols and their arrangement is called syntax

15. Pseudo code

16. Writing a Logic Statement (Continued)
Most high-level programming languages use syntax that reads like a regular sentence
Definition subroutines are called objects
Objects are defined by their attributes and properties
Actions are how an object reacts to input or interacts with other objects
Methods are the actions or verbs used in syntax

17. Writing a Logic Statement (Continued)
Variables are small information storage containers
Text stored in a variable is called a string
Arrays are a common data structure used to store and manipulate data
There are four different loop commands common to most languages: LOOP, FOR, DO WHILE, and DO UNTIL

18. Writing a Logic Statement (Continued)
Programmers create the names for the objects, actions, methods, and variables used
Persistence means that something continues to exist after the event that caused it has ended
Modules are separate units of programming that perform one function and contain all the information needed to execute that function

19. Writing a Logic Statement (Continued)
The programming language used to code the game will do nothing on the computer until it is compiled into machine code
The choice of programming language used has more to do with a programmer’s likes and dislikes than functionality
To create a module within a game, it is important to plan all the parts of the operation using a flowchart or other organizational tool

20. Writing a Logic Statement (Continued)
An algorithm is a computer script that performs the steps needed to solve a problem
Structure is the syntax and logic form of the programming language
Sequence is the predetermined order or steps the computer program will follow
An iteration is a single run through a programming loop

21. The Games Factory 2
The Games Factory 2 (TGF2) is a powerful game engine that uses object-oriented programming to make two-dimensional video games
Two extremely beneficial features of TGF2 are that the game engine
Runs very well on a standard PC
Is very user friendly

22. Think about a video game you like to play
Think about a video game you like to play. What type of user inputs does the game accept?
Describe a collision you have seen in a video game that did not seem realistic. How might the game be changed to make the collision seem more realistic?