MULT 110 Basic Game Programming I

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MULT 110Basic Game Programming I

• Conditionals

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Last Class

• Variables
• Expressions
• Operators
• Kinds?
• Increment and decrement?
• Assignment vs. equivalence?
• Comments
• Why?
• Single line vs. multi-line?

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Branching

• The very nature of interaction is branching from
  the straight and narrow path the timeline.
• Under one condition you may take one path and
  under another condition you may take another
  path.
• Branching and conditional execution are the same
  thing.

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If Statement

• if (expression)
• statement 1
• statement 2
• The expression must be something that can be
  judged true or false.
• If the expression is true, then all the
  statements between and are executed.
• If the expression is false, the statements inside
  the curly braces are not executed.

Statements lt Conditions / Loops lt If
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Expressions

• Each of these is an expression
• 7 gt 10
• 6 2 3
• GameOver
• true is a keyword in ActionScript
• Its value is 1
• false is a keyword in ActionScript
• Its value is 0

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Examples of Conditionals

• if (playerNum computerNum)
• playerWins
• output Hooray!! Player wins!
• The above statement provides for only one
  condition the numbers match

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Examples of Conditionals

• if (playerNum computerNum)
• playerWins
• output Hooray!! Player wins!
• else
• output Sorry. The computer wins.
• This statement provides for two conditions
  numbers match and numbers do not match.

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Switch Statement

• switch (expression)
• case (value)
• actions
• case (value)
• more actions
• default
• actions executed if none of above
• Here you can have many values for the expression.

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Switch Statement

• on (release)
• audioClip Math.floor(Math.random() 4)
• switch (audioClip)
• case 0
• trace ("BIFF!")
• case 1
• trace ("BAM!")
• case 2
• trace ("POW!")
• case 3
• trace ("BOOM!")
• default
• trace (Default message)
• Test this statement on a button.

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Switch Statement

• on (release)
• audioClip Math.floor(Math.random() 4)
• switch (audioClip)
• case 0
• trace ("BIFF!")
• break
• case 1
• trace ("BAM!")
• break
• case 2
• trace ("POW!")
• break
• case 3
• trace ("BOOM!")

Use break to jump out of cascade through the
switch statement.
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Lab Assignment

• Create a commented Flash movie that provides
  buttons for the user to
• Move an object left, right, up, down and to the
  center of the screen and have the object wrap
  when it reaches the edge of the screen
• Scale an object larger / smaller
• Rotate an object clockwise in 45 degree
  increments
• Name the movie buttonanimation.fla publish it
  and post the .htm and .swf to your UNIX account.