Programming games

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Programming games

• Programmer vs player. Tweening
• Review, hints cannonball
• Preview video
• work session (cannonball)
• Homework Cannonball with ball in a parabolic arc
• Next project Video

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Programmer versus player

• Programmer (creator/developer) users Flash to
  create (build) an application.
• Player is the name I give to the end-user of our
  applications.
• Programmer uses the Flash environment to build an
  application, including coding, drawing, etc.

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Text fields

• Text fields are created by the programmer and
  given initial values.
• Static text fields do not change during runtime
• Dynamic text fields can be changed by code
  (written by the programmer) during run time.
• Input text fields can be changed by the player
  AND by code. Presumably, code (written by the
  programmer) reads/examines the input text fields
  changed by the player.

4
Animation

• Is created by displaying sequences of pictures so
  that our eyes see movement.
• Cel animation (aka frame by frame) is a sequence
  of distinct frames. The programmer creates the
  distinct frames.
• Computed animation is generated by code changing
  what is on the screen. This could be moving
  things around, changing shape, color, visibility,
  alpha, etc.

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Tweening

• Flash provides a quick (quicker) way of producing
  the sequence of frames for cel (frame by frame)
  animation.
• Motion tweening specifying a movie clip instance
  or a shape moving along a path
• Shape tweening specifying a first and last shape
• This is still called frame by frame animation.
  The computer helps out during creation time.

6
Common problems

• Not naming things correctly (consistently)
• You can use your own names, but most be
  consistent
• In Bouncing Ball NOT using a button Component.
  This is different from buttons in the Common
  Library
• In cannonball not putting stop() in the first
  and last frame of the target symbol.
• In cannonball, mainly, but also bouncing ball
  pay attention to the origin (cross-hairs)

7
Hitting walls

• Angle of incidence equals angle of reflection
• Because the walls are horizontal and vertical,
  this means the change is pretty simple
• Hitting horizontal wall causes the vertical
  component to change sign
• Hitting vertical wall causes the horizontal
  component to change sign

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Change walls?

• Need to use transformation
• Use .rotation to determine angle
• Construct matrix
• See me!

9
Overview cannonball

• 1 frame
• target symbol has several frames
• 3 layers for organization
• May use additional layers for graphical effects
• 5 symbols in Library
• ball movie clip
• ground movie clip
• cannon movie clip
• target movie clip
• fire button
• Instances of those 5 symbols on the Stage (all
  named)
• Two input text fields and two static text fields

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ActionScript

• Main movie, actions layer
• Global variables, includingTimer object,
• register listeners for Timer event and fire
  button event,
• Function for starting the cannon ball flight
• Function for Timer event that advances the
  cannonball
• Later add code to check for collisions
• target symbol initial design 1 frame
• Later design add frames and stop() in first
  frame and last frame

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Cannonball

• Phase 1 get arc working
• Phase 2 add checks, add frames to target
• Target crumbles
• Target movie clip has cel animation
• After hit, goes on to frame 2 and subsequent
  frames.

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Advice/Warnings

• Put all the material in the board layer of the
  first frame.
• Give everything an instance name.
• Add layer for the interface elements text field
  and buttons
• Input text fields need the INSTANCE name.
• Add layer for actions
• If you want target to sink into (behind) ground,
  you make make a new layer and move (cut and paste
  in place) ground instance to it.

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Advice

• The firecannon code positions the ball. If your
  cannon is different than mine, you may need to
  modify this part of the code.
• The hitTestPoint is done material in the target
  clip versus balls x and y position.
• Make sure this is in the center
• The check for reaching the ground is done in
  terms of the ground's origin
• Make sure this is on the ground!

15
CB issues

• You need 4 text boxes!! The static text field
  label with the word speed The input text field
  holding the speedThe static text field label
  with the word angle or degrees The input text
  field holding the desired angle in degrees
• NOTE the application starts with values in speed
  and anglein

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CB issues

• The default for Flash is to go frame to frame
  so.
• For the crumbling target you need to put stop()
  in the first frame and the last frame

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Video in Flash

• More than one way to incorporate video into Flash
  (e.g., bring in whole video that plays along with
  the frames)
• The way described here uses a FLVPlayback object
• Requires an import statement
• This allows shorthand names for built-in parts of
  ActionScript
• Requires statement adding to Display list
• Objects created in code (as opposed to put
  directly on the Stage) need to be added to the
  Display list to be shown.

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Videos

• Different types of videos (like different types
  of images)
• Flash video playback requires videos of type .flv
• Can use Adobe Flash Media Encoder to take one
  type of video and produce an flv

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Basic coding

• import fl.video.
• var flvFLVPlayback
• flv new FLVPlayback()
• flv.source "dickey2.flv"
• flv.x 10
• flv.y 10
• addChild(flv)

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Homework

• Cannonball phases. GET first phase working BEFORE
  GOING ON.
• Note testing the program means to test when the
  ball hits the target and when it does not hit the
  target. You also should include going all the way
  over the target.
• Video
• read tutorials
• acquire videos