Programming games Demonstrate cannonball Homework: (bouncing ball due today) Cannonball Phase 1 due next week. Complete cannonball due following week.

Text fields Static: does not change Dynamic: can be changed by code Requires an instance name Input: can be changed by code OR by the player

Event handling Setting up Flash to listen for an event and do something when it occurs. Examples: flipbtn.addEventListener (MouseEvent.CLICK,flip); rockbtn.addEventListener (MouseEvent.CLICK, function(ev) { computerturn("rock");} );

Event handling other mouse events mybtn.addEventListener (MouseEvent.MOUSE_DOWN,showpic);

Event example for timing mytimer.addEventListener (TimerEvent.TIMER,moveball); Note: you need to have var mytimer:Timer = new Timer(50); And also mytimer.start();

Event example for video cam.addEventListener (ActivityEvent.ACTIVITY,activityHandler); Note: this needed prior coding to set up cam cam = Camera.getCamera(); cam.setMotionLevel(75,3000); See tutorial, examples on my site

Event handling Requires creating something by moving to Stage and naming buttons or other instances OR By creating things (using new term) in code Registering the event listener objectname.addEventListener (name of event , function to be called)

General comments In ALL programming, 'things' need to be named in order to manipulate them. In Flash, this means For dynamic and input text fields, you need to put a name into the Var field in the Properties panel For movie clips (such as the ball for bouncing ball), you need to put a name into the instance field. Flash 8 & 9: give instance name and use .text property

Passing of time: JavaScript The passing of time was handled/signaled using the setInterval(code, interval_length) sets up repeated events setTimeout(code, timed_amount) sets up one event

Passing of time: Flash One way: use frames Default 12 frames/second Cel animation uses this. Bouncing ball used Timer object. Also use this for cannonball

Reflect on Bouncing ball Computed animation Timer object, TimerEvent.TIMER registered (using addEventListener) to moveball mytimer.addEventListener (TimerEvent.TIMER, moveball); moveball(ev) ... Moved ball in straight line

Bo the dog [Look at source file]. The movie clip symbol uses cel animation (aka frame by frame animation) to show movement of legs. first frame: Bo sitting. Later frame, starting with frame with label shows movement. This is like rock-paper-scissors! The movie clip instance on the Stage is moved around much like the bouncing ball: computed animation. Note: no walls. Bo goes off on top/bottom/either side and then reappears.

Cannonball Example of ballistics aka projectile motion Simulation of effects of gravity Make the vertical displacements change! Horizontal displacements remain the same No wind resistance Initial vertical and horizontal motion calculated from angle of cannon

Cannonball (Flash) Interface angle of cannon specified, (not separate horizontal and vertical velocities) Requires the code to use trig functions to 'resolve' the vectors. This means calculate vertical and horizontal components from the (initial) velocity out of the cannon. Possible outcomes Hit ground Hit target: target crumples: Achieved by cel animation in the movie clip symbol for the target

Cannonball: collisions Collisions must be detected by coding! There are no ball, ground, target. I use target.hitTestPoint, a method that checks if the point (x,y) occupies the same position as any material of the target There also is hitTestObject, which compares bounding boxes I use if (ball.y > ground.y) for the check for hitting (reaching…going beyond) the ground Be sure that the origin/registration point for the ground is on the ground, not way above it!

Crumbling Target Instance of movie clip defined/added to Library Frame 1 shows original target. Actions panel has stop(); When target is determined to be hit in the Actions panel of Scene 1: target.goToAndPlay(2); Target Last frame has stop();

Reflection Mixture of computed and cel (frame by frame) animation Computed animation similar to bouncing ball Cel animation (in target movie not main movie) similar to rock-paper-scissors

More on angles Your code will rotate the cannon movie instance to 'be' the angle specified. Your code determines the (initial) horizontal movement and the (initial) vertical movement. The code does not check for a bad angle, meaning one 90 degrees or more. Opportunity for improvement

Angles Standard definition of angles is 360 degrees to a circle. This is what the player is shown Initial setting is 45 degrees. Most computer packages use radians, not degrees. Radians are an intrinsic measure. Take the radius of the circle and lay it around the circumference.

Radians

Radians Wrap a radius length around the circle. This defines an angle

Conversion See tutorial for this code. Built-in Math methods for trig functions. If you 'know' R and angle A P = R * Math.sin(A) M = R * Math.cos(A) R P A M

Animation Timer object, set up similar to Bouncing Ball The moveball function (for the final phase of cannonball) makes checks for the ground and the target I stress similarities so you can make use of concepts in your own work.

Animation … done by re-positioning ball based on calculation done with ActionScript. NOT by making new drawings in each frame.

Graphics (material) Can be 'off stage' For example, cannonball is positioned at mouth of cannon when FIRE button is released.

Homework Bouncing ball due today Start of Cannonball due next week. Just get the ball going in an arc first. Then create crumbling target and put checking for hitting in the code. Complete cannonball due following week. NOTE: this division of the project is done to teach you to plan and do this with your own projects!