AS3 Flash game creation tutorial – part 6: timing

In previous part we added some gameplay, now it’s time to add timing.

I recommend you to read Understanding AS3 Timer Class.

I used time for two reasons: first, I want the player to collect as much coins as he can before a certain amount of time (to be defined), second to give the player some king of invulnerability every time he respawns.

To time the game, I created the time.as class with this content:

package {
	import flash.display.Sprite;
	import flash.utils.Timer;
	import flash.events.TimerEvent;
	import flash.text.TextField;
	public class time extends Sprite {
		private var time_passed = new showtime;
		public function time(movieclip) {
			movieclip.addChild(time_passed);
			var time_count:Timer = new Timer(1000);
			time_count.addEventListener(TimerEvent.TIMER, show_time);
			time_count.start();
		}
		public function show_time(event:TimerEvent) {
			time_passed.timetext.text=String(event.target.currentCount);
		}
	}
}

At line 7 showtime is a movieclip with a dynamic text to show time passed.

This class is invoked in the main as3circle.as file at line 6 and line 24, this way:

package {
	import flash.display.Sprite;
	import flash.events.Event;
	public class as3circle extends Sprite {
		public var keyboard_input:keys;
		public var time_limit:time;
		public var circle_hero = new circle;
		public var your_score = new score;
		public var level_wall = new wall;
		public var rotating_bar = new bar;
		public var my_score = 0;
		public var number_of_coins = 4;
		public function as3circle() {
			for (var i=1; i<=number_of_coins; i++) {
				var ingame_coin = new coin;
				addChild(ingame_coin);
			}
			addChild(your_score);
			your_score.y= 250;
			your_score.alpha = 0.2;
			addChild(circle_hero);
			addChild(rotating_bar);
			keyboard_input = new keys(this);
			time_limit = new time(this);
			addChild(level_wall);
			stage.addEventListener(Event.ENTER_FRAME,on_enter_frame);
		}
		public function on_enter_frame(event:Event) {
			if (keyboard_input.is_left()) {
				circle_hero.apply_force(-1,0);
			}
			if (keyboard_input.is_right()) {
				circle_hero.apply_force(1,0);
			}
			if (keyboard_input.is_up()) {
				circle_hero.apply_force(0,-1);
			}
			if (keyboard_input.is_down()) {
				circle_hero.apply_force(0,1);
			}
		}
		public function add_score(points) {
			my_score += points;
			if (my_score<0) {
				my_score = 0;
			}
			your_score.updatescore(my_score);
		}
	}
}

As for the invulnerability, I set the hero's alpha to 0.5 when he respawns at line 40 of circle.as, and in the same file I add 0.01 to the alpha at every frame, this way:

package {
	import flash.display.Sprite;
	import flash.events.Event;
	public class circle extends Sprite {
		private var x_speed:Number;
		private var y_speed:Number;
		private var power:Number;
		private var friction:Number;
		private var gravity:Number;
		public function circle() {
			init();
			addEventListener(Event.ENTER_FRAME, movement);
		}
		private function movement(e:Event) {
			if (alpha<1) {
				alpha+=0.01;
			}
			x+=x_speed;
			y+=y_speed;
			rotation += x_speed;
			y_speed += gravity;
			x_speed *= friction;
			y_speed *= friction;
			if (x>500 || x<0 ||  y >500 || y<0) {
				init();
			}
		}
		public function apply_force(x_force,y_force) {
			x_speed += (x_force*power);
			y_speed += (y_force*power);
		}
		public function init() {
			gravity = 0.1;
			power = 0.66;
			friction = 0.99;
			x_speed = 0;
			y_speed = 0;
			x = 50;
			y = 50;
			alpha=0.5;
		}
	}
}

This should grant almost two seconds of invulnerability at every respawn.

Then, I disabled the collision check with the bar and the coins (but I left the check with walls) when hero's alpha is less than 1.

If you look at coin.as, you will find it at line 18:

package {
	import flash.display.Sprite;
	import flash.events.Event;
	public class coin extends Sprite {
		// variables used in this class
		private var dist_x:int;
		private var dist_y:int;
		private var distance:int;
		// main function
		public function coin() {
			// calling place_coin function.
			// this function randomly places the coin in the field
			place_coin();
			// checking for collisions at every frame
			addEventListener(Event.ENTER_FRAME, check_collisions);
		}
		private function check_collisions(e:Event) {
			if (as3circle(root).circle_hero.alpha ==1) {
				// determining the distance between the hero and the coin
				// notice how do I refer the hero
				dist_x = x - as3circle(root).circle_hero.x;
				dist_y = y - as3circle(root).circle_hero.y;
				distance = dist_x*dist_x+dist_y*dist_y;
				// 1809 = (hero radius + coin radius)^2
				// this way I don't have to perform a square root to distance
				if (distance < 1089) {
					// if the hero picks up a coin, then move it elsewhere, add one point to the score and speed up the bar
					as3circle(root).add_score(1);
					as3circle(root).rotating_bar.adjust_speed(0.2);
					place_coin();
				}
			}
		}
		private function place_coin() {
			x = Math.floor(Math.random()*400)+50;
			y = Math.floor(Math.random()*400)+50;
		}
	}
}

and the same concept is applied to the bar.

Here it is the result:

And this is the source code for you to download. Next step will cover ads and leaderboards integration.

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214 GAME PROTOTYPES EXPLAINED WITH SOURCE CODE
// 1+2=3
// 100 rounds
// 10000000
// 2 Cars
// 2048
// A Blocky Christmas
// A Jumping Block
// A Life of Logic
// Angry Birds
// Angry Birds Space
// Artillery
// Astro-PANIC!
// Avoider
// Back to Square One
// Ball Game
// Ball vs Ball
// Ball: Revamped
// Balloon Invasion
// BallPusher
// Ballz
// Bar Balance
// Bejeweled
// Biggification
// Block it
// Blockage
// Bloons
// Boids
// Bombuzal
// Boom Dots
// Bouncing Ball
// Bouncing Ball 2
// Bouncy Light
// BoxHead
// Breakout
// Bricks
// Bubble Chaos
// Bubbles 2
// Card Game
// Castle Ramble
// Chronotron
// Circle Chain
// Circle Path
// Circle Race
// Circular endless runner
// Cirplosion
// CLOCKS - The Game
// Color Hit
// Color Jump
// ColorFill
// Columns
// Concentration
// Crossy Road
// Crush the Castle
// Cube Jump
// CubesOut
// Dash N Blast
// Dashy Panda
// Deflection
// Diamond Digger Saga
// Don't touch the spikes
// Dots
// Down The Mountain
// Drag and Match
// Draw Game
// Drop Wizard
// DROP'd
// Dudeski
// Dungeon Raid
// Educational Game
// Elasticity
// Endless Runner
// Erase Box
// Eskiv
// Farm Heroes Saga
// Filler
// Flappy Bird
// Fling
// Flipping Legend
// Floaty Light
// Fuse Ballz
// GearTaker
// Gem Sweeper
// Globe
// Goat Rider
// Gold Miner
// Grindstone
// GuessNext
// Helicopter
// Hero Emblems
// Hero Slide
// Hexagonal Tiles
// HookPod
// Hop Hop Hop Underwater
// Horizontal Endless Runner
// Hundreds
// Hungry Hero
// Hurry it's Christmas
// InkTd
// Iromeku
// Jet Set Willy
// Jigsaw Game
// Knife Hit
// Knightfall
// Legends of Runeterra
// Lep's World
// Line Rider
// Lumines
// Magick
// MagOrMin
// Mass Attack
// Math Game
// Maze
// Meeblings
// Memdot
// Metro Siberia Underground
// Mike Dangers
// Mikey Hooks
// Nano War
// Nodes
// o:anquan
// One Button Game
// One Tap RPG
// Ononmin
// Pacco
// Perfect Square!
// Perfectionism
// Phyballs
// Pixel Purge
// PixelField
// Planet Revenge
// Plants Vs Zombies
// Platform
// Platform game
// Plus+Plus
// Pocket Snap
// Poker
// Pool
// Pop the Lock
// Pop to Save
// Poux
// Pudi
// Pumpkin Story
// Puppet Bird
// Pyramids of Ra
// qomp
// Quick Switch
// Racing
// Radical
// Rebuild Chile
// Renju
// Rise Above
// Risky Road
// Roguelike
// Roly Poly
// Run Around
// Rush Hour
// SameGame
// SamePhysics
// Save the Totem
// Security
// Serious Scramblers
// Shrink it
// Sling
// Slingy
// Snowflakes
// Sokoban
// Space Checkers
// Space is Key
// Spellfall
// Spinny Gun
// Splitter
// Spring Ninja
// Sproing
// Stabilize!
// Stack
// Stick Hero
// String Avoider
// Stringy
// Sudoku
// Super Mario Bros
// Surfingers
// Survival Horror
// Talesworth Adventure
// Tetris
// The Impossible Line
// The Moops - Combos of Joy
// The Next Arrow
// Threes
// Tic Tac Toe
// Timberman
// Tiny Wings
// Tipsy Tower
// Toony
// Totem Destroyer
// Tower Defense
// Trick Shot
// Tunnelball
// Turn
// Turnellio
// TwinSpin
// vvvvvv
// Warp Shift
// Way of an Idea
// Whack a Creep
// Wheel of Fortune
// Where's my Water
// Wish Upon a Star
// Word Game
// Wordle
// Worms
// Yanga
// Yeah Bunny
// Zhed
// zNumbers