AS3 Flash game creation tutorial – part 5: gameplay

Once introduced the score in AS3 Flash game creation tutorial – part 4: score, it’s time to create some gameplay.

The idea is to create a game like Collectabubble, just a bit more polished and with some more features.

The first thing to introduce is the rotating bar, a movieclip called bar with bar.as class.

This is the code of bar.as

package {
	import flash.display.Sprite;
	import flash.events.Event;
	public class bar extends Sprite {
		// variables used in this class
		private var point_x:int;
		private var point_y:int;
		// precision is the number of points I am going to calculate
		// on hero's circumference
		private var precision:int = 36;
		// calculating once for all 2*PI
		private var twopi: Number = Math.PI*2;
		// bar rotation speed
		public var rotspeed = 0.2;
		// main function
		public function bar() {
			// checking for collisions at every frame
			this.x = 250;
			this.y = 250;
			addEventListener(Event.ENTER_FRAME, check_collisions);
		}
		private function check_collisions(e:Event) {
			rotation += rotspeed;
			for (var i=0; i

As you can see, it's very similar to coin.as because it mainly does the same thing: checking for collision between the bar itself and the hero.

The only different thing the rotating bar does is... to rotate.

At line 14 you can find the variable that handles the rotation speed and at line 23 bar rotation is updated.

Once I detect a collision, I don't just reset hero (line 30) but I also subtract two points to the score (line 31) and slow down the bar (line 32).

How to slow down the bar? With adjust_speed function at lines 36-41.

If the bar slows down when the hero hits it, it must speed up when the hero picks up a coin.

That's why coin.as becomes

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) {
			// 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;
		}
	}
}

At line 28 I am increasing bar rotation speed at every coin collected.

Finally, it's useless to comment how the bar has been added to the main class, ascircle.as:

package {
	import flash.display.Sprite;
	import flash.events.Event;
	public class as3circle extends Sprite {
		public var keyboard_input:keys;
		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);
			addChild(circle_hero);
			addChild(rotating_bar);
			keyboard_input = new keys(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);
		}
	}
}

Other classes remain unchanged.

This is the result...

How much did you score? In next step I'll show you how to polish the gameplay with a timer.

Download the source code.

Get the most popular Phaser 3 book

Through 202 pages, 32 source code examples and an Android Studio project you will learn how to build cross platform HTML5 games and create a complete game along the way.

Get the book

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