Cleaning Up the Jump<\/h3>\n

Now our hero is jumping. But there is a problem. Sometimes the jump just doesn’t happen and even when it does, it feels a bit funny.<\/p>\n

After some testing what I found out was that the listeners were sometimes being called in the wrong order. If I clicked fast it would trigger the up event before the down event and it would immediately wipe out the power. I fixed this by doing 3 things<\/p>\n

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1. waiting to register the up event until the down event was triggered<\/li>\n
2. removing the down and up event listener after each one was triggered<\/li>\n
3. reregistering the events as needed<\/li>\n<\/ol>\n

   See the highlighted\u00a0lines below:<\/p>\n

   var StateMain = {\r\n    preload: function() {\r\n        game.load.image(\"ground\", \"images\/ground.png\");\r\n        game.load.image(\"hero\", \"images\/hero.png\");\r\n        game.load.image(\"bar\", \"images\/powerbar.png\");\r\n        game.load.image(\"block\", \"images\/block.png\");\r\n    },\r\n    create: function() {\r\n        this.power = 0;\r\n        \/\/turn the background sky blue\r\n        game.stage.backgroundColor = \"#00ffff\";\r\n        \/\/add the ground\r\n        this.ground = game.add.sprite(0, game.height * .9, \"ground\");\r\n        \/\/add the hero in \r\n        this.hero = game.add.sprite(game.width * .2, this.ground.y - 25, \"hero\");\r\n        \/\/add the power bar just above the head of the hero\r\n        this.powerBar = game.add.sprite(this.hero.x + 25, this.hero.y - 25, \"bar\");\r\n        this.powerBar.width = 0;\r\n        \/\/start the physics engine\r\n        game.physics.startSystem(Phaser.Physics.ARCADE);\r\n        \/\/enable the hero for physics\r\n        game.physics.enable(this.hero, Phaser.Physics.ARCADE);\r\n        game.physics.enable(this.ground, Phaser.Physics.ARCADE);\r\n        \/\/game.physics.arcade.gravity.y = 100;\r\n        this.hero.body.gravity.y = 200;\r\n        this.hero.body.collideWorldBounds = true;\r\n        this.hero.body.bounce.set(0, .2);\r\n        this.ground.body.immovable = true;\r\n        \/\/set listeners\r\n        game.input.onDown.add(this.mouseDown, this);\r\n    },\r\n    mouseDown: function() {\r\n        game.input.onDown.remove(this.mouseDown, this);\r\n        this.timer = game.time.events.loop(Phaser.Timer.SECOND \/ 1000, this.increasePower, this);\r\n        game.input.onUp.add(this.mouseUp, this);\r\n    },\r\n    mouseUp: function() {\r\n        game.input.onUp.remove(this.mouseUp, this);\r\n        this.doJump();\r\n        game.time.events.remove(this.timer);\r\n        this.power = 0;\r\n        this.powerBar.width = 0;\r\n        game.input.onDown.add(this.mouseDown, this);\r\n    },\r\n    increasePower: function() {\r\n        this.power++;\r\n        this.powerBar.width = this.power;\r\n        if (this.power > 50) {\r\n            this.power = 50;\r\n        }\r\n    },\r\n    doJump: function() {\r\n        this.hero.body.velocity.y = -this.power * 12;\r\n    },\r\n    update: function() {\r\n        game.physics.arcade.collide(this.hero, this.ground);\r\n    }\r\n}<\/pre>\n\n\n