问重力/速度和跳跃问题(AS3，平台)

EN

import flash.events.MouseEvent;
import flash.events.Event;


var gravity:Number = 2;
var velocity:Number = 1.1;
var jumpPower:Number = 0;
var isJumping:Boolean = false;

jump.addEventListener(MouseEvent.CLICK, doJump);
function doJump(e:MouseEvent):void {
    if(!isJumping){
        jumpPower = 30;
        isJumping = true;
    }
}


//Just one ENTER_FRAME handler is better, 
//then you have more control over the order in which code gets run
//I've combined your three into one and called it gameLoop
stage.addEventListener(Event.ENTER_FRAME, gameLoop);

function gameLoop(e:Event):void {
    //this is the same, I just combined your 2 if's into one.
    if(kurz.hitTestObject(player) || kurz2.hitTestObject(player)){
        hitPlatform = true;
    }                             

    //you should set the velocity before assigning it to the player
    if(hitPlatform == true){
        velocity = 0;
        gravity = 2; //you probably want to reset gravity to default too
        isJumping = false; //SET isJumping to false now that you've hit a platform!  <-------------
    }else{
        velocity = 1.1; //you need to reset velocity when not on a platform
    }


    //Now that we've determined the velocity and if we're jumping, let's move the player the appropriate amount

    if(isJumping){
        //Since we're currently jumping, use the jumpPower instead of gravity
        player.y -= jumpPower;
        jumpPower -= 2;
    }else{
        if(!hitPlatform){
            //Since we're NOT JUMPING, and not on a platform, use gravity.
            gravity *= velocity;    
            player.y += gravity;  
        }
    }
}