人物跳跃不回地平台游戏AS3

Question

我正在制作一个平台游戏，其中主角左右移动并跳跃，但是我的角色跳跃并且没有 return 到地面，而是停留在 stage.My 角色电影的顶部-剪辑符号称为 'naruto'，我的地面符号称为 'ground'。

这是我的代码：

import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
import flash.display.MovieClip;
import flash.events.Event;
import flash.display.Stage;

naruto.gotoAndStop("stance");
var rightPressed:Boolean = new Boolean(false);
var leftPressed:Boolean = new Boolean(false);
var upPressed:Boolean = new Boolean(false);
var downPressed:Boolean = new Boolean(false);
var narutoSpeed:Number = 10;
stage.addEventListener(KeyboardEvent.KEY_DOWN,keyDownHandler);
stage.addEventListener(KeyboardEvent.KEY_UP,keyUpHandler);
stage.addEventListener(Event.ENTER_FRAME,gameLoop);


function keyDownHandler(keyEvent:KeyboardEvent):void
{
    if (keyEvent.keyCode == Keyboard.RIGHT)
    {
    rightPressed = true;    
    }
    else if(keyEvent.keyCode == Keyboard.LEFT)
    {
    leftPressed = true;
    }
    else if(keyEvent.keyCode == Keyboard.UP)
    {
    upPressed = true;
    }else if(keyEvent.keyCode == Keyboard.DOWN)
    {
    downPressed = true;
    }

}
function keyUpHandler(keyEvent:KeyboardEvent):void
{
    if (keyEvent.keyCode == Keyboard.RIGHT)
    {
    rightPressed = false;
        naruto.gotoAndStop("standright")
    }
    else if(keyEvent.keyCode == Keyboard.LEFT)
    {
    leftPressed = false;
    naruto.gotoAndStop("standleft") 
    }
    else if(keyEvent.keyCode == Keyboard.UP)
    {
    upPressed = false;
    naruto.gotoAndStop("stance")    
    }else if(keyEvent.keyCode == Keyboard.DOWN)
    {
    downPressed = false;
    naruto.gotoAndStop("stance")    
    }

}

function gameLoop(loopEvent: Event): void {
    //If the right key is pressed, and the left key is NOT pressed
    if (rightPressed && !leftPressed) {
        naruto.x += narutoSpeed;
        naruto.gotoAndStop("right");
    }

    if(leftPressed && !rightPressed) {
        naruto.x -= narutoSpeed;
        naruto.gotoAndStop("left");

    }
var jumpHeight =0;
var defaultJumpSpeed = 20;
var jumpSpeed = 20;




if(upPressed && naruto.hitTestObject(ground))
{
    trace("HELLO!");
naruto.y -= jumpSpeed;
jumpSpeed-= 4;
}


if(upPressed)
{
    trace("HELLO!");
jumpHeight++;
naruto.y -= jumpSpeed;
if(jumpHeight>10)
jumpSpeed -= 4;
}


if(naruto.hitTestObject(ground))
{
    trace("HELLO!");
jumpHeight =0;
jumpSpeed = defaultJumpSpeed;
}
    }

这是我的作品 link：https://www.mediafire.com/?8d5opy49fuqmup5

问题是：

Answer 1

主要问题是，在您当前的代码中，玩家只能处于 3 个位置：

无论地面位置是什么
16（按下向上并且角色没有接触地面
12（按下向上，角色接触地面）

请查看原始代码旁边的代码注释以解释发生的情况：

//you have this var inside the game loop, so every loop it resets to 20
var jumpSpeed = 20;

//so here, if up is pressed and the character is touching the ground
//you initiate a jump
if(upPressed && naruto.hitTestObject(ground))
{
    trace("HELLO!");
    naruto.y -= jumpSpeed;
    jumpSpeed-= 4;  //since you reset jumpSpeed to 20 every loop, this value will always just be 16
}


if(upPressed)
{
    trace("HELLO!");
    jumpHeight++;

    //if naruto is touching the ground
    //you are subtracting jumpSpeed above and right here again. 
    //so now the y position is 12 if touching the ground (or 16 if not touching the ground)
    //since you reset jumpSpeed to 20 every loop, it always be one of those two values
    naruto.y -= jumpSpeed; 


    if(jumpHeight>10)
    jumpSpeed -= 4;  //this serves no purpose, as your not using the value again and it gets reset to 20 next time the game loop runs
}

//this hit test will succeed in addition to the first one above when your jump starts.
if(naruto.hitTestObject(ground))
{
    trace("HELLO!");
    jumpHeight =0;
    jumpSpeed = defaultJumpSpeed;
}

要纠正你的跳跃，你需要按照以下方式做一些事情：

//initialize these vars outside of the game-loop for efficient and proper scoping (so their values don't reset every frame)
var isJumping:Boolean = false; //a flag to know if a jump is in progress
var jumpSpeed:Number = 0; //the current velocity of the jump
var defaultJumpSpeed:Number = 20; //the initial force (speed) of a jump
var jumpGravity:Number = 2; //subtract this from the speed every frame to slow the jump over time and fall
var onGround:Boolean = false; //a helper var for efficiency

function gameLoop(loopEvent: Event): void {
    //If the right key is pressed, and the left key is NOT pressed
    if (rightPressed && !leftPressed) {
        naruto.x += narutoSpeed;
        naruto.gotoAndStop("right");
    }

    if (leftPressed && !rightPressed) {
        naruto.x -= narutoSpeed;
        naruto.gotoAndStop("left");

    }

    //only do the hit test once per frame for efficiency (store the result)
    onGround = naruto.hitTestObject(ground);

    if (upPressed && onGround) {
        trace("START JUMP");
        isJumping = true;
        jumpSpeed = defaultJumpSpeed; //set the initial jump velocity
    }

    if(isJumping){ //if jumping
        naruto.y -= jumpSpeed; //move the player based off the current jump velocity
        jumpSpeed -= jumpGravity; //slow the jump every frame (eventually causing it to be negative making the player fall)
    }   

    //touching the ground and the up key is not pressed
    //it's very important to put !upPressed so this doesn't run at the time as the initial jump above
    if (!upPressed && onGround) {
        //stop any jump motion
        jumpSpeed = 0;
        isJumping = false;

        //you probably also want to snap the player to the ground
        naruto.y = ground.y - naruto.height + 2; //the plus 2 ensures that the ground and the player touch so the hit test succeeds
    }
}

人物跳跃不回地平台游戏AS3

Character jumping but not returning to ground platform game AS3

actionscript-3

flash

animation

game-physics