So I'm practicing creating a platformer game. I've got a movement system working, but when trying to add collision with platforms I have a problem.
What I did was add each platform to an array, and then check for collision between the player and each platform, since I just have a bunch of nameless instances of the platform symbol on my stage. The issue with this is that for my jumping code I use a boolean "onGround", which determines whether the player is 'on the ground' or not. And since my 'for each' loop runs through EVERY platform, even if the player is on a certain platform, there are other ones he won't be on and so it returns the boolean onGround as false.
This is a problem with my jumping code in general, I'm just wondering where I should go from here. If I need to change my jumping code, or change the collision, or what. Any ideas would be great. Here is my code :
package
{
import flash.display.MovieClip;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.display.DisplayObject;
public class Main extends MovieClip
{
var arrowUp:Boolean = false;
var arrowDown:Boolean = false;
var arrowLeft:Boolean = false;
var arrowRight:Boolean = false;
var arrowUpReleased:Boolean = true;
var arrowDownReleased:Boolean = true;
var arrowLeftReleased:Boolean = true;
var arrowRightReleased:Boolean = true;
var onGround:Boolean = undefined;
var isJumping:Boolean = undefined;
var vx:Number = 0;
var vy:Number = 0;
var acceleration:Number = 1;
var gravity:Number = 0.3;
var jumpForce:Number = 7;
var speedLimit:uint = 6;
var platformArray:Array = new Array();
var platformNumber:uint = 0;
var thePlatform:MovieClip;
public function Main()
{
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased);
stage.addEventListener(Event.ENTER_FRAME, update);
for (var i:uint = 0; i < numChildren; i++)
{
if(getChildAt(i) is Platform)
{
platformArray.push(getChildAt(i));
}
}
for each (var platform:DisplayObject in platformArray)
{
if (platform.hitTestPoint(player.x, player.y + 20, true))
{
vy = 0;
onGround = true;
}
}
}
function keyPressed(event:KeyboardEvent):void
{
if (event.keyCode == 37)
{
arrowLeft = true;
arrowLeftReleased = false;
}
if (event.keyCode == 38)
{
arrowUp = true;
arrowUpReleased = false;
isJumping = true;
}
if (event.keyCode == 39)
{
arrowRight = true;
arrowRightReleased = false;
}
if (event.keyCode == 40)
{
arrowDown = true;
arrowDownReleased = false;
}
}
function keyReleased(event:KeyboardEvent):void
{
if (event.keyCode == 37)
{
arrowLeft = false;
arrowLeftReleased = true;
}
if (event.keyCode == 38)
{
arrowUp = false;
arrowUpReleased = true;
isJumping = false;
}
if (event.keyCode == 39)
{
arrowRight = false;
arrowRightReleased = true;
}
if (event.keyCode == 40)
{
arrowDown = false;
arrowDownReleased = true;
}
}
function update (event:Event):void
{
//ACCELERATION
if (arrowLeft)
{
if (vx > 0)
{
vx = 0;
}
if ((Math.abs(vx)) < speedLimit)
{
vx -= acceleration/2;
player.x += vx;
}
else
{
player.x += vx;
}
}
if (arrowRight)
{
if (vx < 0)
{
vx = 0;
}
if (vx < speedLimit)
{
vx += acceleration/2;
player.x += vx;
}
else
{
player.x += vx;
}
}
if (arrowUp && onGround)
{
vy = -jumpForce;
}
//DECELERATION
if (arrowLeftReleased)
{
if (vx < 0)
{
vx += acceleration;
player.x += vx;
}
}
if (arrowRightReleased)
{
if (vx > 0)
{
vx -= acceleration;
player.x += vx;
}
}
//GRAVITY
player.y += vy;
if (!onGround)
{
vy += gravity;
}
if (onGround && !isJumping)
{
vy = 0;
}
if (vy > 0)
{
onGround = false;
}
else
{
onGround = true;
}
//COLLISION
for each (var platform:MovieClip in platformArray)
{
if (platform.hitTestPoint(player.x, player.y + 20, true))
{
vy = 0;
onGround = true;
}
else
{
onGround = false;
}
}
trace (onGround);
}
}
}
P.S. what happens at the moment with that code is that the player hits the platform and stops, but onGround remains false
1 Correct answer
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