I am having problems with my collision detection. basically when I hit a solid tile my character’s body is half way in the tile already. here is my code.
The properties wY and wX are my game world positioning. Not the stage positioning. dx and dy is the velocity the character is traveling. This first snippet of code is within a game loop. The focus point of my character is centered on the x axis
package com.objects
{
import flash.display.MovieClip;
import com.eapi.EngineApi;
import flash.events.Event;
/**
* ...
* @author Anthony Gordon
*/
public class Engine extends EngineApi
{
public var friction:Number = 0.93;
protected var Heros:Array;
public function Engine(w:Number = 540,h:Number = 360, tw:Number = 50, th:Number = 50)
{
super(w, h, tw, th);
Heros = new Array();
}
override protected function loop(e:Event):void
{
UpdateObjects();
Rules();
CheckHero();
UpDateMap();
}
public function AddHero(g:GameObject):void
{
Heros.push(g);
}
protected function Rules():void
{
//Everything Has friction
for (var i:Number = 0; i < gameObjects.length; i++)
{
var char:GameObject = GameObject(gameObjects[i]);
char.dx *= friction;
//char.dy *= friction;
//Below is the tile positioning of my character
var cgridx:Number = Math.floor(char.wX / tileW);
var cgridy:Number = Math.floor(char.wY/ tileH);
//This is the tile in front of the character
var nextx:Number = Math.floor((char.wX + char.dx) / tileW);
var nexty:Number = Math.floor((char.wY + char.dy) / tileH);
//We assume the character is in the air before we figure it to be false
char.onGround = false;
//I am about to remove the vars from cgrid below. Keep a look out for issues in the future
if (mapHolder[currentMap][nexty][cgridx] == 0 || mapHolder[currentMap][nexty][cgridx] == 2)
{
//If character is falling down
if (char.dy > 0)
{
char.wY = (nexty * tileH) - 1;
cgridy = Math.floor(char.wY / tileH);
char.dy = 0;
char.onGround = true;
}
else if (char.dy < 0)//If character is going up
{
char.wY = (nexty * tileH) + (tileH + 1);
cgridy = Math.floor(char.wY / tileH);
char.dy = 0;
}
}
//mapHolder is a array that holds an array of maps and their tile numbers
if (mapHolder[currentMap][cgridy][nextx] == 2)
{
if (char.dx > 0)//if character is going right
{
char.wX = ((nextx * tileW) - 1);
}
else if (char.dx < 0)// if character is going left
{
char.wX = (nextx * tileW) + (tileW + 1);
}
char.dx = 0;
}
//if character is not on ground then keep faling
if (char.onGround == false)
{
char.dy += .9;
if (char.dy > 30) char.dy = 5;
}
}
}
protected function CheckHero():void
{
var char:Hero = Heros[0];
char.x = char.wX - offsX;
char.y = char.wY - offsY;
if (char.wX < 0)
{
char.wX = 0;
char.dx = 0;
}
if (char.wY < 0)
{
char.wY = 0;
char.dy = 0;
}
offsX = char.wX - (vWidth/2);
offsY = char.wY - (vHeight/2);
if (offsX < 0)
{
offsX = 0;
}
if (offsY < 0)
{
offsY = 0;
}
//If screen hits the world END STOP!!!
if ((offsX + vWidth) > wWidth)
{
offsX = (wWidth - vWidth);
}
if ((offsY + vHeight) > wHeight)
{
offsY = (wHeight - vHeight);
}
/////
//If char hits the end, Stop!!
if (char.wX > wWidth)
{
char.wX = char.wX - wWidth;
char.wX = wWidth;
}
}
}
}
Here is my character class
package com.objects
{
import flash.display.MovieClip;
import flash.events.*;
/**
* ...
* @author Anthony Gordon
*/
[Embed(source='../../../bin/Assets.swf', symbol='Hero')]
public class Hero extends GameObject
{
private var aKeyPress:Array;
private var jumpDisabled:Boolean = false;
public function Hero()
{
wY = 150;
wX = 90;
speed = .5;
aKeyPress = new Array();
TheGame.sr.addEventListener(KeyboardEvent.KEY_DOWN, keyDownListener);
TheGame.sr..addEventListener(KeyboardEvent.KEY_UP,keyUpListener);
}
private function keyDownListener(e:KeyboardEvent):void {
//trace("down e.keyCode=" + e.keyCode);
aKeyPress[e.keyCode]=true;
}
private function keyUpListener(e:KeyboardEvent):void {
//trace("up e.keyCode=" + e.keyCode);
aKeyPress[e.keyCode]=false;
}
override public function UpdateObject():void
{
Controls();
updatePosition();
}
private function Controls():void
{
wX += dx;
wY += dy;
if (aKeyPress[38])//Key press up
;//vy -= speed;
else if (aKeyPress[40])//Key press down
;//dy += speed;
if (aKeyPress[37])//left
dx -= speed;
else if (aKeyPress[39])//Right
dx += speed;
if (aKeyPress[32]){//space
jump();
}
}//End Controls
private function jump():void
{
if (!jumpDisabled)
{
if (onGround)
{
dy = -15;
jumpDisabled = true;
}
}
else
{
jumpDisabled = false;
}
}
}
}
Well I fixed the issue. It isnt the greatest but its ten times better then before. here is what I did..
I changed…
To this…
My character center points is in the middle on both the y axis and x axis. so to do this i did the following
left and right are the tiles to the left and right of the Hero. for left what I did was I got the next tile to the right by doing this (left + 1). then I got its pixel position my multiplying tileW by it (left + 1) * (tileW). All my tiles focus points are top left. So in order for the character to be positioned to the right. I had to add another half of tile. Otherwise my hero’s center point would be between the left tile and the tile to the right (i.e. left+1). For the right was almost the same. but you get the picture…. I hope.