How to jump on a spring in a platform game
I am creating a platform game in which I have created springs that should make my hero fly upwards like a trampoline. The problem I am having is as follows:
1. When I am touching the spring the spring mc remains in the "down" position and does not return to the "up" position
2. After touching the spring my hero character does not propell into the air
3. When touching the spring I cannot "jump" when pressing the spacebar to jump
Here is a screenshot of my spring and hero. The hero character is standing in the middle of the spring. On top of the ledge above my character I have 2 movie clips of the states of the spring: an up and a down position. The spring I am touching has a timeline with 3 label states: up, down, done
public function gameLoop(event:Event)
{
// get time difference
if (lastTime == 0) lastTime = getTimer();
var timeDiff:int = getTimer() - lastTime;
lastTime += timeDiff;
// only perform tasks if in play mode
if (gameMode == "play")
{
moveCharacter(hero,timeDiff);
moveEnemies(timeDiff);
checkCollisions();
scrollWithHero();
createLift();
moveMyLift();
//moveMyLift02();
}
}
public function moveCharacter(char:Object, timeDiff:Number)
{
if (timeDiff < 1) return;
// assume the character is pulled down by gravity
var verticalChange:Number = char.dy*timeDiff + timeDiff*gravity;
if (verticalChange > 15.0) verticalChange = 15.0;
char.dy += timeDiff*gravity;
// react to changes from key presses
var horizontalChange = 0;
var newAnimState:String = "stand";
var newDirection:int = char.direction;
if (char.moveUp)
{
horizontalChange = 0;
newAnimState = "climb";
if (hero.mc.hitTestObject(ladderObjects))
{
//for (var i:int = 0; i < fixedObjects.length; i++)
//for (var xyz:int = 0; xyz < ladderObjects.height; xyz--)
//{
//hero.mc.y -= 1;
trace("Hungry");
verticalChange = 0;
//}
}
}
if (char.moveDown)
{
horizontalChange = 0;
newAnimState = "climb";
}
if (char.moveLeft)
{
// walk left
horizontalChange = -char.walkSpeed*timeDiff;
newAnimState = "walk";
newDirection = -1;
}
else if (char.moveRight)
{
// walk right
horizontalChange = char.walkSpeed*timeDiff;
newAnimState = "walk";
newDirection = 1;
}
if (char.jump)
{
// start jump
char.jump = false;
char.dy = -char.jumpSpeed;
verticalChange = -char.jumpSpeed;
newAnimState = "jump";
}
if (hero.springSpeed == true)
{
if (char.springSpeed)
{
// start jump
char.springSpeed = false;
char.dy = -char.springSpeed;
verticalChange = -char.springSpeed;
newAnimState = "doublejump";
}
}
// assume no wall hit, hanging in air
char.hitWallRight = false;
char.hitWallLeft = false;
char.inAir = true;
// hit ladder
char.hitLadderRight = false;
char.hitLadderLeft = false;
// find new vertical position
var newY:Number = char.mc.y + verticalChange;
// loop through all fixed objects to see if character has landed
for (var i:int = 0; i < fixedObjects.length; i++)
{
if ((char.mc.x+char.width/2 > fixedObjects.leftside) && (char.mc.x-char.width/2 < fixedObjects.rightside))
{
if ((char.mc.y <= fixedObjects.topside) && (newY > fixedObjects.topside))
{
newY = fixedObjects.topside;
char.dy = 0;
char.inAir = false;
break;
}
}
}
// find new horizontal position
var newX:Number = char.mc.x + horizontalChange;
// loop through all objects to see if character has bumped into a wall
for(i=0;i<fixedObjects.length;i++) {
if ((newY > fixedObjects.topside) && (newY-char.height < fixedObjects.bottomside)) {
if ((char.mc.x-char.width/2 >= fixedObjects.rightside) && (newX-char.width/2 <= fixedObjects.rightside)) {
newX = fixedObjects.rightside+char.width/2;
char.hitWallLeft = true;
break;
}
if ((char.mc.x+char.width/2 <= fixedObjects.leftside) && (newX+char.width/2 >= fixedObjects.leftside)) {
newX = fixedObjects.leftside-char.width/2;
char.hitWallRight = true;
break;
}
}
}
// loop through ladders to see if character has touched a ladder
for(i=0;i<ladderObjects.length;i++) {
if ((newY > ladderObjects.topside) && (newY-char.height < ladderObjects.bottomside)) {
if ((char.mc.x-char.width/2 >= ladderObjects.rightside) && (newX-char.width/2 <= ladderObjects.rightside)) {
newX = ladderObjects.rightside+char.width/2;
char.hitLadderLeft = true;
break;
}
if ((char.mc.x+char.width/2 <= ladderObjects.leftside) && (newX+char.width/2 >= ladderObjects.leftside)) {
newX = ladderObjects.leftside-char.width/2;
char.hitLadderRight = true;
break;
}
}
}
// set the position of the character
char.mc.x = newX;
char.mc.y = newY;
// set animation state
if (char.inAir)
{
newAnimState = "jump";
}
char.animstate = newAnimState;
// move along walk cycle
if (char.animstate == "walk")
{
char.animstep += timeDiff/60;
if (char.animstep > char.walkAnimation.length)
{
char.animstep = 0;
}
char.mc.gotoAndStop(char.walkAnimation[Math.floor(char.animstep)]);
}
// not walking, show standing or jump state
else
{
char.mc.gotoAndStop(char.animstate);
}
// change direction
if (newDirection != char.direction)
{
char.direction = newDirection;
char.mc.scaleX = char.direction;
}
}
public function spring()
{
trace("I sprung");
hero.springSpeed = true;
//hero.dy = -hero.springSpeed;
//this.verticalChange = -hero.springSpeed;
//newAnimState = "doublejump";
//SpringAction(parent).gotoAndPlay("down");
}
// player collides with objects - not enemies
public function getObject(objectNum:int)
{
// award points for treasure
if (otherObjects[objectNum] is Treasure)
{
//var pb:PointBurst = new PointBurst(gamelevel, 100, otherObjects[objectNum].x, otherObjects[objectNum].y);
gamelevel.removeChild(otherObjects[objectNum]);
otherObjects.splice(objectNum, 1);
addScore(200);
}
// got the key, add to inventory
else if (otherObjects[objectNum] is Key)
{
//pb = new PointBurst(gamelevel, "Got Key", otherObjects[objectNum].x, otherObjects[objectNum].y);
playerObjects.push("Key");
gamelevel.removeChild(otherObjects[objectNum]);
otherObjects.splice(objectNum, 1);
}
// hit the door, end level if hero has the key
else if (otherObjects[objectNum] is Door)
{
if (playerObjects.indexOf("Key") == -1) return;
if (otherObjects[objectNum].currentFrame == 1)
{
otherObjects[objectNum].gotoAndPlay("open");
levelComplete();
}
}
// got the chest, game won
else if (otherObjects[objectNum] is Chest)
{
otherObjects[objectNum].gotoAndStop("open");
gameComplete();
}
// touched spring
else if (otherObjects[objectNum] is SpringAction)
{
otherObjects[objectNum].gotoAndPlay("down");
//hero.y -= 5;
// start jump
spring();
}
}
Thank you,
Alex
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