AS3 Platformer Slope Detection - actionscript-3

Question

i am in the process of making a platformer in AS3. However, one thing im struggling with is how to manage slope detection. Preferably id like something similar to that of games like fancy pants adventures, but id really prefer not to use an external thing such as Box2D or CDK, because both of which confuse me greatly, and id generally prefer just to not have one. All my attempts have had the problem that i can get it to work with some slopes but not all (e.g character manages up one slope, but falls through the other) then when i change it to suit the other, it doesnt suit the first one (e.g player manages the second slope, but bounces up and down crazily on the second...
So, any help would be greatly appreciated...
Thanks.
Code is as follows.
//var setup
var leftPressed: Boolean = false;
var rightPressed: Boolean = false;
var upPressed: Boolean = false;
var downPressed: Boolean = false;
var leftBumping: Boolean = false;
var rightBumping: Boolean = false;
var upBumping: Boolean = false;
var downBumping: Boolean = false;
var lowerleftBumping: Boolean = false;
var lowerrightBumping: Boolean = false;
var leftBumpPoint: Point = new Point(-30, -87);
var rightBumpPoint: Point = new Point(30, -87);
var lowerleftBumpPoint: Point = new Point(-32, -2);
var lowerrightBumpPoint: Point = new Point(32, -2);
var upBumpPoint: Point = new Point(0, -174);
var downBumpPoint: Point = new Point(0, 0);
var scrollX: Number = -4;
var scrollY: Number = -68;
var ySpeed: Number = 0;
var xSpeed: Number = 0;
var speedConstant: int = 5;
var maxSpeedConstant: Number = 30;
var frictionConstant: Number = 0.9;
var gravityConstant: Number = 2;
var jumpConstant: Number = -45;
//game
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
stage.addEventListener(Event.ENTER_FRAME, loop);
function keyDownHandler(e: KeyboardEvent): void {
if (e.keyCode == Keyboard.LEFT) {
leftPressed = true;
} else if (e.keyCode == Keyboard.RIGHT) {
rightPressed = true;
} else if (e.keyCode == Keyboard.UP) {
upPressed = true;
} else if (e.keyCode == Keyboard.DOWN) {
downPressed = true;
}
}
function keyUpHandler(e: KeyboardEvent): void {
if (e.keyCode == Keyboard.LEFT) {
leftPressed = false;
} else if (e.keyCode == Keyboard.RIGHT) {
rightPressed = false;
} else if (e.keyCode == Keyboard.UP) {
upPressed = false;
} else if (e.keyCode == Keyboard.DOWN) {
downPressed = false;
}
}
function loop(e: Event): void {
if (back.hitTestPoint(player.x + leftBumpPoint.x, player.y + leftBumpPoint.y, true)) {
trace("leftBumping");
leftBumping = true;
} else {
leftBumping = false;
}
if (back.hitTestPoint(player.x + rightBumpPoint.x, player.y + rightBumpPoint.y, true)) {
trace("rightBumping");
rightBumping = true;
} else {
rightBumping = false;
}
if (back.hitTestPoint(player.x + upBumpPoint.x, player.y + upBumpPoint.y, true)) {
trace("upBumping");
upBumping = true;
} else {
upBumping = false;
}
if (back.hitTestPoint(player.x + downBumpPoint.x, player.y + downBumpPoint.y, true)) {
trace("downBumping");
downBumping = true;
} else {
downBumping = false;
}
if (back.hitTestPoint(player.x + lowerleftBumpPoint.x, player.y + lowerleftBumpPoint.y, true)) {
trace("lowerrightBumping");
lowerleftBumping = true;
} else {
lowerleftBumping = false;
}
if (back.hitTestPoint(player.x + lowerrightBumpPoint.x, player.y + lowerrightBumpPoint.y, true)) {
trace("lowerrightBumping");
lowerrightBumping = true;
} else {
lowerrightBumping = false;
}
if (leftPressed) {
xSpeed -= speedConstant;
} else if (rightPressed) {
xSpeed += speedConstant;
}
if (leftBumping) {
if (xSpeed < 0) {
xSpeed *= -0.5;
}
}
if (rightBumping) {
if (xSpeed > 0) {
xSpeed *= -0.5;
}
}
if (upBumping) {
if (ySpeed < 0) {
ySpeed *= -0.5;
}
}
if (downBumping) {
if (ySpeed > 0) {
ySpeed = 0; //set the y speed to zero
}
if (upPressed) {
ySpeed = jumpConstant;
}
} else {
ySpeed += gravityConstant;
}
if (xSpeed > maxSpeedConstant) { //moving right
xSpeed = maxSpeedConstant;
} else if (xSpeed < (maxSpeedConstant * -1)) { //moving left
xSpeed = (maxSpeedConstant * -1);
}
xSpeed *= frictionConstant;
ySpeed *= frictionConstant;
if (Math.abs(xSpeed) < 0.5) {
xSpeed = 0;
}
scrollX -= xSpeed;
scrollY -= ySpeed;
back.x = scrollX;
back.y = scrollY;
if (scrollY < -770) {
scrollX = -4;
scrollY = -68;
ySpeed=0
xSpeed=0
}
}

Answer 1

If I was forced to not use the love of my life (Box2D) then I suppose I would play around with hitTestObject and do some math on the angle of any of my slopes to generate the rate at which they would move to start. This question is a bit broad and I think the community here is more for specific problems and not architecture brainstorming.