Emanuele Feronato

italian geek and PROgrammer

Talking about Platform game game, Actionscript 2, Flash and Game development.

It’s time to introduce ladders.

Ladders are quite hard to do for one reason: there is a lot of ways of intending ladders.

Can the player jump when on a ladder?

Should a ladder act as a hole if the player walks on it?

These are only two of the many questions you may ask about ladders.

So I have to made some rules:

1) Player climbs the ladder up and down using UP and DOWN arrows

2) Player can jump when on a ladder

3) If the player is falling and encounters a ladder, he will keep falling until he presses UP or DOWN

4) Player can climb a ladder if at least one of its corners is in the ladder

This is the actionscript

tile_size = 20;
ground_acceleration = 1;
ground_friction = 0.8;
air_acceleration = 0.5;
air_friction = 0.7;
ice_acceleration = 0.15;
ice_friction = 0.95;
treadmill_speed = 2;
max_speed = 3;
xspeed = 0;
yspeed = 0;
falling = false;
gravity = 0.5;
jump_speed = 6;
climbing = false;
climb_speed = 0.8;
level = new Array();
level[0] = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1];
level[1] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1];
level[2] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 1, 0, 0, 0, 0, 1];
level[3] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 1];
level[4] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 1];
level[5] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 1];
level[6] = [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 1, 0, 0, 0, 0, 0, 1];
level[7] = [1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 1];
level[8] = [1, 1, 1, 1, 0, 0, 0, 0, 0, 5, 5, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 1];
level[9] = [1, 1, 1, 1, 3, 3, 3, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 4, 4, 4, 4, 1, 1];
player = [5, 1];
function create_level(l) {
	_root.createEmptyMovieClip("level_container", 1);
	level_height = l.length;
	level_width = l[0].length;
	for (y=0; ymax_speed) {
		xspeed = max_speed;
	}
	if (xspeed0) {
		if ((bottom_right != 0 and bottom_right != 6) or (bottom_left != 0 and bottom_left != 6)) {
			if (bottom_right != 5 and bottom_left != 5) {
				y_pos = bottom*tile_size-9;
				yspeed = 0;
				falling = false;
				jumping = false;
			} else {
				if (prev_bottom0) {
		if ((top_right != 0 and top_right != 5 and top_right != 6) or (bottom_right != 0 and bottom_right != 5 and bottom_right != 6)) {
			x_pos = right*tile_size-6;
			xspeed = 0;
		}
	}
	x_pos = Math.round(x_pos);
	y_pos = Math.round(y_pos);
	prev_bottom = bottom;
}
function get_edges() {
	// right edge
	right = Math.floor((x_pos+5)/tile_size);
	// left edge   
	left = Math.floor((x_pos-6)/tile_size);
	// bottom edge
	bottom = Math.floor((y_pos+8)/tile_size);
	// top edge
	top = Math.floor((y_pos-9)/tile_size);
	// adjacent tiles
	top_right = level[top][right];
	top_left = level[top][left];
	bottom_left = level[bottom][left];
	bottom_right = level[bottom][right];
}

and this is the result

Any game on the horizon? I am making one…

Download the source code and enjoy.