Forums » Help » What do x and y variables of res.collision.slope exactly mean?

I've been logging this values to see how they work, and I've seen that the variable that changes between two sloped tiles (with the same angle) that point to different directions in the x axis is y ,(I thought it would be x) and the variable that changes between two sloped tiles wich point to the same direction in the x axis but a different direction in the y axis is x, and not y. So i wanted to know, how do this variables work?

T.b.h. the whole collision and tracing stuff is one of the things that have grown quite messy. I hope to be able to clean this up for 2.0.

From the documentation:

{
    collision: { x: false, y: false, slope: false },
    pos: { x: 0, y: 0 }, // Resulting object position
    tile: { x: 0, y: 0 } // Tile for the collision
}

collision.x and collision.y will be set to true if there was a collision on either axis with a fully solid tile. So if an entity collides with a wall, collision.x will be true, for floor/ceiling collisions, collision.y will be true. Note that both, x and y may be true for the trace, when a fast moving object collides with a corner.


The collision.slope property is either false (if there was no slope collision) or an object with the properties x, y - the slope direction - and nx, ny - the slope normal.

Assume a tilesize of 8. For a slope that goes from the upper left corner to the lower right, x, y will be 8, 8. A slope from the lower right corner to the upper left, will have -8, -8.


tile.x and tile.y will hold the tile number in case of a collision with a fully solid tile. This is made more sense before slopes where introduced in 1.19, in case you had some custom tiles. Now, it&039;s either #0 (no collision) or 1 (fully solid tile).

I hope that helps a bit :)