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[Alex May]

It should be fairly easy to do in a physics/vector environment - shoot a ray in your current downward direction and change your downward direction to point in the opposite direction to the normal you receive from the collision system. For sharp or right-angled corners, it would make sense to shoot many rays along a set of angles between some +/- N degrees away from the downward direction and taking the average of the resultant normals.

Not that this helps the arbitrary tiles / sloped tiles problem...

[salade]

if you haven't found a solution I think I found one.

find the differences x-xprevious and y-yprevious and add them together. that value will be called SUM for the sake of not being confusing.

do two place_free()s, one at (x+SUM,y) one at (x, y+SUM). this should serve as a collision check like this





the exact orientation depends on the direction your going and what adding and subtracting you do at the place_free points. if you want to switch directions, make suse to multiply SUM by -1 in one of the place free() points. you could say something like SUM*the sign of(direction-91).

this should work, I think. I just thought it up off the top of my head, so it is not tested. the important idea though is the difference between x and xprevious, and the y equivalent, since one of them will always be zero if you restrict your movement to horizontal and vertical.

people have already suggested this method, but this is just a way to implement it.

it shouldn't work on slopes though, that's beyond me...

[Loren Schmidt]

Thanks for the ideas, folks. I was working on this a while ago your ideas are better than mine were.

[Robotacon]

This is the code I use for wall crawlers (slightly edited for clarity). I test straight ahead in the direction the crawler is moving first and then under the crawlers feet or it won't work for me.

Code:

if( (speedX < 0) && wallLeft() ) {
    speedX = 0;
    speedY = -crawlSpeed;
} else if( (speedY < 0) && wallAbove() ) {
    speedx = crawlSpeed;
    speedY = 0;
} else if( (speedX > 0) && wallRight() ) {
    speedX = 0;
    speedY = this.maxSpeed;
} else if( (speedY > 0) && wallBelow() ) {
    speedX = -crawlSpeed;
    speedY = 0;
} else if( (speedX < 0) && !wallBelow() ) {
    speedX = 0;
    speedY = crawlSpeed;
} else if( (speedY < 0) && !wallLeft() ) {
    speedX = -crawlSpeed;
    speedy = 0;
} else if( (speedX > 0) && !wallAbove() ) {
    speedX = 0;
    speedY = -crawlSpeed;
} else if( (speedY > 0) && !wallRight() ) {
    speedX = crawlSpeed;
    speedY = 0;
}

I also have code so that crawlers drop to the ground if they are in mid air (if a tile is blown away) and crawl up out of blocks they get caught in but if I understand correctly you're not interested in that.

[BMcC]

Did you get it working, Paul?  I'm curious to know which solution you chose.

If you want, I could make a BQ script for this that you could mess around with.  (Gotta do that at some point, anyway!)