Since gravity is a main feature and a core mechanics of my game, I wanted to write a post about it for quite some time.

The idea behind my gravity implimentation is surprisingly easy: find a collision point with a platform, get a normal in this point, use the tangent and the normal in this point as x and y axis. So, basically, multiply horizontal input by tangent vector, multiply vertical input (or gravity) by normal vector.

It isn't really that simple, but having circle collider for character and capsule colliders for platforms helps a lot.

For jumping I would just fix normal vector until I collided with a platform. I also smooth "horizontal" movement in air, and to get horizontal velocity in local space I project character velocity on the tangent vector using dot product.

But that's a jam, so of course there are a lot of hacks. I actually have two implimentations of gravity: first uses default Unity physics simulation, and it is used for player character only. But because in the last day of the jam I added an enemy, that needed it's own gravity separate from player, I have a second one, which is a hardcoded gravity specifically for this enemy.

To see all this stuff in action, try out my game, SkyCrawler: https://ldjam.com/events/ludum-dare/47/skycrawler