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[Ben_Hurr]

Alright, I put in a method where you check every pixel on the way to the collision.
It works... but now if you move diagonally against the wall, the object clips 1 pixel over the walls corners. 



Hotdamn.

[Tycho Brahe]

If you're moving fast (more than a few pixels in one update), just subdivide the move into several steps.  Even pixel-sized steps if you want.

It might just be eaisest to create a shape linking the start position to the end position and then hit-test against that

eg, instead of this, where you hit-test in all of the black boxes (and the light grey one hits):

Code:

              
               ▓▓▓▓▓▓
▓▓▓ ---> ▓▓▓ ->▓▒▒▒▓▓-> ▓▓▓
▓▓▓      ▓▓▓   ▓▒▒▒▓▓   ▓▓▓
               ▓▓▓▓▓▓
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

and then resolving it...

Code:

                ▓▓▓▓▓▓
            ▒▒▒▓▓▓▓▓▓
            ▒▒▒▓▓▓▓▓▓
               ▓▓▓▓▓▓
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

you do this, where you test the light grey areas:

Code:

                ▓▓▓▓▓▓
▓▓▓░░░░░░░░░░░░▓▓▓▓▓▓░░░░░░▓▓▓
▓▓▓░░░░░░░░░░░░▓▓▓▓▓▓░░░░░░▓▓▓
               ▓▓▓▓▓▓
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

and then resolve it by figuring out the last position at which they did not overlap (shown here in medium grey):

Code:

                ▓▓▓▓▓▓
▓▓▓░░░░░░░░░▒▒▒▓▓▓▓▓▓░░░░░░▓▓▓
▓▓▓░░░░░░░░░▒▒▒▓▓▓▓▓▓░░░░░░▓▓▓
               ▓▓▓▓▓▓
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓

This way, you only do one larger ABBA (or box) test, instead of a number of smaller ones. Even if the player is moving diagonally it would just be a matter of doing a few line/line intersection tests instead of a box. It *should* be quicker, however I'm no expert on collision detection/resolution and I haven't tested it so I might be wrong.

[Ben_Hurr]

Update:
I already solved that motherfucking bug.   :handshakeR:

It turns out I was iterating one too many times in my contact loop.  So when I'd test along the y axis, the objects x position would be 1 off from where it should be, thus fouling the y-axis test.

[Epitaph64]

Another way to do quick testing, is to find the ratio between X and Y speed between start of frame, and projected end of frame (if there were no collisions). So, say that you are moving 3 times faster X than Y. Then you check the object moving to the left for the amount of times that the X is a multiple of Y, and if it's colliding, return true (for collision). After that do the same for Y. If Y is greater, i.e. the object is falling at a speed of 4 and moving to the left at a speed of 1, reverse the order that you check them in.