Have multiway keep track of the number of keys pressed for each direction

[cwgorman]

So if W and UP_ARROW both correspond to the same direction, pressing both at the same time will have no effect, instead of doubling the speed. Resolves issue #793.

[kevinsimper]

Hey @cwgorman

You are right, that is not the intended behaviour. That should be fixed!

I looked at the code and have some comments:

You should avoid creating new variables since that will force the garbace collecter to work and we will want to avoid that.
https://github.com/craftyjs/Crafty/pull/794/files#diff-006f862972d60d6e4ffefc1397f44328R711
https://github.com/craftyjs/Crafty/pull/794/files#diff-006f862972d60d6e4ffefc1397f44328R725

Is type conversion also needed here? (Have not runned the code myself, so can not immediately tell)
'' + this._keyDirection[k]] and var dir = '' + this._keyDirection[e.key];

[cwgorman]

@kevinsimper I've made the changes you've requested. Sorry it took so long; I haven't had much time for personal work lately.

I am curious about the garbage collection though. Is it actually slower than performing the additional lookups? I assumed the JS engines in today's browsers would be smart enough to optimize that.

[Chaosed0]

I ran into this one over the last weekend. Patch looks good to my unexperienced eye - anyone else still looking at this?

[mucaho]

How will this code perform in the following hypothetical case:
Imagine a space shooter where Q will move the player 1 square left and 1 square up (direction of -90 - 45 == -135), and E will move the player 1 square right and 1 square up (direction of 0 - 45 == -45). Now if Q and E are pressed together, player should just move 1 square up.

Maybe we could split the activeDirections map into activeDirectionsLeft, activeDirectionsRight, activeDirectionsUp and activeDirectionsDown; then increase/decrease the activeDirection__ counters by partitioning the key direction on an incoming key event:

• (-180 < direction < -90 || 90 < direction < 180 ) => LEFT
• (-0 < direction < -90 || 0 < direction < 90) => RIGHT
• (-0 < direction < -180) => UP
• (0 < direction < 180) => DOWN

This would solve the space shooter example, but still isn't precise enough for non-symmetric keys, but I think even this is overkill.

[mucaho]

ty cwgorman the proposed changed was integrated alongside other improvements to Multiway in #876