Make system expression angle(x1,y1,x2,y2) to return 0-360?

As angle system expression returns value 0 to 180 then -180 to 0 clockwise. How to make it return 0-360 instead ?

You can use conditionals, but the expression usually comes out fine math wise.

If you need 0-360 for purposes of comparisons, etc., it can be normalized from 0-360 using:

(Angle % 360 + 360) % 360

Thanks, that works! I don't know why it work...Can you give me the direction where to study "%" operation like that. My highschool math class does not have thing like that.

It shouldn't matter if you do your math right. All angular operations should be cyclical so it doesn't matter if it returns -180 to 180 or 0 to 360. (Unless you display the result to the user.)

I use angle to drive animation frame so i want full absolute 360 degree.

The % is the modulo operator. It gets the division remainder between two numbers.

For example: 375 % 360 = 15, 360 % 360 = 0, 90 % 360 = 90, etc.

Step 1: Angle % 360

Single angle could be negative or positive, the first modulo returns a remainder between -359 to +359 degrees.

Step 2: Add 360 degrees

Returns the positive quadrant equivalent: (ex: -90 degrees would be pointing upward, this returns 270 degrees)

Step 3: % 360

If original angle was positive, step 2 would have caused it to exceed 360 degrees, so take the modulo again.

More information: http://stackoverflow.com/questions/1351925/why-does-2-mod-4-2

Thank you very much ,now this modulo thing make sense to me.

Thats actually a little scary. Hope you don't use 360 frames.