Vector2.Angle questions and confusion.

Questions & Answers
1

I am curious exactly how this method works, Vector2.Angle.
I know it takes in 2 parameters, bother vector2 objects, but what does it do to calculate the angle?
I used this function in my camera rotation script, for android, and used the positions of two touches to rotate camera if it got bigger or smaller. I also had a debug string output to a guiText object in my scene and got odd results.

  1. When my fingers are at a 45 degree angle (diagonal and not horizontal / vertical) the angle was said to be zero. Why could this be? Could it be due to my main camera not being horizontal or vertical?

  2. When my fingers are close to each other, the angle decreases. I keep them horizontal, but if i pinch in, the angle decreases, and if i pinch out, the angle increases, why is this?

  3. How cam I accommodate for this odd effect and what does it mean?

  4. When i take the angle of two points, does it form a triangle between the two points, or does it tell the orientation (according to being vertical or horizontal) of these two points?

  5. when thinking in 3d space, what does vector2.angle tell you, if i split up rotations into up/down (one plane) and left/right (2nd plane)? I am curious because i wnat to make an object chase another and want to use angles to see if it is facing the object based on its, and target object’s position. (not using vector 3 as i don’t know how to interpret what that angle means in 3d space as i would assume it needs two components that display 2 angles)

Sorry if these questions are vague or i am asking too much, i figured it would fit under this topic as it helps in the understanding of how Vector2.Angle (and an idea of Vector3) works.

2

Vector2.Angle(v1, v2) assumes that v1 and v2 are vectors, not positions - think of them as arrows based on (0,0) and pointing to v1 and v2. In screen coordinates, if v1 is at the top-left and v2 is at bottom-right, Vector2.Angle(v1,v2) will return 90 degrees; if your fingers are in the same line from (0,0), it will return 0 degrees, because the 2 vectors will point the same direction (the length, which is the distance from screen origin, doesn’t interfere with the angle).

It would be better in this case to use Vector2.Distance(v1,v2), because Distance assumes that v1 and v2 are positions - it will accurately report a increasing value when the fingers are getting away from each other, and a decreasing value when they’re getting closer.