Get angle between 2 points

Question

There's a player. While moving cursor Id like to get angle between player and cursor. My code for this is :

public void mouseMoved(MouseEvent ev) {
    float angle = (float) Math.toDegrees(Math.atan2(ev.getX() - player.getCenterX(),
            ev.getY() - player.getCenterY()));
    if (angle < 0) {
        angle += 360;
    }
    System.out.println(angle);
}

But it doesnt return correct values. How to modify it to return correct values?

Presumably, you're talking about the angle between two vectors, right? — , Mar 09 '13 at 22:18
One point is mouse cursor point and second is player point. From both I get coordinates — user2102972, Mar 09 '13 at 22:19
Then why are you using `atan2`? Just [take the `arccos` of the dot product divided by the product of the lengths.](http://en.wikipedia.org/wiki/Angle#Dot_product_and_generalisation) — , Mar 09 '13 at 22:20
From those two points, you get a line segment. It has a slope, but not an angle, because you need two intersecting lines/segments to have an angle between them. — cHao, Mar 09 '13 at 22:21

score 1 · Answer 1 · answered Mar 09 '13 at 22:21

1

This worked for me:

float angle = (float) Math.toDegrees(Math.atan2(-(ev.getX() - player.getCenterX()), ev.getY() - player.getCenterY()));
angle += 90;

answered Mar 09 '13 at 22:21

Wolfii

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Why use float and not double? Why not use arccos as Jack Maney suggests? – Hovercraft Full Of Eels Mar 09 '13 at 22:24
Because he used float and wrote my answer as Jack Maney posted his. Also I used similar code as i was making a game myself ^_^ – Wolfii Mar 09 '13 at 22:28

Get angle between 2 points

1 Answers1