The standard method would be to do the separating axis test (do a google search on that). In short: Two objects don’t intersect if you can find a line that separates the two objects. e.g. the objects / all points of an object are on different sides of the line. The fun thing is, that … Read more
User @i_4_got points to this page with a very efficent solution in Python. I reproduce it here for convenience (since it would have made me happy to have it here): def ccw(A,B,C): return (C.y-A.y) * (B.x-A.x) > (B.y-A.y) * (C.x-A.x) # Return true if line segments AB and CD intersect def intersect(A,B,C,D): return ccw(A,C,D) != … Read more
Compute unit vectors from the angles and take the angle of their average.
Try this code which makes use of a cross product: public bool isLeft(Point a, Point b, Point c){ return ((b.X – a.X)*(c.Y – a.Y) – (b.Y – a.Y)*(c.X – a.X)) > 0; } Where a = line point 1; b = line point 2; c = point to check against. If the formula is equal … Read more
I know it’s a bit late in the game, but I remembered this question from when it was new and I had a similar dillemma, and I accidently found the “right” solution, if anyone is still looking for one: <path d=” M cx cy m -r, 0 a r,r 0 1,0 (r * 2),0 a … Read more
The Fibonacci sphere algorithm is great for this. It is fast and gives results that at a glance will easily fool the human eye. You can see an example done with processing which will show the result over time as points are added. Here’s another great interactive example made by @gman. And here’s a simple … Read more
First, compute the center point. Then sort the points using whatever sorting algorithm you like, but use special comparison routine to determine whether one point is less than the other. You can check whether one point (a) is to the left or to the right of the other (b) in relation to the center by … Read more
This gives a signed angle for any angles: a = targetA – sourceA a = (a + 180) % 360 – 180 Beware in many languages the modulo operation returns a value with the same sign as the dividend (like C, C++, C#, JavaScript, full list here). This requires a custom mod function like so: … Read more
Here’s a demo: http://jsfiddle.net/thirtydot/JJytE/1170/ CSS: .circleBase { border-radius: 50%; behavior: url(PIE.htc); /* remove if you don’t care about IE8 */ } .type1 { width: 100px; height: 100px; background: yellow; border: 3px solid red; } .type2 { width: 50px; height: 50px; background: #ccc; border: 3px solid #000; } .type3 { width: 500px; height: 500px; background: aqua; … Read more
Your error comes from this line initially: var direction1 = Math.atan2(ball1.velocitY, ball1.velocityX); You have ball1.velocitY (which is undefined) instead of ball1.velocityY. So Math.atan2 is giving you NaN, and that NaN value is propagating through all your calculations. This is not the source of your error, but there is something else that you might want to … Read more