2 ball collision (2d plane)

[Spartaton]

I am not concerned with conservation of momentum, just the angle it is a game in space and all balls travel the same speed and are the same size anyways

Hey I'm currently making a game with MIT's app inventor (so I'll have some limited functionality) and I was wondering if anyone had a better idea to calculate the heading of the balls once they collide. Currently I'm finding the slope of the line between the coordinates of the ball and the raising the the -1 and multiplying by -1 to get the slope of the tangent line to the point of collision. Then depending on ball position (which one is higher, whether they are at the same y value) I run the angle of each ball (respect to the positive x axis) and the angle the tangent line creates through some equations to get the new heading for each ball (it currently boils down to an angle of incidence = angle of reflection off the tangent line which is hopefully realistic enough). So if anyone knows of a better way to do this, it would be much appreciated if you told me. I also will be adding in more balls (there will be 4-8 balls, haven't decided how many to have yet) so if there's a better way to handle it with more balls that might not be as efficient with only 2 please share.

 

The process:

y1 = ball1.y

y2 = ball2.y

x1 = ball1.x

x2 = ball2.x

m = y1 - y2 / x1 - x2

slope of tangent line = m ^ -1 * -1

angle of tangent line = atan2 (1, slope of tangent line)

 

And then 3 different equations all 5 lines long depending on the positioning of the ball ( ball1.y > ball2.y, ball1.y < ball2.y and ball1.y == ball2.y)

 

And then finally setting the new headings for BOTH the balls

[Enderman]

this is the correct way of doing it, i dont think there is anything shorter

but

i dont think you need 3 different equations for each case, the signs in front of the slope and the angle of the slope should be enough to determine the final angles of the balls

try it out and see, might need some tweaking and playing around with the - signs, but i think it can be done with a single equation

[Spartaton]

1 minute ago, Enderman said:

this is the correct way of doing it, i dont think there is anything shorter

but

i dont think you need 3 different equations for each case, the signs in front of the slope and the angle of the slope should be enough to determine the final angles of the balls

try it out and see, might need some tweaking and playing around with the - signs, but i think it can be done with a single equation

I figured as much. I plan on talking to my physics teacher about it on Monday since I have no education on the physics of balls.

[Enderman]

9 minutes ago, Spartaton said:

I figured as much. I plan on talking to my physics teacher about it on Monday since I have no education on the physics of balls.

are you just trying to do perfectly elastic collisions?

because if you are then your code is right