Vector 2d collision how to#
Vector 2d collision code#

By definition circles are perfectly uniform. These properties are all we need to perform collisions between two circles. To keep things lightweight, consider a class Circle with three properties: The most basic form of collision returns true or false to indicate if two circles are touching.

Vector 2d collision code#

This also assumes perfectly elastic collisions.Although FlatRedBall XNA provides a Circle class for collisions, you may be interested in writing your own custom circle collision code for customizable behavior. And, hey, I once derived Euler angles on my own, so sometimes my back-of-the-napkin math actually works out. This is just back-of-the-napkin math, but it seems to give the correct results. If both spheres are moving, repeat the process for the other sphere (though you could probably simplify that equation to get some more efficient math). You can probably simplify the math down from there, of course, but it's late and I don't feel like doing it :) If the other sphere is moving, do the same in reverse. Add the result to the destination sphere's energy, subtract it from the original sphere's energy, and divide each, individually, by mass to get the resulting velocity. What seems correct for 2d physics is that you take the velocity * mass (energy) of a sphere, and multiply that by the normalized vector to the other sphere. What I think you want to do is find the collision normal between two circles, yes? If so, one of the cool properties of spheres is that if you find the distance between the centers of them, you can normalize that to get the normal of the sphere. Typically, a normal is just a normalized (length 1) vector indicating a direction, typically the direction that a poly faces on a 3d object.

Vector2 CMVelocity = (basket.Mass*basket.Velocity + base.Mass*base.Velocity)/(basket.Mass + base.Mass) Ĭaveat: I'm not going to assume that this is completely correct. If you just want to be able to simulate these things, use the center-of-mass frame: A basic physics textbook will cover this in an early chapter. To understand these collisions you have to understand momentum (and if you want collisions that aren't perfectly elastic, like when beanbags collide, you also have to understand energy). Will they both bounce equally? No, the cannonball will continue, barely noticing the impact, but the golf ball will reverse direction and fly away faster than it came. How about a cannonball and a golf ball, both moving at the same speed but in opposite directions, colliding head-on. Does the red ball rebound and leave the blue ball where it was? No, the blue ball gets knocked away and the red ball loses most of its speed (all, in the perfect case). Imagine playing pool: a fast red ball hits a stationary blue ball dead center. As written, when the two balls collide, each bounces off as if it had hit a glass wall tangent to both spheres, and that's not realistic. (Note that you can save some cycles by setting basketNorm = -baseNorm.) Is that right? If that's not right then we'll have to change the body of the if statement. A level floor has a normal of (0,1), and a ball with velocity (4,-3) hits it and flies away with velocity (4,3). If I'm reading your code right, the second argument to Vector2.Reflect is a normal to a surface. Vector2 basketNorm = baseMid - basketMid īaseVelocity = Vector2.Reflect(baseVelocity, baseNorm) īasketVelocity = Vector2.Reflect(basketVelocity, basketNorm) īasketMid = new Vector2((basketballTex.Width / 2 + basketPos.X), (basketballTex.Height / 2 + basketPos.Y)) īaseMid = new Vector2((baseballTex.Width / 2 + basePos.X), (baseballTex.Height / 2 + basePos.Y)) įirst the reflection. if ((Vector2.Distance(baseMid, basketMid)) < baseRadius + basketRadius) I also have Position, and Velocity which is being added to position to create the movement. Here I'm using a basketball and a baseball, hence base and basket. Ultimately I'm wanting to use the Vector2.Reflect Method to get a bit more realistic physics out of this exercise.ĮDIT: Added some code trying out suggestion(with no avail), probably misunderstanding the suggestion. I've gotten as far as that I'm suppose to calculate the Normal of the Velocity(Directional Speed) of the object, but that's where my college algebra mind over-heats, any I'm working with to 2d Circles that I have the centerpoint, radius, velocity, and position.

Vector 2d collision how to#

I'm having trouble wrapping my mind around how to calculate the normal for a moving circle in a 2d space.