It is important that the absolute value of jt is used in the comparison, since the comparison is theoretically clamping raw magnitudes below some threshold. Another option would be to use a lookup table where the type of each body is used as an index into a 2D table. Really, any form of picking the friction coefficient will work this is just what I prefer.

An average of the two values would work perfectly fine to get rid of the use of square root. I actually saw someone else do this in their own physics engine, and I liked the result. In two dimensions, solving for this friction vector is a solvable problem, but in 3D the problem becomes much more complex.įriction is quite simple, and we can make use of our previous equation for j, except we will replace all instances of the normal n with a tangent vector t. This magnitude will modify the velocity of an object along the negative tangent vector of the collision, or in other words along the friction vector. Incorporating a friction response involves calculating another magnitude, referred to as jtangent or jT. This magnitude can be referred as jnormal or jN as it is used to modify velocity along the collision normal. Impulses, Again?Īs you should recall from the first article in this series, a particular value, j, represented the magnitude of an impulse required to separate two objects penetration during a collision. This is due to a lack of friction simulation. However, once the objects land on the solid platform, they just sort of all press away and drift off the edges of the screen. The interactions between the bodies are quite interesting, and the bouncing during collisions feels realistic.

3d demolition physics game