Calculation of closest points between objects gives us the distance between these objects. These calculations are one of the most powerful in collision detection algorithms in a sense that they can minimize calculations a lot. If the combined maximum movement of the objects is less than the distance between them, a collision will not occur and we can save us a lot of time detecting the impact.
There is typically no physics functionality in graphics engines like Irrlicht. If you are using graphics and physics engines instead of one like Unity or Unreal Engine then you will run into a problem called “Irrlicht physics”. Recall that Irrlicht is just a graphics engine. It renders object on the screen and that is all. In order for an object to be able to have physics properties you would need to integrate physics and graphics engines.
Computer physics is the art of simulating a world inside a computer. The world doesn’t have to be real or resemble anything like our own planet. In a simulation, you can “invent” anti-gravity and see what happens when everything repulses all other objects. There are also some technical limitations when determining what kind of simulation you want to simulate. If you want to simulate how galaxies interact with each other, there is no point in simulating every star and planet in every galaxy. And, simulating every atom in every star and planet is certainly not feasible. A simulation is in most cases a simplification of a real world problem.
As the sphere is being the simplest primitive there is, the test for Sphere and AABB intersection is easy. This solution works also for Sphere Cube intersection tests.
When you want to do real time computer physics, like what we see in games, you will have to break the world into understandable items. It’s like Caesar’s divide and conquer tactic. When you are playing in a complex scene, all what really goes on in the physics engine is broken into small, but many pieces. This enables further optimization down the line, which will be covered later, but for now this keeps the collision detection and collision response algorithms easy to understand.
What is AABB? An AABB is an axis aligned bounding box. AABB vs AABB is a box vs box or bounding box collision detection. It’s mainly used in broadphase physics detection.
In simple collision detection algorithm we have calculated whether the two spheres were colliding. More advanced calculations include finding the time of the collision as well as the direction of the spheres during the test.
To determine if two spheres are colliding, we take the sum of the radiuses and compare it with the length from the centers of the spheres. If the length is smaller than the sum of the radiuses, we have a collision.
