The answer to the bigger question is: not always. But let's assume that in our case, the answer is yes, and we can use a bounding box for everything. Let's al

The answer to the bigger question is: not always. But let's assume that in our case, the answer is yes, and we can use a bounding box for everything. Let's also assume that when a collision is detected between two objects, the results of that collision vary depending on what those objects are. How do we handle that? Well, we're back at the n² problem again. I once wrote a version of Asteroids in C++ in which every object had a particular bounding shape that was used for the detection. For the logic, I still had n² cases to determine the result of that collision. Looking back, I contend that it would have been cleaner to use the visitor pattern, since all the logic in my game was contained in various game objects except for the collision handling logic. [1] It's good to be skeptical of design patterns. I've worked at several companies where liberal application of patterns really mucked up the code base. But in some cases, they really can be the best solution -- when used conservatively and carefully. [1]: Looking back I also would have used an entity system rather than "classic" OOP, but that would not have solved the n² case dilemma.