如何进行正确的二维网格到圆碰撞检测

Question

I'm trying to do a mesh-to-circle collision system for my game. I've seen some examples where you iterate over all the verts of the mesh and check if they are inside the circle. But the problem is that sometimes the vertices are not inside the circle, but the lines that this vertices form are. In this cases, the collision check evaluates to false when it should evaluate to true. How can I make a good collision detection of this type? (in c/c++)

Answer 1

If you want you could calculate the distance from the line to the center of the circle. But I think it will be too costly. If the distance is lower than the radio you could have a collision. You will need to check if this part of the line is between the points. Distance line to point

Answer 2

实际上，一个快速的Google会让您知道这是堆栈上已经存在的一个问题的重复： 圆线段碰撞检测算法？

Answer 3

Just iterate over all the edges. And don't worry about the vertices: if a vertex is inside the circle, some edge is bound to cross it (unless the entire grid is inside the circle, which I'm guessing isn't likely).