自定义物理引擎中的AABB与循环冲突

Question

我已经学习了这个教程:https://gamedevelopment.tutsplus.com/tutorials/how-to-create-a-custom-2D-physics-engine-the-basics-and-impulse-resolution-gamedev-6331来创建一个用C#（他几乎所有的工作时间都是错误和不一致的伪C++)的二维物理引擎。但是，当尝试AABB vs Circle collison（下图）时，两个刚体只是粘在一起，缓慢地向一个方向移动。

如果有人能帮助我，我会非常感谢，因为我已经花了几天时间，仍然不知道是什么导致了错误。

如果有人需要我的代码提供更多信息，我很乐意提供。

public static bool AABBvsCircle(ref Collision result) {
        RigidBody AABB = result.a.Shape is AABB ? result.a : result.b;
        RigidBody CIRCLE = result.b.Shape is Circle ? result.b : result.a;

        Vector2 n = CIRCLE.Position - AABB.Position;

        Vector2 closest = n;

        float x_extent = ((AABB)AABB.Shape).HalfWidth;
        float y_extent = ((AABB)AABB.Shape).HalfHeight;

        closest.X = Clamp(-x_extent, x_extent, closest.X);
        closest.Y = Clamp(-y_extent, y_extent, closest.Y);


        bool inside = false;

        if (n == closest) {
            inside = true;

            if (Abs(n.X) > Abs(n.Y)) {
                // Clamp to closest extent
                if (closest.X > 0)
                    closest.X = x_extent;
                else
                    closest.X = -x_extent;
            }

            // y axis is shorter
            else {
                // Clamp to closest extent
                if (closest.Y > 0)
                    closest.Y = y_extent;
                else
                    closest.Y = -y_extent;
            }
        }

        Vector2 normal = n - closest;
        float d = normal.LengthSquared();
        float r = ((Circle)CIRCLE.Shape).Radius;

        // Early out of the radius is shorter than distance to closest point and
        // Circle not inside the AABB
        if (d > (r * r) && !inside)
            return false;

        // Avoided sqrt until we needed
        d = (float)Sqrt(d);

        if (inside) {
            result.normal = -normal / d;
            result.penetration = r - d;
        }
        else {
            result.normal = normal / d;
            result.penetration = r - d;
        }

        return true;
    }

在“碰撞”结构中编辑1碰撞解析方法

public void Resolve() {
        Vector2 rv = b.Velocity - a.Velocity;
        float velAlongNormal = Vector2.Dot(rv, normal);

        if (velAlongNormal > 0)
            return;

        float e = Min(a.Restitution, b.Restitution);

        float j = -(1 + e) * velAlongNormal;
        j /= a.InvertedMass + b.InvertedMass;

        Vector2 impulse = j * normal;
        a.Velocity -= a.InvertedMass * impulse;
        b.Velocity += b.InvertedMass * impulse;

        const float percent = 0.2f; // usually 20% to 80%
        const float slop = 0.01f; // usually 0.01 to 0.1
        Vector2 correction = Max(penetration - slop, 0.0f) / (a.InvertedMass + b.InvertedMass) * percent * normal;
        if (float.IsNaN(correction.X) || float.IsNaN(correction.Y))
            correction = Vector2.Zero;
        a.Position -= a.InvertedMass * correction;
        b.Position += b.InvertedMass * correction;
    }

Answer 1

在对代码逻辑进行任何详细检查之前,我发现了这个潜在的错误：

result.normal=-normal/d；

由于D被设置为Normal.LengthSquared而不是Normal.Length，因此应用的位置校正可能比预期的小（多）或大（多）。鉴于您的对象“粘在一起”，很可能是前者，即d>1。