// Sphere to sphere collision detection #include using namespace std; class Vector3D { float v[3]; // x,y,z public: Vector3D() { v[0] = v[1] = v[2] = 0; } Vector3D(float x, float y, float z) { v[0]=x; v[1]=y; v[2]=z; } float X() { return v[0];} float Y() { return v[1];} float Z() { return v[2];} void SetX(float x) { v[0]=x;} void SetY(float y) { v[1]=y;} void SetZ(float z) { v[2]=z;} Vector3D operator-(const Vector3D& b) { Vector3D v; v.v[0] = this->v[0]-b.v[0]; v.v[1]= this->v[1]-b.v[1]; v.v[2]=this->v[2]-b.v[2]; return v; } }; class Sphere { Vector3D center; float radius; public : Sphere() { center.SetX(0); center.SetY(0); center.SetZ(0); radius = 0.0f; } Sphere(Vector3D& c, float r) { center = c; radius = r; } Vector3D Center(){return center;} float Radius(){ return radius;} }; int DotProduct(Vector3D &a, Vector3D &b) { return a.X()*b.X() + a.Y()*b.Y() + a.Z()*b.Z(); } int SphereSphereCollision(Sphere& s1, Sphere& s2) { // calculate squared distance between centers Vector3D d = s1.Center() - s2.Center(); float dist = DotProduct (d, d); float radiussum = s1.Radius() + s2.Radius(); // the spheres intersect if squared distance // is less or equal to sum of radii return (dist <= radiussum + radiussum); } int main() { float r1,r2; Vector3D c1, c2; float c1x,c1y,c1z,c2x,c2y,c2z; cout << "Enter radius of first sphere; "; cin >> r1; cout << endl; cout << "Enter radius of second sphere; "; cin >> r2; cout << endl; cout << "Enter center of first sphere; "; cout << endl; cin >> c1x >> c1y >> c1z; c1.SetX(c1x); c1.SetY(c1y); c1.SetZ(c1z); cout << "Enter center of second sphere; "; cout << endl; cin >> c2x >> c2y >> c2z; c2.SetX(c2x); c2.SetY(c2y); c2.SetZ(c2z); Sphere s1(c1, r1); Sphere s2(c2, r2); if(SphereSphereCollision(s1, s2)) cout << "Spheres collide!"; else cout << "Spheres don't collide!"; return 0; }

Sphere to sphere intersection test