void DrawSelectedObject()
{
if (_lineMaterial == null)
{
return;
}
NewBoxCollider box = _selectedObject.GetComponent <NewBoxCollider> ();
if (box != null)
{
DrawCube(box.origin.dots, 1f);
DrawCube(box.origin.dots, 1.0005f);
DrawCube(box.origin.dots, 1.0006f);
DrawCube(box.origin.dots, 1.0007f);
DrawCube(box.origin.dots, 1.0008f);
return;
}
NewSphereCollider sphere = _selectedObject.GetComponent <NewSphereCollider> ();
if (sphere != null)
{
DrawSphere(sphere.radius, sphere.transform.position);
return;
}
}
public bool SphereToSphere(NewSphereCollider sphereA, NewSphereCollider sphereB)
{
// reference https://developer.mozilla.org/en-US/docs/Games/Techniques/3D_collision_detection
float distance = Mathf.Sqrt(
(sphereA.transform.position.x - sphereB.transform.position.x) * (sphereA.transform.position.x - sphereB.transform.position.x) +
(sphereA.transform.position.y - sphereB.transform.position.y) * (sphereA.transform.position.y - sphereB.transform.position.y) +
(sphereA.transform.position.z - sphereB.transform.position.z) * (sphereA.transform.position.z - sphereB.transform.position.z));
return(distance < (sphereA.radius + sphereB.radius));
}
public CollisionData SphereToSphereManifold(NewSphereCollider sphereA, NewSphereCollider sphereB)
{
// reference: https://gamedevelopment.tutsplus.com/tutorials/how-to-create-a-custom-2d-physics-engine-the-basics-and-impulse-resolution--gamedev-6331
// Manifold Initialisation
CollisionData manifold = new CollisionData();
manifold.bodyA = sphereA.transform.gameObject.GetComponent <NewRigidBody>();
manifold.bodyB = sphereB.transform.gameObject.GetComponent <NewRigidBody>();
manifold.bodyAobj = sphereA.transform.gameObject;
manifold.bodyBobj = sphereB.transform.gameObject;
manifold.normal = Vector3.zero;
manifold.penetration = 0.0f;
// Exit if no collision
manifold.wasCollision = SphereToSphere(sphereA, sphereB);
if (manifold.wasCollision == false)
{
return(manifold);
}
Vector3 relativePosition = sphereB.transform.position - sphereA.transform.position;
float distance = Mathf.Sqrt(
(sphereA.transform.position.x - sphereB.transform.position.x) * (sphereA.transform.position.x - sphereB.transform.position.x) +
(sphereA.transform.position.y - sphereB.transform.position.y) * (sphereA.transform.position.y - sphereB.transform.position.y) +
(sphereA.transform.position.z - sphereB.transform.position.z) * (sphereA.transform.position.z - sphereB.transform.position.z));
// Ensure there is a distance to avoid / 0 error
manifold.contacts = new List <Vector3>();
if (distance != 0.0f)
{
manifold.penetration = (sphereA.radius + sphereB.radius) - distance;
manifold.normal = relativePosition / distance;
manifold.contacts.Add(sphereA.transform.position);
}
// Avoid / 0 error
else
{
manifold.penetration = sphereA.radius;
manifold.normal = new Vector3(0.0f, 1.0f, 0.0f); // Consistent value (randomly chosen)
manifold.contacts.Add(manifold.normal * sphereA.radius + sphereA.transform.position);
}
return(manifold);
}
public bool SphereToBox(NewSphereCollider sphere, NewBoxCollider box)
{
// reference https://developer.mozilla.org/en-US/docs/Games/Techniques/3D_collision_detection
// find the closest point on the box to the center of the sphere
Vector3 closestPoint = Vector3.zero;
closestPoint.x = Mathf.Max(box.minBounds.x, Mathf.Min(sphere.transform.position.x, box.maxBounds.x));
closestPoint.y = Mathf.Max(box.minBounds.y, Mathf.Min(sphere.transform.position.y, box.maxBounds.y));
closestPoint.z = Mathf.Max(box.minBounds.z, Mathf.Min(sphere.transform.position.z, box.maxBounds.z));
// distance between closest point and center of the sphere
float distance = Mathf.Sqrt(
(closestPoint.x - sphere.transform.position.x) * (closestPoint.x - sphere.transform.position.x) +
(closestPoint.y - sphere.transform.position.y) * (closestPoint.y - sphere.transform.position.y) +
(closestPoint.z - sphere.transform.position.z) * (closestPoint.z - sphere.transform.position.z));
return(distance < sphere.radius);
}
public CollisionData BoxToSphereManifold(NewBoxCollider box, NewSphereCollider sphere)
{
// reference: https://gamedevelopment.tutsplus.com/tutorials/how-to-create-a-custom-2d-physics-engine-the-basics-and-impulse-resolution--gamedev-6331
// (NOTE reference is in 2d, had to add 3D as well as my own manifold stuff)
// Initialise manifold
CollisionData manifold = new CollisionData();
manifold.bodyA = box.transform.gameObject.GetComponent <NewRigidBody> ();
manifold.bodyB = sphere.transform.gameObject.GetComponent <NewRigidBody> ();
manifold.bodyAobj = box.transform.gameObject;
manifold.bodyBobj = sphere.transform.gameObject;
manifold.normal = Vector3.zero;
manifold.penetration = 0.0f;
manifold.wasCollision = false;
Vector3 relativePosition = sphere.transform.position - box.transform.position;
// Closest point on A to center of B
Vector3 closestPoint = Vector3.zero;
closestPoint.x = Mathf.Max(box.minBounds.x, Mathf.Min(sphere.transform.position.x, box.maxBounds.x));
closestPoint.y = Mathf.Max(box.minBounds.y, Mathf.Min(sphere.transform.position.y, box.maxBounds.y));
closestPoint.z = Mathf.Max(box.minBounds.z, Mathf.Min(sphere.transform.position.z, box.maxBounds.z));
// If Circle is inside Box
bool inside = false;
if (relativePosition == closestPoint)
{
inside = true;
// Find closest axis
if (Mathf.Abs(relativePosition.x) > Mathf.Abs(relativePosition.y) && Mathf.Abs(relativePosition.x) > Mathf.Abs(relativePosition.z))
{
// Clamp to closest extent
if (closestPoint.x > 0.0f)
{
closestPoint.x = box.extents.x;
}
else
{
closestPoint.x = -box.extents.x;
}
}
// y-axis is shorter
else if (Mathf.Abs(relativePosition.y) > Mathf.Abs(relativePosition.z))
{
// Clamp to closest extent
if (closestPoint.y > 0.0f)
{
closestPoint.y = box.extents.y;
}
else
{
closestPoint.y = -box.extents.y;
}
}
// z-axis is shorter
else
{
// Clamp to closest extent
if (closestPoint.z > 0.0f)
{
closestPoint.z = box.extents.z;
}
else
{
closestPoint.z = -box.extents.z;
}
}
}
Vector3 normal = sphere.transform.position - closestPoint;
float distance = (closestPoint.x - sphere.transform.position.x) * (closestPoint.x - sphere.transform.position.x) +
(closestPoint.y - sphere.transform.position.y) * (closestPoint.y - sphere.transform.position.y) +
(closestPoint.z - sphere.transform.position.z) * (closestPoint.z - sphere.transform.position.z);
// If no collision then return
manifold.wasCollision = (Mathf.Sqrt(distance) < sphere.radius);
if (manifold.wasCollision == false)
{
return(manifold);
}
distance = Mathf.Sqrt(distance);
// Flip collision normal if inside
if (inside == true)
{
manifold.normal = Vector3.Normalize(-normal);
}
else
{
manifold.normal = Vector3.Normalize(normal);
}
manifold.penetration = sphere.radius - distance;
// Contact point
manifold.contacts = new List <Vector3> ();
manifold.contacts.Add(closestPoint);
return(manifold);
}
