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By 'northWind'
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== Downloads ==
=== Collision Detector Only ===
After copying/merging in the requisite files from the collision detection package and adding all new files to your solution, the project should now be compiling cleanly. To get any use out of the collision detection, you will want to create a collision space, assign it to be the global collision space and implement the iRigidBody interface for your custom object classes. Let's take a look at this one step at a time:
<ol>
<li>Create a global collision space for all of your collision geometry. For the time being, the only collision space available is the simple one so let's do that:
<pre>
#include "iCollisionSpace.h"
#include "iSimpleCollisionSpace.h"
iCollisionSpace* collisionSpace = CreateSimpleCollisionSpace();
</pre>
</li>
<li>
Assign this collision space to be the global collision space for all collision geometries that will be created from this point on. This should be done during initialization and prior to collision geometry creation.<br/><br/>
From a design perspective, it should be possible for multiple collision spaces to coexist in the world but at the moment this is not implemented correctly so you will have to live with a single global collision space, unfortunately.
</li>
<li>
Implement the <code>iRigidBody</code> interface in some of your custom classes. A collision geometry requires a RigidBody instance to be passed in on creation (it can also be attached to a RigidBody at a later time); let's take a look at why this is so.
</li>
</ol>
==== CollisionGeometry and RigidBody ====
A collision geometry uses a RigidBody for location, rotation and velocity inforomation. When implementing the iRigidBody interface, it is crucial that <code>getRBDynamics()</code> return an up to date representation of the object's state in the world. At minimum, the following properties should be consistent with real-time attributes of the object:
<pre>
Vector position : Current position of COM
Vector com : Center of Mass offset.
PhysicsType physicsType : Type of physics applied to body, defaults to Falling (BUGGY, use PHYS_Falling and PHYS_Floating for now)
Matrix orientation : Matrix representing rotation in XYZ
</pre>
A couple of notes:
; PhysicsType physicsType : Always return PHYS_Falling or PHYS_Floating. The collision space will filter out collisions between PHYS_FixedInSpace objects to avoid unnecessary collision checks.
; Matrix orientation : Ensure that the rotation matrix has not been contaminated with any scale information, otherwise the collision tests may not return correct results. Oh, this might also be a good time to note that scaling is '''not supported''' by the physics simulator or the collision detector :)
Having said that, this should be enough to get your objects up and colliding. To detect all collisions at a given time in the world, call <code>populateContactList()</code> on the collision space. Retrieve the list of collisions by calling <code>getContactList()</code>; to find the number of contacts in the world, call <code>getNumContacts()</code>.
For more/misc information, see [[Team_Guardian_Physics#RigidBody |RigidBody Reference]] and the [[Team_Guardian_Physics#CollisionSpace |CollisionSpace Reference]].
== Framework Reference ==
=== Functions ===
; Vector getWorldCOM() const : '''REMOVED IN NEXT UPDATE''' Returns the world position of the COM with respect to this body.
; Vector getVelocityAtWorldPoint(const Vector& p) const : Given a point in worldspace, returns its speed taking into account velocity and angular velocity.
; Void setInverseInertiaTensor(const Matrix& i) : Sets the inverse inertia tensor of this body. Automatically sets the inertia tensor as well by inversing the incoming matrix. DOES NOT NEED TO BE CALLED AFTER CALLING setInertiaTensor()
; Matrix& getInverseInertiaTensor() : Returns the inertia tensor or inverse inertia tensor contained by this object.
; Void ApplyImpulse(const Vector& impulse, const Vector& pointOfApplication) : Applies a given impulse instantaneously onto this object at a given world point of application. Can be used to shoot or prod objects.
==== Functions Coming In Next Update ====
; void attachTo(RBDynamics* p) : Attaches this RBD to a given RBD. It is not required to call this function after calling PhysicsFrame's AttachTo(PhysicsFrame*) if the RBD resides within the RB of the PhysicsFrame.
; RBDynamics* attachedTo() const : Returns the RBD this RBD is attached to or NULL.
; RBDynamics* attachmentRoot() const : Returns the root of the attachment chain of this RBD.
; float getMass() const : Returns the mass of the RBD at the root of the attachment chain.
; Vector getWorldPosition() const : Returns the world-space position of this body's COM taking into account parent position/orientation.
; Matrix getWorldOrientation() const : Returns the world-space orientation of this body taking into account parent orientation.
== Other Topics Reference ==