World::DetectCollision
Defined in:
Detects a collision between world geometry and a swept sphere.
C4World.h
Prototype
bool DetectCollision(const Point3D& p1, const Point3D& p2, float radius, uint32 kind,
CollisionData *collisionData, int32 threadIndex = ThreadMgr::kMaxWorkerThreadCount) const;
Parameters
p1 |
The beginning of the line segment in world space. |
p2 |
The end of the line segment in world space. |
radius |
The radius of the sphere. This cannot be negative, but it can be zero. |
kind |
The collision kind. |
collisionData |
The returned collision data. |
threadIndex |
The index of the Thread Manager worker thread that is calling this function. |
Description
The points specified by the parameters p1
and p2
, combined with the radius specified by the radius
parameter, define a directed swept sphere. The DetectCollision
function detects the first collision between this swept sphere and all enabled Geometry
nodes possessing collision information. If a collision is detected, then the function returns true
; otherwise, it returns false
.The
kind
parameter can be used to invalidate certain types of collisions. When a candidate geometry is encountered in the collision detection process, its collision exclusion mask is logically ANDed with the value of the kind
parameter. A collision can only occur if the result of this operation is zero. The collision mask associated with a geometry can be set using the GeometryObject::SetCollisionExclusionMask
function. The collision kind can be a combination (through logical OR) of the following predefined values and application-defined values.
kCollisionRigidBody |
Any type of rigid body. |
kCollisionCharacter |
A rigid body that represents a character. |
kCollisionProjectile |
A rigid body that represents a projectile. |
kCollisionVehicle |
A rigid body that represents a vehicle. |
kCollisionCamera |
A type of camera. |
kCollisionSightPath |
When used in an exclusion mask, does not obstruct sight. |
kCollisionSoundPath |
When used in an exclusion mask, does not obstruct sound. |
kCollisionBaseKind |
First application-defined collision kind. |
kCollisionExcludeAll |
When used as a collision exclusion mask, this value prevents collisions with everything. |
CollisionData
structure pointed to by the collisionData
parameter is filled out with information about the collision. The param
field of this data structure represents the fraction of the distance that the sphere traveled from p1
to p2
before the collision occurred.The
threadIndex
parameter specifies the index of the Thread Manager worker thread that has called the DetectCollision
function. If the DetectCollision
function is called from the main thread, then this parameter should not be specified so that the default value is used. If the DetectCollision
function is called from a job, then the threadIndex
parameter should be set to the value returned by the Job::GetThreadIndex
function. The threadIndex
parameter must be set correctly in order for multithreaded collision detection to work properly.
IMPORTANT. If the
The DetectCollision
function is called from inside a Thread Manager worker thread, then the application code must ensure that the scene is not modified while the job is running.
DetectCollision
function works by intersecting a line segment with the Minkowski sum of a sphere and arbitrary polygon meshes. The algorithm is very precise and can determine when collisions occur with the expanded faces, edges, or vertices of the mesh referenced by a geometry node. If the value of the radius
parameter is 0.0, then the collision detection reduces to a ray intersection with faces only.
See Also