Terrain Holes

[Leadwerks]

Is it possible to modify terrain tile collision by modifying the m_attribute array of the newtonheightfieldcollision object? Is the m_attribute an array of bytes? What value should I use to disable collision on a single terrain tile?

[JernejL]

I guess, you could check if the contacts are in specific region of heightfield and remove the contacts in that case.

[Leadwerks]

I remember Julio saying there was some way to disable specific terrain tiles. I thought that was what the attribute field was for.

[Julio Jerez]

The attribute face ID is the same as the Face Id of the faces in a collision tree,
You get them in a material callback like this

Code: Select all

// say the the id for invesible face is
#define HOLE_INTERRAIN 10

void GenericContactProcess (const NewtonJoint* contactJoint, dFloat timestep, int threadIndex)
{
   int isHightField;
   NewtonBody* body;
   NewtonCollision* collision;
   NewtonCollisionInfoRecord info;

   isHightField = 1;
   body = NewtonJointGetBody0 (contactJoint);
   collision = NewtonBodyGetCollision(body);
   NewtonCollisionGetInfo(collision, &info);
   if (info.m_collisionType != SERIALIZE_ID_HEIGHTFIELD) {
      body = NewtonJointGetBody1 (contactJoint);
      collision = NewtonBodyGetCollision(body);
      NewtonCollisionGetInfo(collision, &info);
      isHightField  = (info.m_collisionType == SERIALIZE_ID_HEIGHTFIELD);
   }

   if (isHightField) {
      void* nextContact;
      for (void* contact = NewtonContactJointGetFirstContact (contactJoint); contact; contact = nextContact) {
         int faceID;
         NewtonMaterial* material;

         nextContact = NewtonContactJointGetNextContact (contactJoint, contact);

         material = NewtonContactGetMaterial (contact);
         faceID = NewtonMaterialGetContactFaceAttribute (material);
         if (faceID == HOLE_INTERRAIN) {
            NewtonContactJointRemoveContact (contactJoint, contact);
         }
      }
   }
}

I hope thsi is eassy.
you can also do teh same for collison tree and make face invsisible if you want

[Leadwerks]

Works great!