Bullet btBvhTriangleMeshShape Not Colliding

[kklouzal]

I'm attempting to create a btBvhTriangleMeshShape out of a large mesh in my application and use it as a Rigid Body. This Rigid Body will make up the 'ground plane' which is static and never moves. The problem is everything falls straight through like it's not even there. Here's the current source:

Code: Select all

    btTriangleMesh* tMesh = new btTriangleMesh();
    irr::scene::IMeshBuffer* MB = WorldNode1->getMesh()->getMeshBuffer(1);
 
    irr::video::S3DVertex* Vertices = (irr::video::S3DVertex*)MB->getVertices();
    irr::u16* Indices = MB->getIndices();
 
    for (irr::u32 i = 0; i < MB->getIndexCount(); i+=3)
    {
        irr::core::vector3df Tri1Pos = Vertices[Indices[i]].Pos;
        irr::core::vector3df Tri2Pos = Vertices[Indices[i+1]].Pos;
        irr::core::vector3df Tri3Pos = Vertices[Indices[i+2]].Pos;
 
        tMesh->addTriangle(btVector3(Tri1Pos.X, Tri1Pos.Y, Tri1Pos.Z), btVector3(Tri2Pos.X, Tri2Pos.Y, Tri2Pos.Z), btVector3(Tri3Pos.X, Tri3Pos.Y, Tri3Pos.Z));
    }
 
    btCollisionShape* groundShape = new btBvhTriangleMeshShape(tMesh, false);
    btDefaultMotionState* groundMotionState = new btDefaultMotionState(btTransform(btQuaternion(0, 0, 0, 1), btVector3(0, -1, 0)));
    PH->CreateRigidBody(0, groundMotionState, groundShape);

PH->CreateRigidBody() is just a helper function to quickly create rigid bodies, I know this function works properly since other objects use it and collide just fine.

Any insight into the issue here would be greatly appreciated. Thank you all very much for your time.

[hendu]

Enable debug drawing and see where it is.

[kklouzal]

Thank you very much hendu for the suggestion, I went ahead and got it setup and it appears to be in the correct location, here is a shot from the underneath of the mesh since you can't see the debug drawings from above it:

The red outline conforms correctly to the outside of the mesh, however I'm not sure what the green boxes are. The spherical rigid bodies have a red box around them so I'm assuming the red is the collision hull?

[kklouzal]

I hooked up an event receiver to spawn a rigid body sphere at the camera position and started flying around spamming spheres, it seems like they only collide with the green areas. So does that mean something's wrong with my mesh? Or something's wrong with the code I posted above to create the physics object out of the mesh?
Heres an above shot of the actual mesh for clarification:

[kklouzal]

I fixed it. The issue was that the mesh uses multiple materials so I need to also iterate through all the meshbufers, not just mesh buffer 0, whoops ^.^**