Some mesh advice

Troubleshooting graphics
1

Hey guys. So I’m attempting to do an implementation of an algorithm called “Speed Rock” that I found on the intarwebs and I’m debating between doing 1 of 2 things for the final step to finalizing the rock shape.

Let me quickly run over the steps in speed rock to better explain myself.

  1. Create a somewhat random assortment of boxes that are laid out in a grid fashion
  2. Collapse those boxes towards a center point to make a lumpy “Minecraft-like” shape.
  3. Using ray casting cast points from the outside to the center of the shape to create a sort of “dumb down” shape.

Step 3 is where I’m having a bit of a debate going on (Step 1 and 2 work fabulously and I’m quite proud of how it works so far). The debate is basically should I:
A) Move vertices on a sphere shape. (Sort of vacuum packing the blocky shape)
B) Create a new shape from scratch where I plot my ray casting sources in the same points as a sphere.

I’ve tried A but ended up with a weird assortment of triangles so I’m either doing something silly or this is totally not the way to go.

Thoughts anyone?

Just in case option A seems reasonable to what I’m doing here’s the code responsible for that
[java]

private void vacuumPackShape() {
    Sphere saran = new Sphere(10, 10,boundingSize * 2);
    
    Geometry geom = new Geometry("Saran", saran);
    VertexBuffer verticesBuffer = geom.getMesh().getBuffer(VertexBuffer.Type.Position);
    
    for(int i = 0; i < verticesBuffer.getNumElements(); i++) {
        
        Vector3f tempVec = new Vector3f();
        
        tempVec.setX((Float)verticesBuffer.getElementComponent(i, 0));
        tempVec.setY((Float)verticesBuffer.getElementComponent(i, 1));
        tempVec.setZ((Float)verticesBuffer.getElementComponent(i, 2));

        CollisionResults results = new CollisionResults();
        //Cast a ray from the sphere vertice to the opposite sphere vertice.
        Ray ray = new Ray(tempVec, new Vector3f(-tempVec.x,-tempVec.y,-tempVec.z));
        //The cubes node is where I store the cubes.
        cubes.collideWith(ray, results);
        System.out.println("Collisions:" + results.size());
        Vector3f newVec = results.getClosestCollision().getContactPoint();
        
        verticesBuffer.setElementComponent(i, 0, newVec.x);
        verticesBuffer.setElementComponent(i, 1, newVec.y);
        verticesBuffer.setElementComponent(i, 2, newVec.z);
        
    }
    
    Mesh newMesh = new Mesh();
    newMesh.setBuffer(verticesBuffer);
    
    geom.setMesh(newMesh);
    geom.updateModelBound();
    
    Material mat = new Material(am, "Common/MatDefs/Misc/Unshaded.j3md");
    mat.setColor("Color", ColorRGBA.Orange);
    mat.getAdditionalRenderState().setWireframe(false);
    geom.setMaterial(mat);
    node.attachChild(geom);
}

[/java]

2

Hm have you verified that your rayhit position is actually in the mesh coordiante system? Eg scaling might be off.

Also you might want to make sure your sphere is larger than your boxstuff, else you might only hit the opposite side.

3
@Empire Phoenix said: Hm have you verified that your rayhit position is actually in the mesh coordiante system? Eg scaling might be off.

Also you might want to make sure your sphere is larger than your boxstuff, else you might only hit the opposite side.

I’ll have to check that about where the rays actually hit. I’ll try that tonight.

Ya. The sphere is larger than the boxes. Initially it wasn’t but I fixed it’s little red wagon. I’ll post a screen shot as well tonight to show what’s going on. Thanks!