internal void AddRTScene(RayTracer_552.RTCamera c, RayTracer_552.SceneDatabase rtScene)
        {
            UWB_Primitive prim;

            NewSceneDatabase();
            SceneResource <RTGeometry> allGeom = rtScene.GetAllGeom();

            for (int i = 0; i < allGeom.Count; i++)
            {
                RTGeometry g = (RTGeometry)allGeom.ResourceLookup(i);
                switch (g.GeomType())
                {
                case RTGeometry.RTGeometryType.Sphere:
                    RTSphere s = (RTSphere)g;
                    prim = CreateSphereMesh();
                    SetMeshMaterial(prim, rtScene.GetMaterial(s.GetMaterialIndex()));
                    float scale = s.Radius / 2f;
                    CreateNode(s.Center, scale, scale, scale, prim);
                    break;

                case RTGeometry.RTGeometryType.Rectangle:
                    RTRectangle r = (RTRectangle)g;
                    prim = CreateRectangle(r);
                    SetMeshMaterial(prim, rtScene.GetMaterial(r.GetMaterialIndex()));
                    UWB_SceneNode node = CreateNode(r.GetCenter(), r.GetUSize() / 2f, 1f, r.GetVSize() / 2f, prim);
                    // now rotate the y-vector of node to point towards r.Normal;
                    float dot = (float)Math.Abs(Vector3.Dot(Vector3.UnitY, r.GetNormal()));
                    if (dot < 0.9999f)
                    {
                        float   angle = (float)Math.Acos(dot);
                        Vector3 axis  = Vector3.Cross(Vector3.UnitY, r.GetNormal());
                        axis.Normalize();
                        Quaternion    q  = Quaternion.CreateFromAxisAngle(axis, angle);
                        UWB_XFormInfo xf = node.getXFormInfo();
                        xf.SetRotationQuat(q);
                        node.setXFormInfo(xf);
                    }
                    break;

                case RTGeometry.RTGeometryType.Triangle:
                    RTTriangle t = (RTTriangle)g;
                    Vector3[]  v = t.GetVertices();
                    prim = new UWB_PrimitiveTriangle(v[0], v[1], v[2]);
                    prim.EnableLighting(true);
                    prim.EnableTexturing(false);
                    SetMeshMaterial(prim, rtScene.GetMaterial(t.GetMaterialIndex()));
                    CreateNode(Vector3.Zero, 1f, 1f, 1f, prim);
                    break;
                }
            }
            AddCamera(c);
            AddLights(rtScene);

            // to show ray list
            mShownRayX  = mShownRayY = 0;
            mRaysToShow = new UWB_PrimitiveList();

            mDebugInfo = new UWB_SceneNode();
            mDebugInfo.setPrimitive(mRaysToShow);
            mDebugInfo.insertChildNode(mPixelsToShow.GetAllPixels());
            mDebugInfo.insertChildNode(mPixelInWorld.GetAllPixels());
        }