//This goes through each node and then draws the end node's verticies
//This function should be called by starting with the rood node.
public void DrawOctree(cOctree pNode, cFrustum g_Frustum)
{
//Make sure a valid node was passed in; otherwise go back to the last node
if (pNode == null)
{
return;
}
// Make sure its dimensions are within our frustum
if (!g_Frustum.CubeInFrustum(pNode.m_vCenter.x, pNode.m_vCenter.y, pNode.m_vCenter.z, pNode.m_Width / 2))
{
return;
}
//Check if this node is subdivided. If so, then we need to draw its nodes
if (pNode.SubDivided)
{
//Recurse to the bottom of these nodes and draw
//the end node’s vertices, Like creating the octree,
//we need to recurse through each of the 8 nodes.
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.TOP_LEFT_FRONT], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.TOP_LEFT_BACK], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.TOP_RIGHT_BACK], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.TOP_RIGHT_FRONT], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.BOTTOM_LEFT_FRONT], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.BOTTOM_LEFT_BACK], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.BOTTOM_RIGHT_BACK], g_Frustum);
DrawOctree(pNode.m_pOctreeNodes[(int)eOctreeNodes.BOTTOM_RIGHT_FRONT], g_Frustum);
}
else
{
//Make sure we have valid vertices assigned to this node
if (pNode.m_pVertices.Length == 0)
{
return;
}
// Store the vertices in a local pointer to keep code more clean
Vector3[] pVertices = pNode.m_pVertices;
// Go through all of the vertices (the number of triangles * 3)
for (int i = 0; i < pVertices.Length; i += 3)
{
Debug.DrawLine(pVertices[i], pVertices[i + 1]);
Debug.DrawLine(pVertices[i + 1], pVertices[i + 2]);
Debug.DrawLine(pVertices[i + 2], pVertices[i]);
}
}
}
//Cleans up the subdivided node creation process, so our code isn't Huge
private void CreateNewNode(Vector3[] pVertices, bool[] pList, int numberOfVerts, Vector3 vCenter, float width, int triangleCount, int nodeID)
{
//Check if the first node found some triangles in it, else, return
if (triangleCount <= 0)
{
return;
}
//Allocate memory for the triangles found in this node
Vector3[] pNodeVertices = new Vector3[triangleCount * 3];
//Create a counter to count the current index of the new node vertices
int index = 0;
//Go through all the vertices and assign the vertices to the node’s list
for (int i = 0; i < numberOfVerts; i++)
{
//If this current triangle is in the node, assign its vertices to it
if (pList[i / 3])
{
pNodeVertices[index] = pVertices[i];
index++;
}
}
//Allocate a new node for the octree
m_pOctreeNodes[nodeID] = new cOctree();
//Get the new node’s center point depending on the nodeID
//(nodeID: meaning, which of the 8 subdivided cubes).
Vector3 vNodeCenter = GetNewNodeCenter(vCenter, width, nodeID);
//Increase the current level of subdivision
g_CurrentSubdivision++;
//Recurse through this node and subdivide it if necessary
m_pOctreeNodes[nodeID].CreateNode(pNodeVertices, triangleCount * 3, vNodeCenter, width / 2);
m_pOctreeNodes[nodeID].g_CurrentSubdivision = g_CurrentSubdivision;
//Decrease the current level of subdivision
g_CurrentSubdivision--;
}
