AABBCollisionNode Class Reference

#include <OPC_OptimizedTree.h>

Related Functions
(Note that these are not member functions.)
	_BuildCollisionTree (AABBCollisionNode *linear, const udword box_id, udword &current_id, const AABBTreeNode *current_node)

Detailed Description

Definition at line 62 of file OPC_OptimizedTree.h.

Friends And Related Function Documentation

_BuildCollisionTree ( AABBCollisionNode *  linear, const udword  box_id, udword &  current_id, const AABBTreeNode *  current_node  )

related

Builds an implicit tree from a standard one. An implicit tree is a complete tree (2*N-1 nodes) whose negative box pointers and primitive pointers have been made implicit, hence packing 3 pointers in one.

Layout for implicit trees: Node:

• box
• data (32-bits value)

if data's LSB = 1 => remaining bits are a primitive pointer else remaining bits are a P-node pointer, and N = P + 1

Parameters

linear	[in] base address of destination nodes
box_id	[in] index of destination node
current_id	[in] current running index
current_node	[in] current node from input tree

Definition at line 101 of file OPC_OptimizedTree.cpp.

{
    // Current node from input tree is "current_node". Must be flattened into "linear[boxid]".

    // Store the AABB
    current_node->GetAABB()->GetCenter(linear[box_id].mAABB.mCenter);
    current_node->GetAABB()->GetExtents(linear[box_id].mAABB.mExtents);
    // Store remaining info
    if(current_node->IsLeaf())
    {
        // The input tree must be complete => i.e. one primitive/leaf
        OPASSERT(current_node->GetNbPrimitives()==1);
        // Get the primitive index from the input tree
        udword PrimitiveIndex = current_node->GetPrimitives()[0];
        // Setup box data as the primitive index, marked as leaf
        linear[box_id].mData = (PrimitiveIndex<<1)|1;
    }
    else
    {
        // To make the negative one implicit, we must store P and N in successive order
        udword PosID = current_id++;    // Get a new id for positive child
        udword NegID = current_id++;    // Get a new id for negative child
        // Setup box data as the forthcoming new P pointer
        linear[box_id].mData = (uintptr_t)&linear[PosID];
        // Make sure it's not marked as leaf
        OPASSERT(!(linear[box_id].mData&1));
        // Recurse with new IDs
        _BuildCollisionTree(linear, PosID, current_id, current_node->GetPos());
        _BuildCollisionTree(linear, NegID, current_id, current_node->GetNeg());
    }
}

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The documentation for this class was generated from the following files:

• src/cmd/collide2/OPC_OptimizedTree.h
• src/cmd/collide2/OPC_OptimizedTree.cpp