/*==LICENSE==*
CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011 Cyan Worlds, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
Additional permissions under GNU GPL version 3 section 7
If you modify this Program, or any covered work, by linking or
combining it with any of RAD Game Tools Bink SDK, Autodesk 3ds Max SDK,
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*==LICENSE==*/
#ifndef plOccTree_inc
#define plOccTree_inc
#include "hsTemplates.h"
#include "hsGeometry3.h"
class plBoundsHierarchy;
class plOccPlane
{
public:
hsVector3 fNormal;
hsScalar fDist;
};
class plOccPoly
{
public:
enum {
kEdgeClipped = 0x1
};
plOccPlane fPlane;
hsTArray fVerts;
hsTArray fEdgeFlags; // flag[i] => edge(fVerts[i], fVerts[(i+1)%n])
};
class plOccNode
{
protected:
enum {
kNone = 0x0,
kIsLeaf = 0x1
};
enum {
kAllIn = 0x0,
kAllOut = 0x1,
kSplit = 0x2
};
UInt32 fFlags;
plOccPlane fPolyPlane; // Plane of the poly we came from
plOccPlane fViewPlane; // Plane perp to view dir.
// For an interior node, ViewPlane is for the nearest (to view) point
// on the poly. A bound closer than that will not be occluded by this
// node or any nodes deeper in the tree.
// For a leaf it's the farthest point on the poly. A bound inside this
// plane OR the PolyPlane is occluded.
plOccNode* fInChild;
plOccNode* fOutChild;
};
class plOccTree
{
protected:
enum {
kNone = 0x0,
kNeedsBuild = 0x1
};
UInt8 fFlags;
// Temp pools for building our trees each frame.
hsTArray fPolyPool;
hsTArray fBasePolys;
// The BSP used to add our polys front to back. This BSP is constant.
plOccNode* fBSP;
// This current frame's view pos and occluder tree.
plOccNode* fRoot;
hsPoint3 fViewPos;
plOccNode* IAddPolyRecur(plOccNode* n, plOccPoly* poly);
void ITrimPoly(plOccPlane& plane, plOccPoly* polyIn, plOccPoly*& polyIn, plOccPoly*& polyOut);
plOccNode* IBuildOccTree();
public:
plOccTree() : fFlags(kNone), fBSP(nil), fRoot(nil) {}
~plOccTree() {}
// We'll take in the view position (for sorting and building).
// The view direction isn't necessary, but may be useful for
// selecting a subset of occluders (like don't bother with ones parallel to the view dir).
// What we really want is to pass in the viewport walls, or all the clip planes to initialize
// the occtree, then occluders out of view are automatically pruned, and the single test
// does the full view/portal/occluder test.
void SetView(const hsPoint3& pos, const hsVector3& dir);
// The algorithm is:
// if bnd is totally inside this node's plane
// recur bnd on inside child/leaf
// else if bnd is totaly outside this node's plane
// recur bnd on outside child
// else
// recur bnd's children on this node
//
// There's two ways to output the visibility info
// 1) Set a visible/invisible bit for each of the bnd leaves
// 2) output a list of visible bnds.
// The second is preferable, since leaves determined invisible by interior
// node tests never get traversed. But if the rendering pipeline has needs
// to traverse the drawable data in some other order (for depth or material
// sorting for example), then the list of visible bnds needs to be translated
// into the first option anyway.
//
// Notes on the vague algorithm:
// When recurring on the inside child, hitting a leaf checks against the source
// occluder poly, with the usual inside=hidden, outside=visible, split recurs
// the bnd's children on this leaf.
// Hitting a nil outside child == visible
// It's a double recursion, recurring first on the bnd hierarchy, and second on the occluder tree.
// Recursion stops when:
// 1) A bnd is totally in or totally out of a leaf of the occluder tree
// 2) A bnd is a leaf of the bnd hierarchy.
//
void TestHeirarchy(plBoundsHierarchy* bnd);
virtual void Read(hsStream* s, hsResMgr* mgr);
virtual void Write(hsStream* s, hsResMgr* mgr);
// Export only
void AddPoly(plOccPoly* poly);
void BuildBSP();
};
#endif // plOccTree_inc