/*
** Command & Conquer Generals(tm)
** Copyright 2025 Electronic Arts 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
** the Free Software Foundation, either version 3 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** 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 .
*/
/***********************************************************************************************
*** C O N F I D E N T I A L --- W E S T W O O D S T U D I O S ***
***********************************************************************************************
* *
* Project Name : WW3D *
* *
* $Archive:: /Commando/Code/Tools/max2w3d/aabtreebuilder.cpp $*
* *
* Original Author:: Greg Hjelstrom *
* *
* $Author:: Greg_h $*
* *
* $Modtime:: 5/24/00 8:41a $*
* *
* $Revision:: 4 $*
* *
*---------------------------------------------------------------------------------------------*
* Functions: *
* AABTreeBuilderClass::AABTreeBuilderClass -- Constructor *
* AABTreeBuilderClass::~AABTreeBuilderClass -- Destructor *
* AABTreeBuilderClass::Reset -- reset the builder, delete all arrays *
* AABTreeBuilderClass::Build_AABTree -- Build an AABTree for the given mesh. *
* AABTreeBuilderClass::Build_Tree -- recursivly builds the culling tree *
* AABTreeBuilderClass::Select_Splitting_Plane -- select a partition for the given polys *
* AABTreeBuilderClass::Compute_Plane_Score -- evaluate the suitability of a partition plane *
* AABTreeBuilderClass::Which_Side -- which side of a plane is the given poly *
* AABTreeBuilderClass::Split_Polys -- partition the polys with a plane *
* AABTreeBuilderClass::Compute_Bounding_Box -- compute bounding boxes for the cull nodes *
* AABTreeBuilderClass::Assign_Index -- assign an array index to each node *
* AABTreeBuilderClass::Node_Count -- Count the nodes in the tree *
* AABTreeBuilderClass::Poly_Count -- returns number of polys *
* AABTreeBuilderClass::Node_Count_Recursive -- internal implementation of Node_Count *
* AABTreeBuilderClass::Submit_Tree -- install nodes into an AABTreeClass *
* AABTreeBuilderClass::Submit_Tree_Recursive -- internal implementation of Submit_Tree *
* AABTreeBuilderClass::Update_Min -- ensure given vector is < min of the poly *
* AABTreeBuilderClass::Update_Max -- ensure given vector is > max of poly *
* AABTreeBuilderClass::Update_Min_Max -- ensure given vector is in min max of poly *
* AABTreeBuilderClass::Export -- Saves this AABTree into a W3D chunk *
* AABTreeBuilderClass::Build_W3D_AABTree_Recursive -- Build array of indices and W3dMeshAAB *
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
#include "aabtreebuilder.h"
#include "chunkio.h"
#include "w3d_file.h"
#include
#include
#include
#define WWASSERT assert // can't use WWASSERT because we use this module in the MAX plugin...
const float COINCIDENCE_EPSILON = 0.001f;
/***********************************************************************************************
* AABTreeBuilderClass::AABTreeBuilderClass -- Constructor *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
*=============================================================================================*/
AABTreeBuilderClass::AABTreeBuilderClass(void) :
Root(NULL),
CurPolyIndex(0),
PolyCount(0),
Polys(NULL),
VertCount(0),
Verts(NULL)
{
}
/***********************************************************************************************
* AABTreeBuilderClass::~AABTreeBuilderClass -- Destructor *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 5/19/2000 gth : Created. *
*=============================================================================================*/
AABTreeBuilderClass::~AABTreeBuilderClass(void)
{
Reset();
}
/***********************************************************************************************
* AABTreeBuilderClass::Reset -- reset the builder, delete all arrays *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 5/19/2000 gth : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Reset(void)
{
if (Root) {
delete Root; Root = NULL;
}
if (Verts != NULL) {
delete[] Verts;
Verts = NULL;
}
if (Polys != NULL) {
delete[] Polys;
Polys = NULL;
}
}
/***********************************************************************************************
* AABTreeBuilderClass::Build_AABTree -- Build an AABTree for the given mesh. *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Build_AABTree(int polycount,Vector3i * polys,int vertcount,Vector3 * verts)
{
WWASSERT(polycount > 0);
WWASSERT(vertcount > 0);
WWASSERT(polys != NULL);
WWASSERT(verts != NULL);
/*
** If we already have allocated data, release it
*/
Reset();
/*
** Copy the mesh data
*/
VertCount = vertcount;
PolyCount = polycount;
Verts = new Vector3[VertCount];
Polys = new Vector3i[PolyCount];
for (int vi=0; viPolyCount = polycount;
node->PolyIndices = polyindices;
return;
}
/*
** Try to find a suitable partitioning plane.
*/
SplitChoiceStruct sc;
sc = Select_Splitting_Plane(polycount,polyindices);
/*
** If the algorithm could not separate any polys, just install the polys
** in this node and terminate. TODO: explore how this happens.
*/
if (sc.FrontCount + sc.BackCount != polycount) {
node->PolyCount = polycount;
node->PolyIndices = polyindices;
return;
}
/*
** Decide whether to actually partition this node. If the partitioning
** will not gain us anything, just install the polys in this node and terminate
** the tree.
*/
#if 0
if (sc.Cost == MAX_COST) {
node->PolyCount = polycount;
node->PolyIndices = polyindices;
return;
}
#endif
/*
** Ok, split the polys
*/
SplitArraysStruct arrays;
Split_Polys(polycount,polyindices,sc,&arrays);
/*
** Free the memory in use by the input tile-list
*/
delete[] polyindices;
/*
** Build a front tree if necessary. Remember that the Build function
** deletes the poly array.
*/
if (arrays.FrontCount) {
WWASSERT(arrays.FrontPolys != NULL);
node->Front = new CullNodeStruct;
Build_Tree(node->Front,arrays.FrontCount,arrays.FrontPolys);
arrays.FrontPolys = NULL;
}
/*
** Build a back tree if necessary. Remember that the build function
** deletes the tile array.
*/
if (arrays.BackCount) {
WWASSERT(arrays.BackPolys != NULL);
node->Back = new CullNodeStruct;
Build_Tree(node->Back,arrays.BackCount,arrays.BackPolys);
arrays.BackPolys = NULL;
}
}
/***********************************************************************************************
* AABTreeBuilderClass::Select_Splitting_Plane -- select a partition for the given polys *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
AABTreeBuilderClass::SplitChoiceStruct
AABTreeBuilderClass::Select_Splitting_Plane(int polycount,int * polyindices)
{
WWASSERT(polyindices != NULL);
const int NUM_TRYS = 50;
SplitChoiceStruct best_plane_stats;
SplitChoiceStruct considered_plane_stats;
/*
** Try putting axis-aligned planes through some random vertices
*/
for (int trys = 0; trys < MIN(NUM_TRYS,polycount); trys++) {
AAPlaneClass plane;
/*
** Select a random poly and vertex index;
*/
int poly_index = polyindices[rand() % polycount];
int vert_index = rand() % 3;
const Vector3i * polyverts = Polys + poly_index;
const Vector3 * vert = Verts + (*polyverts)[vert_index];
/*
** Select a random plane
*/
switch(rand() % 3) {
case 0: plane.Set(AAPlaneClass::XNORMAL,vert->X); break;
case 1: plane.Set(AAPlaneClass::YNORMAL,vert->Y); break;
case 2: plane.Set(AAPlaneClass::ZNORMAL,vert->Z); break;
};
/*
** Get the score for this plane
*/
considered_plane_stats = Compute_Plane_Score(polycount,polyindices,plane);
if (considered_plane_stats.Cost < best_plane_stats.Cost) {
best_plane_stats = considered_plane_stats;
}
}
return best_plane_stats;
}
/***********************************************************************************************
* AABTreeBuilderClass::Compute_Plane_Score -- evaluate the suitability of a partition plane *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
AABTreeBuilderClass::SplitChoiceStruct
AABTreeBuilderClass::Compute_Plane_Score(int polycount,int * polyindices,const AAPlaneClass & plane)
{
/*
** The score of a splitting plane is based on the following factors:
** - the volumes of the resulting two children volumes,
** - the number of polys in each child volume
*/
SplitChoiceStruct sc;
sc.Plane = plane;
for (int i=0; i COINCIDENCE_EPSILON) {
mask |= POS;
}
if (delta < -COINCIDENCE_EPSILON) {
mask |= NEG;
}
mask |= ON;
}
/*
** Now evaluate the status of all of the verts to determine whether the
** triangle is in front, behind, on or overlapping the plane
*/
/*
** If all verts were ON the plane, the triangle is ON the plane
*/
if (mask == ON) {
return ON;
}
/*
** If all verts were POS or ON, the triangle is POS (IN_FRONT)
*/
if ((mask & ~(POS | ON)) == 0) {
return POS;
}
/*
** If all verts were NEG or ON, the triangle is NEG (BEHIND)
*/
if ((mask & ~(NEG | ON)) == 0) {
return NEG;
}
/*
** Otherwise, the triangle spans the plane
*/
return BOTH;
}
/***********************************************************************************************
* AABTreeBuilderClass::Split_Polys -- partition the polys with a plane *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Split_Polys
(
int polycount,
int * polyindices,
const SplitChoiceStruct & sc,
SplitArraysStruct * arrays
)
{
/*
** Note that this routine arrays of polygons. The caller is then responsible for keeping
** track of the memory this routine allocates.
*/
if (sc.FrontCount > 0) {
arrays->FrontPolys = new int[sc.FrontCount];
}
if (sc.BackCount > 0) {
arrays->BackPolys = new int[sc.BackCount];
}
arrays->FrontCount = 0;
arrays->BackCount = 0;
for (int i=0; iFrontPolys[arrays->FrontCount++] = polyindices[i];
break;
case BACK:
arrays->BackPolys[arrays->BackCount++] = polyindices[i];
break;
}
}
/*
** when we are all done, the counts should match.
*/
WWASSERT(arrays->FrontCount == sc.FrontCount);
WWASSERT(arrays->BackCount == sc.BackCount);
}
/***********************************************************************************************
* AABTreeBuilderClass::Compute_Bounding_Box -- compute bounding boxes for the cull nodes *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Compute_Bounding_Box(CullNodeStruct * node)
{
/*
** compute bounding volumes of the children
*/
if (node->Front) {
Compute_Bounding_Box(node->Front);
}
if (node->Back) {
Compute_Bounding_Box(node->Back);
}
/*
** compute bounding volume for the polys in this node
*/
node->Min.Set(100000.0f,100000.0f,100000.0f);
node->Max.Set(-100000.0f,-100000.0f,-100000.0f);
for (int poly_index = 0; poly_index < node->PolyCount; poly_index++) {
Update_Min_Max(node->PolyIndices[poly_index],node->Min,node->Max );
}
/*
** bound the polys in the front child node
*/
if (node->Front) {
if (node->Front->Min.X < node->Min.X) node->Min.X = node->Front->Min.X;
if (node->Front->Max.X > node->Max.X) node->Max.X = node->Front->Max.X;
if (node->Front->Min.Y < node->Min.Y) node->Min.Y = node->Front->Min.Y;
if (node->Front->Max.Y > node->Max.Y) node->Max.Y = node->Front->Max.Y;
if (node->Front->Min.Z < node->Min.Z) node->Min.Z = node->Front->Min.Z;
if (node->Front->Max.Z > node->Max.Z) node->Max.Z = node->Front->Max.Z;
}
/*
** bound the polys in the back child node
*/
if (node->Back) {
if (node->Back->Min.X < node->Min.X) node->Min.X = node->Back->Min.X;
if (node->Back->Max.X > node->Max.X) node->Max.X = node->Back->Max.X;
if (node->Back->Min.Y < node->Min.Y) node->Min.Y = node->Back->Min.Y;
if (node->Back->Max.Y > node->Max.Y) node->Max.Y = node->Back->Max.Y;
if (node->Back->Min.Z < node->Min.Z) node->Min.Z = node->Back->Min.Z;
if (node->Back->Max.Z > node->Max.Z) node->Max.Z = node->Back->Max.Z;
}
WWASSERT(node->Min.X != 100000.0f);
WWASSERT(node->Min.Y != 100000.0f);
WWASSERT(node->Min.Z != 100000.0f);
WWASSERT(node->Max.X != -100000.0f);
WWASSERT(node->Max.Y != -100000.0f);
WWASSERT(node->Max.Z != -100000.0f);
}
/***********************************************************************************************
* AABTreeBuilderClass::Assign_Index -- assign an array index to each node *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
int AABTreeBuilderClass::Assign_Index(CullNodeStruct * node,int index)
{
/*
** This function is used to assign a sequential index to
** each node in the tree. The AABTree stores its nodes in
** an array so this index is used to determine which slot
** in the array to put each node into.
*/
WWASSERT(node);
node->Index = index;
index++;
if (node->Front) {
index = Assign_Index(node->Front,index);
}
if (node->Back) {
index = Assign_Index(node->Back,index);
}
return index;
}
/***********************************************************************************************
* AABTreeBuilderClass::Node_Count -- Count the nodes in the tree *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
int AABTreeBuilderClass::Node_Count(void)
{
if (Root) {
return Node_Count_Recursive(Root,0);
} else {
return 0;
}
}
/***********************************************************************************************
* AABTreeBuilderClass::Poly_Count -- returns number of polys *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 10/23/98 GTH : Created. *
*=============================================================================================*/
int AABTreeBuilderClass::Poly_Count(void)
{
return PolyCount;
}
/***********************************************************************************************
* AABTreeBuilderClass::Node_Count_Recursive -- internal implementation of Node_Count *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/19/98 GTH : Created. *
*=============================================================================================*/
int AABTreeBuilderClass::Node_Count_Recursive(CullNodeStruct * node,int curcount)
{
curcount++;
if (node->Front) {
curcount = Node_Count_Recursive(node->Front,curcount);
}
if (node->Back) {
curcount = Node_Count_Recursive(node->Back,curcount);
}
return curcount;
}
/***********************************************************************************************
* AABTreeBuilderClass::Update_Min -- ensure given vector is < min of the poly *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/22/98 GTH : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Update_Min(int poly_index,Vector3 & min)
{
for (int vert_index = 0; vert_index < 3; vert_index++) {
const Vector3i * polyverts = Polys + poly_index;
const Vector3 * point = Verts + (*polyverts)[vert_index];
if (point->X < min.X) min.X = point->X;
if (point->Y < min.Y) min.Y = point->Y;
if (point->Z < min.Z) min.Z = point->Z;
}
}
/***********************************************************************************************
* AABTreeBuilderClass::Update_Max -- ensure given vector is > max of poly *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 6/22/98 GTH : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Update_Max(int poly_index,Vector3 & max)
{
for (int vert_index = 0; vert_index < 3; vert_index++) {
const Vector3i * polyverts = Polys + poly_index;
const Vector3 * point = Verts + (*polyverts)[vert_index];
if (point->X > max.X) max.X = point->X;
if (point->Y > max.Y) max.Y = point->Y;
if (point->Z > max.Z) max.Z = point->Z;
}
}
/***********************************************************************************************
* AABTreeBuilderClass::Update_Min_Max -- ensure given vector is in min max of poly *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 9/24/98 BMG : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Update_Min_Max(int poly_index, Vector3 & min, Vector3 & max)
{
for (int vert_index = 0; vert_index < 3; vert_index++) {
const Vector3i * polyverts = Polys + poly_index;
const Vector3 * point = Verts + (*polyverts)[vert_index];
if (point->X < min.X) min.X = point->X;
if (point->Y < min.Y) min.Y = point->Y;
if (point->Z < min.Z) min.Z = point->Z;
if (point->X > max.X) max.X = point->X;
if (point->Y > max.Y) max.Y = point->Y;
if (point->Z > max.Z) max.Z = point->Z;
}
}
/***********************************************************************************************
* AABTreeBuilderClass::Export -- Saves this AABTree into a W3D chunk *
* *
* This function will export the AABTree into a W3D chunk so that it can be loaded by its *
* sister class "AABTreeClass" in the WW3D library. *
* *
* INPUT: *
* *
* OUTPUT: *
* *
* WARNINGS: *
* *
* HISTORY: *
* 5/22/2000 gth : Created. *
*=============================================================================================*/
void AABTreeBuilderClass::Export(ChunkSaveClass & csave)
{
csave.Begin_Chunk(W3D_CHUNK_AABTREE);
/*
** Pack the tree into an array of W3dMeshAABTreeNode's and polygon indices
*/
W3dMeshAABTreeNode * nodes = new W3dMeshAABTreeNode[Node_Count()];
uint32 * poly_indices = new uint32[Poly_Count()];
int cur_node = 0;
int cur_poly = 0;
Build_W3D_AABTree_Recursive(Root,nodes,poly_indices,cur_node,cur_poly);
/*
** Write out the header
*/
csave.Begin_Chunk(W3D_CHUNK_AABTREE_HEADER);
W3dMeshAABTreeHeader header;
memset(&header,0,sizeof(header));
header.NodeCount = Node_Count();
header.PolyCount = Poly_Count();
csave.Write(&header,sizeof(header));
csave.End_Chunk();
/*
** Write out the array of polygon indices
*/
csave.Begin_Chunk(W3D_CHUNK_AABTREE_POLYINDICES);
csave.Write(poly_indices,Poly_Count() * sizeof(uint32));
csave.End_Chunk();
/*
** Write out the array of nodes
*/
csave.Begin_Chunk(W3D_CHUNK_AABTREE_NODES);
for (int ni=0; niIndex]);
newnode->Min.X = node->Min.X;
newnode->Min.Y = node->Min.Y;
newnode->Min.Z = node->Min.Z;
newnode->Max.X = node->Max.X;
newnode->Max.Y = node->Max.Y;
newnode->Max.Z = node->Max.Z;
/*
** If this is a non-leaf node, set up the child indices, otherwise set up the polygon indices
*/
if (node->Front != NULL) {
WWASSERT(node->Back != NULL); // if we have one child, we better have both!
newnode->FrontOrPoly0 = node->Front->Index;
newnode->BackOrPolyCount = node->Back->Index;
} else {
newnode->FrontOrPoly0 = cur_poly | 0x80000000;
newnode->BackOrPolyCount = node->PolyCount;
}
/*
** Copy the polygon indices for this node into our array
*/
for (int pcounter = 0; pcounter < node->PolyCount; pcounter++) {
poly_indices[cur_poly++] = node->PolyIndices[pcounter];
}
/*
** Install the children
*/
if (node->Front) {
Build_W3D_AABTree_Recursive(node->Front,w3d_nodes,poly_indices,cur_node,cur_poly);
}
if (node->Back) {
Build_W3D_AABTree_Recursive(node->Back,w3d_nodes,poly_indices,cur_node,cur_poly);
}
}