ULRE/3rdpty/NvTriStrip/NvTriStrip.cpp
2019-04-29 20:06:30 +08:00

500 lines
15 KiB
C++

#include "NvTriStripObjects.h"
#include "NvTriStrip.h"
namespace NvTriStrip
{
////////////////////////////////////////////////////////////////////////////////////////
//private data
static unsigned int cacheSize = CACHESIZE_GEFORCE3_6;
static bool bStitchStrips = true;
static unsigned int minStripSize = 0;
static bool bListsOnly = false;
static unsigned int restartVal = 0;
static bool bRestart = false;
void EnableRestart(const unsigned int _restartVal)
{
bRestart = true;
restartVal = _restartVal;
}
void DisableRestart()
{
bRestart = false;
}
////////////////////////////////////////////////////////////////////////////////////////
// SetListsOnly()
//
// If set to true, will return an optimized list, with no strips at all.
//
// Default value: false
//
void SetListsOnly(const bool _bListsOnly)
{
bListsOnly = _bListsOnly;
}
////////////////////////////////////////////////////////////////////////////////////////
// SetCacheSize()
//
// Sets the cache size which the stripfier uses to optimize the data.
// Controls the length of the generated individual strips.
// This is the "actual" cache size, so 24 for GeForce3 and 16 for GeForce1/2
// You may want to play around with this number to tweak performance.
//
// Default value: 16
//
void SetCacheSize(const unsigned int _cacheSize)
{
cacheSize = _cacheSize;
}
////////////////////////////////////////////////////////////////////////////////////////
// SetStitchStrips()
//
// bool to indicate whether to stitch together strips into one huge strip or not.
// If set to true, you'll get back one huge strip stitched together using degenerate
// triangles.
// If set to false, you'll get back a large number of separate strips.
//
// Default value: true
//
void SetStitchStrips(const bool _bStitchStrips)
{
bStitchStrips = _bStitchStrips;
}
////////////////////////////////////////////////////////////////////////////////////////
// SetMinStripSize()
//
// Sets the minimum acceptable size for a strip, in triangles.
// All strips generated which are shorter than this will be thrown into one big, separate list.
//
// Default value: 0
//
void SetMinStripSize(const unsigned int _minStripSize)
{
minStripSize = _minStripSize;
}
////////////////////////////////////////////////////////////////////////////////////////
//Cleanup strips / faces, used by generatestrips
void Cleanup(NvStripInfoVec& tempStrips, NvFaceInfoVec& tempFaces)
{
//delete strips
for(unsigned int i = 0; i < tempStrips.size(); i++)
{
for(unsigned int j = 0; j < tempStrips[i]->m_faces.size(); j++)
{
delete tempStrips[i]->m_faces[j];
tempStrips[i]->m_faces[j] = nullptr;
}
tempStrips[i]->m_faces.resize(0);
delete tempStrips[i];
tempStrips[i] = nullptr;
}
//delete faces
for(unsigned int i = 0; i < tempFaces.size(); i++)
{
delete tempFaces[i];
tempFaces[i] = nullptr;
}
}
////////////////////////////////////////////////////////////////////////////////////////
//SameTriangle()
//
//Returns true if the two triangles defined by firstTri and secondTri are the same
// The "same" is defined in this case as having the same indices with the same winding order
//
bool SameTriangle(unsigned short firstTri0, unsigned short firstTri1, unsigned short firstTri2,
unsigned short secondTri0, unsigned short secondTri1, unsigned short secondTri2)
{
bool isSame = false;
if (firstTri0 == secondTri0)
{
if (firstTri1 == secondTri1)
{
if (firstTri2 == secondTri2)
isSame = true;
}
}
else if (firstTri0 == secondTri1)
{
if (firstTri1 == secondTri2)
{
if (firstTri2 == secondTri0)
isSame = true;
}
}
else if (firstTri0 == secondTri2)
{
if (firstTri1 == secondTri0)
{
if (firstTri2 == secondTri1)
isSame = true;
}
}
return isSame;
}
bool TestTriangle(const unsigned short v0, const unsigned short v1, const unsigned short v2, const std::vector<NvFaceInfo>* in_bins, const int NUMBINS)
{
//hash this triangle
bool isLegit = false;
int ctr = v0 % NUMBINS;
for (unsigned int k = 0; k < in_bins[ctr].size(); ++k)
{
//check triangles in this bin
if (SameTriangle(in_bins[ctr][k].m_v0, in_bins[ctr][k].m_v1, in_bins[ctr][k].m_v2,
v0, v1, v2))
{
isLegit = true;
break;
}
}
if (!isLegit)
{
ctr = v1 % NUMBINS;
for (unsigned int k = 0; k < in_bins[ctr].size(); ++k)
{
//check triangles in this bin
if (SameTriangle(in_bins[ctr][k].m_v0, in_bins[ctr][k].m_v1, in_bins[ctr][k].m_v2,
v0, v1, v2))
{
isLegit = true;
break;
}
}
if (!isLegit)
{
ctr = v2 % NUMBINS;
for (unsigned int k = 0; k < in_bins[ctr].size(); ++k)
{
//check triangles in this bin
if (SameTriangle(in_bins[ctr][k].m_v0, in_bins[ctr][k].m_v1, in_bins[ctr][k].m_v2,
v0, v1, v2))
{
isLegit = true;
break;
}
}
}
}
return isLegit;
}
////////////////////////////////////////////////////////////////////////////////////////
// GenerateStrips()
//
// in_indices: input index list, the indices you would use to render
// in_numIndices: number of entries in in_indices
// primGroups: array of optimized/stripified PrimitiveGroups
// numGroups: number of groups returned
//
// Be sure to call delete[] on the returned primGroups to avoid leaking mem
//
bool GenerateStrips(const unsigned short* in_indices, const unsigned int in_numIndices,
PrimitiveGroup** primGroups, unsigned short* numGroups, bool validateEnabled)
{
//put data in format that the stripifier likes
WordVec tempIndices;
tempIndices.resize(in_numIndices);
unsigned short maxIndex = 0;
unsigned short minIndex = 0xFFFF;
for(unsigned int i = 0; i < in_numIndices; i++)
{
tempIndices[i] = in_indices[i];
if (in_indices[i] > maxIndex)
maxIndex = in_indices[i];
if (in_indices[i] < minIndex)
minIndex = in_indices[i];
}
NvStripInfoVec tempStrips;
NvFaceInfoVec tempFaces;
NvStripifier stripifier;
//do actual stripification
stripifier.Stripify(tempIndices, cacheSize, minStripSize, maxIndex, tempStrips, tempFaces);
//stitch strips together
IntVec stripIndices;
unsigned int numSeparateStrips = 0;
if(bListsOnly)
{
//if we're outputting only lists, we're done
*numGroups = 1;
(*primGroups) = new PrimitiveGroup[*numGroups];
PrimitiveGroup* primGroupArray = *primGroups;
//count the total number of indices
unsigned int numIndices = 0;
for(unsigned int i = 0; i < tempStrips.size(); i++)
{
numIndices += tempStrips[i]->m_faces.size() * 3;
}
//add in the list
numIndices += tempFaces.size() * 3;
primGroupArray[0].type = PT_LIST;
primGroupArray[0].numIndices = numIndices;
primGroupArray[0].indices = new unsigned short[numIndices];
//do strips
unsigned int indexCtr = 0;
for(unsigned int i = 0; i < tempStrips.size(); i++)
{
for(unsigned int j = 0; j < tempStrips[i]->m_faces.size(); j++)
{
//degenerates are of no use with lists
if(!NvStripifier::IsDegenerate(tempStrips[i]->m_faces[j]))
{
primGroupArray[0].indices[indexCtr++] = tempStrips[i]->m_faces[j]->m_v0;
primGroupArray[0].indices[indexCtr++] = tempStrips[i]->m_faces[j]->m_v1;
primGroupArray[0].indices[indexCtr++] = tempStrips[i]->m_faces[j]->m_v2;
}
else
{
//we've removed a tri, reduce the number of indices
primGroupArray[0].numIndices -= 3;
}
}
}
//do lists
for(unsigned int i = 0; i < tempFaces.size(); i++)
{
primGroupArray[0].indices[indexCtr++] = tempFaces[i]->m_v0;
primGroupArray[0].indices[indexCtr++] = tempFaces[i]->m_v1;
primGroupArray[0].indices[indexCtr++] = tempFaces[i]->m_v2;
}
}
else
{
stripifier.CreateStrips(tempStrips, stripIndices, bStitchStrips, numSeparateStrips, bRestart, restartVal);
//if we're stitching strips together, we better get back only one strip from CreateStrips()
assert( (bStitchStrips && (numSeparateStrips == 1)) || !bStitchStrips);
//convert to output format
*numGroups = numSeparateStrips; //for the strips
if(tempFaces.size() != 0)
(*numGroups)++; //we've got a list as well, increment
(*primGroups) = new PrimitiveGroup[*numGroups];
PrimitiveGroup* primGroupArray = *primGroups;
//first, the strips
int startingLoc = 0;
for(unsigned int stripCtr = 0; stripCtr < numSeparateStrips; stripCtr++)
{
int stripLength = 0;
if(!bStitchStrips)
{
//if we've got multiple strips, we need to figure out the correct length
unsigned int i;
for(i = startingLoc; i < stripIndices.size(); i++)
{
if(stripIndices[i] == -1)
break;
}
stripLength = i - startingLoc;
}
else
stripLength = stripIndices.size();
primGroupArray[stripCtr].type = PT_STRIP;
primGroupArray[stripCtr].indices = new unsigned short[stripLength];
primGroupArray[stripCtr].numIndices = stripLength;
int indexCtr = 0;
for(int i = startingLoc; i < stripLength + startingLoc; i++)
primGroupArray[stripCtr].indices[indexCtr++] = stripIndices[i];
//we add 1 to account for the -1 separating strips
//this doesn't break the stitched case since we'll exit the loop
startingLoc += stripLength + 1;
}
//next, the list
if(tempFaces.size() != 0)
{
int faceGroupLoc = (*numGroups) - 1; //the face group is the last one
primGroupArray[faceGroupLoc].type = PT_LIST;
primGroupArray[faceGroupLoc].indices = new unsigned short[tempFaces.size() * 3];
primGroupArray[faceGroupLoc].numIndices = tempFaces.size() * 3;
int indexCtr = 0;
for(unsigned int i = 0; i < tempFaces.size(); i++)
{
primGroupArray[faceGroupLoc].indices[indexCtr++] = tempFaces[i]->m_v0;
primGroupArray[faceGroupLoc].indices[indexCtr++] = tempFaces[i]->m_v1;
primGroupArray[faceGroupLoc].indices[indexCtr++] = tempFaces[i]->m_v2;
}
}
}
//validate generated data against input
if (validateEnabled)
{
const int NUMBINS = 100;
std::vector<NvFaceInfo> in_bins[NUMBINS];
//hash input indices on first index
for (unsigned int i = 0; i < in_numIndices; i += 3)
{
NvFaceInfo faceInfo(in_indices[i], in_indices[i + 1], in_indices[i + 2]);
in_bins[in_indices[i] % NUMBINS].push_back(faceInfo);
}
for (int i = 0; i < *numGroups; ++i)
{
switch ((*primGroups)[i].type)
{
case PT_LIST:
{
for (unsigned int j = 0; j < (*primGroups)[i].numIndices; j += 3)
{
unsigned short v0 = (*primGroups)[i].indices[j];
unsigned short v1 = (*primGroups)[i].indices[j + 1];
unsigned short v2 = (*primGroups)[i].indices[j + 2];
//ignore degenerates
if (NvStripifier::IsDegenerate(v0, v1, v2))
continue;
if (!TestTriangle(v0, v1, v2, in_bins, NUMBINS))
{
Cleanup(tempStrips, tempFaces);
return false;
}
}
break;
}
case PT_STRIP:
{
int brokenCtr = 0;
bool flip = false;
for (unsigned int j = 2; j < (*primGroups)[i].numIndices; ++j)
{
unsigned short v0 = (*primGroups)[i].indices[j - 2];
unsigned short v1 = (*primGroups)[i].indices[j - 1];
unsigned short v2 = (*primGroups)[i].indices[j];
if (flip)
{
//swap v1 and v2
unsigned short swap = v1;
v1 = v2;
v2 = swap;
}
//ignore degenerates
if (NvStripifier::IsDegenerate(v0, v1, v2))
{
flip = !flip;
continue;
}
if (!TestTriangle(v0, v1, v2, in_bins, NUMBINS))
{
Cleanup(tempStrips, tempFaces);
return false;
}
flip = !flip;
}
break;
}
case PT_FAN:
default:
break;
}
}
}
//clean up everything
Cleanup(tempStrips, tempFaces);
return true;
}
////////////////////////////////////////////////////////////////////////////////////////
// RemapIndices()
//
// Function to remap your indices to improve spatial locality in your vertex buffer.
//
// in_primGroups: array of PrimitiveGroups you want remapped
// numGroups: number of entries in in_primGroups
// numVerts: number of vertices in your vertex buffer, also can be thought of as the range
// of acceptable values for indices in your primitive groups.
// remappedGroups: array of remapped PrimitiveGroups
//
// Note that, according to the remapping handed back to you, you must reorder your
// vertex buffer.
//
void RemapIndices(const PrimitiveGroup* in_primGroups, const unsigned short numGroups,
const unsigned short numVerts, PrimitiveGroup** remappedGroups)
{
(*remappedGroups) = new PrimitiveGroup[numGroups];
//caches oldIndex --> newIndex conversion
int *indexCache;
indexCache = new int[numVerts];
memset(indexCache, -1, sizeof(int)*numVerts);
//loop over primitive groups
unsigned int indexCtr = 0;
for(int i = 0; i < numGroups; i++)
{
unsigned int numIndices = in_primGroups[i].numIndices;
//init remapped group
(*remappedGroups)[i].type = in_primGroups[i].type;
(*remappedGroups)[i].numIndices = numIndices;
(*remappedGroups)[i].indices = new unsigned short[numIndices];
for(unsigned int j = 0; j < numIndices; j++)
{
int cachedIndex = indexCache[in_primGroups[i].indices[j]];
if(cachedIndex == -1) //we haven't seen this index before
{
//point to "last" vertex in VB
(*remappedGroups)[i].indices[j] = indexCtr;
//add to index cache, increment
indexCache[in_primGroups[i].indices[j]] = indexCtr++;
}
else
{
//we've seen this index before
(*remappedGroups)[i].indices[j] = cachedIndex;
}
}
}
delete[] indexCache;
}
}//namespace NvTriStrip