vec Plane::ClosestPoint(const LineSegment &lineSegment) const
{
/*
///@todo Output parametric d as well.
float d;
if (lineSegment.Intersects(*this, &d))
return lineSegment.GetPoint(d);
else
if (Distance(lineSegment.a) < Distance(lineSegment.b))
return Project(lineSegment.a);
else
return Project(lineSegment.b);
*/
assume(lineSegment.IsFinite());
assume(!IsDegenerate());
float aDist = Dot(normal, lineSegment.a);
float bDist = Dot(normal, lineSegment.b);
float denom = bDist - aDist;
if (EqualAbs(denom, 0.f))
return Project(Abs(aDist) < Abs(bDist) ? lineSegment.a : lineSegment.b); // Project()ing the result here is not strictly necessary,
// but done for numerical stability, so that Plane::Contains()
// will return true for the returned point.
else
{
///@todo Output parametric t along the ray as well.
float t = (d - Dot(normal, lineSegment.a)) / (bDist - aDist);
t = Clamp01(t);
// Project()ing the result here is necessary only if we clamped, but done for numerical stability, so that Plane::Contains() will
// return true for the returned point.
return Project(lineSegment.GetPoint(t));
}
}
float3 Triangle::RandomPointOnEdge(LCG &rng) const
{
assume(!IsDegenerate());
float ab = a.Distance(b);
float bc = b.Distance(c);
float ca = c.Distance(a);
float r = rng.Float(0, ab + bc + ca);
if (r < ab)
return a + (b-a) * r / ab;
r -= ab;
if (r < bc)
return b + (c-b) * r / bc;
r -= bc;
return c + (a-c) * r / ca;
}
vec Plane::ClosestPoint(const Ray &ray) const
{
assume(ray.IsFinite());
assume(!IsDegenerate());
// The plane and a ray have three configurations:
// 1) the ray and the plane don't intersect: the closest point is the ray origin point.
// 2) the ray and the plane do intersect: the closest point is the intersection point.
// 3) the ray is parallel to the plane: any point on the ray projected to the plane is a closest point.
float denom = Dot(normal, ray.dir);
if (denom == 0.f)
return Project(ray.pos); // case 3)
float t = (d - Dot(normal, ray.pos)) / denom;
if (t >= 0.f && t < 1e6f) // Numerical stability check: Instead of checking denom against epsilon, check the resulting t for very large values.
return ray.GetPoint(t); // case 2)
else
return Project(ray.pos); // case 1)
}
////////////////////////////////////////////////////////////////////////////////////////
// CreateStrips()
//
// Generates actual strips from the list-in-strip-order.
//
void NvStripifier::CreateStrips(const NvStripInfoVec& allStrips, IntVec& stripIndices,
const bool bStitchStrips, unsigned int& numSeparateStrips,
const bool bRestart, const unsigned int restartVal)
{
assert(numSeparateStrips == 0);
NvFaceInfo tLastFace(0, 0, 0);
NvFaceInfo tPrevStripLastFace(0, 0, 0);
size_t nStripCount = allStrips.size();
//we infer the cw/ccw ordering depending on the number of indices
//this is screwed up by the fact that we insert -1s to denote changing strips
//this is to account for that
int accountForNegatives = 0;
for (size_t i = 0; i < nStripCount; i++)
{
NvStripInfo *strip = allStrips[i];
int nStripFaceCount = strip->m_faces.size();
assert(nStripFaceCount > 0);
// Handle the first face in the strip
{
NvFaceInfo tFirstFace(strip->m_faces[0]->m_v0, strip->m_faces[0]->m_v1, strip->m_faces[0]->m_v2);
// If there is a second face, reorder vertices such that the
// unique vertex is first
if (nStripFaceCount > 1)
{
int nUnique = NvStripifier::GetUniqueVertexInB(strip->m_faces[1], &tFirstFace);
if (nUnique == tFirstFace.m_v1)
{
SWAP(tFirstFace.m_v0, tFirstFace.m_v1);
}
else if (nUnique == tFirstFace.m_v2)
{
SWAP(tFirstFace.m_v0, tFirstFace.m_v2);
}
// If there is a third face, reorder vertices such that the
// shared vertex is last
if (nStripFaceCount > 2)
{
if(IsDegenerate(strip->m_faces[1]))
{
int pivot = strip->m_faces[1]->m_v1;
if(tFirstFace.m_v1 == pivot)
{
SWAP(tFirstFace.m_v1, tFirstFace.m_v2);
}
}
else
{
int nShared0, nShared1;
GetSharedVertices(strip->m_faces[2], &tFirstFace, &nShared0, &nShared1);
if ( (nShared0 == tFirstFace.m_v1) && (nShared1 == -1) )
{
SWAP(tFirstFace.m_v1, tFirstFace.m_v2);
}
}
}
}
if( (i == 0) || !bStitchStrips || bRestart)
{
if(!IsCW(strip->m_faces[0], tFirstFace.m_v0, tFirstFace.m_v1))
stripIndices.push_back(tFirstFace.m_v0);
}
else
{
// Double tap the first in the new strip
stripIndices.push_back(tFirstFace.m_v0);
// Check CW/CCW ordering
if (NextIsCW(stripIndices.size() - accountForNegatives) != IsCW(strip->m_faces[0], tFirstFace.m_v0, tFirstFace.m_v1))
{
stripIndices.push_back(tFirstFace.m_v0);
}
}
stripIndices.push_back(tFirstFace.m_v0);
stripIndices.push_back(tFirstFace.m_v1);
stripIndices.push_back(tFirstFace.m_v2);
// Update last face info
tLastFace = tFirstFace;
}
for (int j = 1; j < nStripFaceCount; j++)
{
int nUnique = GetUniqueVertexInB(&tLastFace, strip->m_faces[j]);
if (nUnique != -1)
{
stripIndices.push_back(nUnique);
// Update last face info
tLastFace.m_v0 = tLastFace.m_v1;
tLastFace.m_v1 = tLastFace.m_v2;
tLastFace.m_v2 = nUnique;
}
else
{
//we've hit a degenerate
stripIndices.push_back(strip->m_faces[j]->m_v2);
tLastFace.m_v0 = strip->m_faces[j]->m_v0;//tLastFace.m_v1;
tLastFace.m_v1 = strip->m_faces[j]->m_v1;//tLastFace.m_v2;
tLastFace.m_v2 = strip->m_faces[j]->m_v2;//tLastFace.m_v1;
}
}
// Double tap between strips.
if (bStitchStrips && !bRestart)
{
if (i != nStripCount - 1)
stripIndices.push_back(tLastFace.m_v2);
}
else if (bRestart)
{
stripIndices.push_back(restartVal);
}
else
{
//-1 index indicates next strip
stripIndices.push_back(-1);
accountForNegatives++;
numSeparateStrips++;
}
// Update last face info
tLastFace.m_v0 = tLastFace.m_v1;
tLastFace.m_v1 = tLastFace.m_v2;
tLastFace.m_v2 = tLastFace.m_v2;
}
if(bStitchStrips || bRestart)
numSeparateStrips = 1;
}
///////////////////////////////////////////////////////////////////////////////////////////
// BuildStripifyInfo()
//
// Builds the list of all face and edge infos
//
void NvStripifier::BuildStripifyInfo(NvFaceInfoVec &faceInfos, NvEdgeInfoVec &edgeInfos,
const unsigned short maxIndex)
{
// reserve space for the face infos, but do not resize them.
int numIndices = indices.size();
faceInfos.reserve(numIndices / 3);
// we actually resize the edge infos, so we must initialize to NULL
edgeInfos.resize(maxIndex + 1);
for (unsigned short i = 0; i < maxIndex + 1; i++)
edgeInfos[i] = NULL;
// iterate through the triangles of the triangle list
int numTriangles = numIndices / 3;
int index = 0;
bool bFaceUpdated[3];
for (int i = 0; i < numTriangles; i++)
{
bool bMightAlreadyExist = true;
bFaceUpdated[0] = false;
bFaceUpdated[1] = false;
bFaceUpdated[2] = false;
// grab the indices
int v0 = indices[index++];
int v1 = indices[index++];
int v2 = indices[index++];
//we disregard degenerates
if(IsDegenerate(v0, v1, v2))
continue;
// create the face info and add it to the list of faces, but only if this exact face doesn't already
// exist in the list
NvFaceInfo *faceInfo = new NvFaceInfo(v0, v1, v2);
// grab the edge infos, creating them if they do not already exist
NvEdgeInfo *edgeInfo01 = FindEdgeInfo(edgeInfos, v0, v1);
if (edgeInfo01 == NULL)
{
//since one of it's edges isn't in the edge data structure, it can't already exist in the face structure
bMightAlreadyExist = false;
// create the info
edgeInfo01 = new NvEdgeInfo(v0, v1);
// update the linked list on both
edgeInfo01->m_nextV0 = edgeInfos[v0];
edgeInfo01->m_nextV1 = edgeInfos[v1];
edgeInfos[v0] = edgeInfo01;
edgeInfos[v1] = edgeInfo01;
// set face 0
edgeInfo01->m_face0 = faceInfo;
}
else
{
if (edgeInfo01->m_face1 != NULL)
{
printf("BuildStripifyInfo: > 2 triangles on an edge... uncertain consequences\n");
}
else
{
edgeInfo01->m_face1 = faceInfo;
bFaceUpdated[0] = true;
}
}
// grab the edge infos, creating them if they do not already exist
NvEdgeInfo *edgeInfo12 = FindEdgeInfo(edgeInfos, v1, v2);
if (edgeInfo12 == NULL)
{
bMightAlreadyExist = false;
// create the info
edgeInfo12 = new NvEdgeInfo(v1, v2);
// update the linked list on both
edgeInfo12->m_nextV0 = edgeInfos[v1];
edgeInfo12->m_nextV1 = edgeInfos[v2];
edgeInfos[v1] = edgeInfo12;
edgeInfos[v2] = edgeInfo12;
// set face 0
edgeInfo12->m_face0 = faceInfo;
}
else
{
if (edgeInfo12->m_face1 != NULL)
{
printf("BuildStripifyInfo: > 2 triangles on an edge... uncertain consequences\n");
}
else
{
edgeInfo12->m_face1 = faceInfo;
bFaceUpdated[1] = true;
}
}
// grab the edge infos, creating them if they do not already exist
NvEdgeInfo *edgeInfo20 = FindEdgeInfo(edgeInfos, v2, v0);
if (edgeInfo20 == NULL)
{
bMightAlreadyExist = false;
// create the info
edgeInfo20 = new NvEdgeInfo(v2, v0);
// update the linked list on both
edgeInfo20->m_nextV0 = edgeInfos[v2];
edgeInfo20->m_nextV1 = edgeInfos[v0];
edgeInfos[v2] = edgeInfo20;
edgeInfos[v0] = edgeInfo20;
// set face 0
edgeInfo20->m_face0 = faceInfo;
}
else
{
if (edgeInfo20->m_face1 != NULL)
{
printf("BuildStripifyInfo: > 2 triangles on an edge... uncertain consequences\n");
}
else
{
edgeInfo20->m_face1 = faceInfo;
bFaceUpdated[2] = true;
}
}
if(bMightAlreadyExist)
{
if(!AlreadyExists(faceInfo, faceInfos))
faceInfos.push_back(faceInfo);
else
{
delete faceInfo;
//cleanup pointers that point to this deleted face
if(bFaceUpdated[0])
edgeInfo01->m_face1 = NULL;
if(bFaceUpdated[1])
edgeInfo12->m_face1 = NULL;
if(bFaceUpdated[2])
edgeInfo20->m_face1 = NULL;
}
}
else
{
faceInfos.push_back(faceInfo);
}
}
}
///////////////////////////////////////////////////////////////////////////////////////////
// SplitUpStripsAndOptimize()
//
// Splits the input vector of strips (allBigStrips) into smaller, cache friendly pieces, then
// reorders these pieces to maximize cache hits
// The final strips are output through outStrips
//
void NvStripifier::SplitUpStripsAndOptimize(NvStripInfoVec &allStrips, NvStripInfoVec &outStrips,
NvEdgeInfoVec& edgeInfos, NvFaceInfoVec& outFaceList)
{
int threshold = cacheSize;
NvStripInfoVec tempStrips;
//split up strips into threshold-sized pieces
for(size_t i = 0; i < allStrips.size(); i++)
{
NvStripInfo* currentStrip;
NvStripStartInfo startInfo(NULL, NULL, false);
int actualStripSize = 0;
for(size_t j = 0; j < allStrips[i]->m_faces.size(); ++j)
{
if( !IsDegenerate(allStrips[i]->m_faces[j]) )
actualStripSize++;
}
if(actualStripSize /*allStrips[i]->m_faces.size()*/ > threshold)
{
int numTimes = actualStripSize /*allStrips[i]->m_faces.size()*/ / threshold;
int numLeftover = actualStripSize /*allStrips[i]->m_faces.size()*/ % threshold;
int degenerateCount = 0;
int j = 0;
for(; j < numTimes; j++)
{
currentStrip = new NvStripInfo(startInfo, 0, -1);
int faceCtr = j*threshold + degenerateCount;
bool bFirstTime = true;
while(faceCtr < threshold+(j*threshold)+degenerateCount)
{
if(IsDegenerate(allStrips[i]->m_faces[faceCtr]))
{
degenerateCount++;
//last time or first time through, no need for a degenerate
if( (((faceCtr + 1) != threshold+(j*threshold)+degenerateCount) ||
((j == numTimes - 1) && (numLeftover < 4) && (numLeftover > 0))) &&
!bFirstTime)
{
currentStrip->m_faces.push_back(allStrips[i]->m_faces[faceCtr++]);
}
else
{
//but, we do need to delete the degenerate, if it's marked fake, to avoid leaking
if(allStrips[i]->m_faces[faceCtr]->m_bIsFake)
{
delete allStrips[i]->m_faces[faceCtr], allStrips[i]->m_faces[faceCtr] = NULL;
}
++faceCtr;
}
}
else
{
currentStrip->m_faces.push_back(allStrips[i]->m_faces[faceCtr++]);
bFirstTime = false;
}
}
/*
for(int faceCtr = j*threshold; faceCtr < threshold+(j*threshold); faceCtr++)
{
currentStrip->m_faces.push_back(allStrips[i]->m_faces[faceCtr]);
}
*/
if(j == numTimes - 1) //last time through
{
if( (numLeftover < 4) && (numLeftover > 0) ) //way too small
{
//just add to last strip
int ctr = 0;
while(ctr < numLeftover)
{
IsDegenerate( allStrips[i]->m_faces[faceCtr] ) ? ++degenerateCount : ++ctr;
currentStrip->m_faces.push_back(allStrips[i]->m_faces[faceCtr++]);
}
numLeftover = 0;
}
}
tempStrips.push_back(currentStrip);
}
int leftOff = j * threshold + degenerateCount;
if(numLeftover != 0)
{
currentStrip = new NvStripInfo(startInfo, 0, -1);
int ctr = 0;
bool bFirstTime = true;
while(ctr < numLeftover)
{
if( !IsDegenerate(allStrips[i]->m_faces[leftOff]) )
{
ctr++;
bFirstTime = false;
currentStrip->m_faces.push_back(allStrips[i]->m_faces[leftOff++]);
}
else if(!bFirstTime)
currentStrip->m_faces.push_back(allStrips[i]->m_faces[leftOff++]);
else
{
//don't leak
if(allStrips[i]->m_faces[leftOff]->m_bIsFake)
{
delete allStrips[i]->m_faces[leftOff], allStrips[i]->m_faces[leftOff] = NULL;
}
leftOff++;
}
}
/*
for(size_t k = 0; k < numLeftover; k++)
{
currentStrip->m_faces.push_back(allStrips[i]->m_faces[leftOff++]);
}
*/
tempStrips.push_back(currentStrip);
}
}
else
{
//we're not just doing a tempStrips.push_back(allBigStrips[i]) because
// this way we can delete allBigStrips later to free the memory
currentStrip = new NvStripInfo(startInfo, 0, -1);
for(size_t j = 0; j < allStrips[i]->m_faces.size(); j++)
currentStrip->m_faces.push_back(allStrips[i]->m_faces[j]);
tempStrips.push_back(currentStrip);
}
}
//add small strips to face list
NvStripInfoVec tempStrips2;
RemoveSmallStrips(tempStrips, tempStrips2, outFaceList);
outStrips.clear();
//screw optimization for now
// for(size_t i = 0; i < tempStrips.size(); ++i)
// outStrips.push_back(tempStrips[i]);
if(tempStrips2.size() != 0)
{
//Optimize for the vertex cache
VertexCache* vcache = new VertexCache(cacheSize);
float bestNumHits = -1.0f;
float numHits;
int bestIndex;
bool done = false;
int firstIndex = 0;
float minCost = 10000.0f;
for(size_t i = 0; i < tempStrips2.size(); i++)
{
int numNeighbors = 0;
//find strip with least number of neighbors per face
for(size_t j = 0; j < tempStrips2[i]->m_faces.size(); j++)
{
numNeighbors += NumNeighbors(tempStrips2[i]->m_faces[j], edgeInfos);
}
float currCost = (float)numNeighbors / (float)tempStrips2[i]->m_faces.size();
if(currCost < minCost)
{
minCost = currCost;
firstIndex = i;
}
}
UpdateCacheStrip(vcache, tempStrips2[firstIndex]);
outStrips.push_back(tempStrips2[firstIndex]);
tempStrips2[firstIndex]->visited = true;
bool bWantsCW = (tempStrips2[firstIndex]->m_faces.size() % 2) == 0;
//this n^2 algo is what slows down stripification so much....
// needs to be improved
while(1)
{
bestNumHits = -1.0f;
//find best strip to add next, given the current cache
for(size_t i = 0; i < tempStrips2.size(); i++)
{
if(tempStrips2[i]->visited)
continue;
numHits = CalcNumHitsStrip(vcache, tempStrips2[i]);
if(numHits > bestNumHits)
{
bestNumHits = numHits;
bestIndex = i;
}
else if(numHits >= bestNumHits)
{
//check previous strip to see if this one requires it to switch polarity
NvStripInfo *strip = tempStrips2[i];
int nStripFaceCount = strip->m_faces.size();
NvFaceInfo tFirstFace(strip->m_faces[0]->m_v0, strip->m_faces[0]->m_v1, strip->m_faces[0]->m_v2);
// If there is a second face, reorder vertices such that the
// unique vertex is first
if (nStripFaceCount > 1)
{
int nUnique = NvStripifier::GetUniqueVertexInB(strip->m_faces[1], &tFirstFace);
if (nUnique == tFirstFace.m_v1)
{
SWAP(tFirstFace.m_v0, tFirstFace.m_v1);
}
else if (nUnique == tFirstFace.m_v2)
{
SWAP(tFirstFace.m_v0, tFirstFace.m_v2);
}
// If there is a third face, reorder vertices such that the
// shared vertex is last
if (nStripFaceCount > 2)
{
int nShared0, nShared1;
GetSharedVertices(strip->m_faces[2], &tFirstFace, &nShared0, &nShared1);
if ( (nShared0 == tFirstFace.m_v1) && (nShared1 == -1) )
{
SWAP(tFirstFace.m_v1, tFirstFace.m_v2);
}
}
}
// Check CW/CCW ordering
if (bWantsCW == IsCW(strip->m_faces[0], tFirstFace.m_v0, tFirstFace.m_v1))
{
//I like this one!
bestIndex = i;
}
}
}
if(bestNumHits == -1.0f)
break;
tempStrips2[bestIndex]->visited = true;
UpdateCacheStrip(vcache, tempStrips2[bestIndex]);
outStrips.push_back(tempStrips2[bestIndex]);
bWantsCW = (tempStrips2[bestIndex]->m_faces.size() % 2 == 0) ? bWantsCW : !bWantsCW;
}
delete vcache;
}
}
bool Triangle::IsDegenerate(float /*epsilon*/) const
{
return IsDegenerate(a, b, c);
}
bool Triangle::IsDegenerate(float epsilon) const
{
return IsDegenerate(a, b, c, epsilon);
}
