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Final changes for Quads and NGons. computeBoundaryIntersection variab…
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…le is added to ChartOptions.
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@mifth
mifth committed Nov 4, 2024
1 parent 710357a commit 22f4d64
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Showing 3 changed files with 128 additions and 17 deletions.
142 changes: 125 additions & 17 deletions source/xatlas/xatlas.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2798,6 +2798,9 @@ class Mesh
HashMap<EdgeKey, EdgeHash> m_edgeMap;

public:
// Quads/NGons IDs. Triangle id is a number, Quad/NGon id is a value. It can be empty if there is no polygon mapping.
Array<uint32_t> trianglesToPolygonIDs; // Triangle index (mesh face index) to Quad/NGon index.

class FaceEdgeIterator
{
public:
Expand Down Expand Up @@ -3461,9 +3464,8 @@ struct Triangulator
// also sort the ears by angle, start with the ones that have the smallest angle and proceed in order.
void triangulatePolygon(ConstArrayView<Vector3> vertices, const Array<uint32_t>& inputIndices, Array<uint32_t> &outputIndices, Array<uint32_t> &outindicesIDs)
{
m_polygonVertices.clear();
m_polygonVertices.reserve(inputIndices.size());
outputIndices.clear();
outindicesIDs.clear();
if (inputIndices.size() == 3) {
// Simple case for triangles.
outputIndices.push_back(inputIndices[0]);
Expand All @@ -3473,6 +3475,21 @@ struct Triangulator
outindicesIDs.push_back(1);
outindicesIDs.push_back(2);
}
else if (inputIndices.size() == 3) {
// Simple case for quads.
outputIndices.push_back(inputIndices[0]);
outputIndices.push_back(inputIndices[1]);
outputIndices.push_back(inputIndices[2]);
outindicesIDs.push_back(0);
outindicesIDs.push_back(1);
outindicesIDs.push_back(2);
outputIndices.push_back(inputIndices[0]);
outputIndices.push_back(inputIndices[2]);
outputIndices.push_back(inputIndices[3]);
outindicesIDs.push_back(0);
outindicesIDs.push_back(2);
outindicesIDs.push_back(3);
}
else {
// Build 2D polygon projecting vertices onto normal plane.
// Faces are not necesarily planar, this is for example the case, when the face comes from filling a hole. In such cases
Expand All @@ -3488,6 +3505,8 @@ struct Triangulator
m_polygonAngles.reserve(edgeCount);
m_indicesIDs.clear();
m_indicesIDs.reserve(edgeCount);
m_polygonVertices.clear();
m_polygonVertices.reserve(inputIndices.size());
for (uint32_t i = 0; i < inputIndices.size(); i++) {
m_polygonVertices.push_back(inputIndices[i]);
const Vector3 &pos = vertices[inputIndices[i]];
Expand Down Expand Up @@ -5186,14 +5205,22 @@ struct PlanarCharts
m_regionFirstFace.clear();
m_nextRegionFace.resize(faceCount);
m_faceToRegionId.resize(faceCount);
const bool hasQuadsOrNGons = m_data.mesh->trianglesToPolygonIDs.size() > 0 ? true : false;
Array<bool> parsedFaces; // For Quads/NGons
if (hasQuadsOrNGons)
parsedFaces.resize(faceCount);
for (uint32_t f = 0; f < faceCount; f++) {
m_nextRegionFace[f] = f;
m_faceToRegionId[f] = UINT32_MAX;
if (hasQuadsOrNGons)
parsedFaces[f] = false; // Set default value (false)
}
Array<uint32_t> faceStack;
faceStack.reserve(min(faceCount, 16u));
uint32_t regionCount = 0;
for (uint32_t f = 0; f < faceCount; f++) {
if (hasQuadsOrNGons)
if (parsedFaces[f]) continue; // No need to parse as we already parsed a triangle of a Quad/NGon.
if (m_nextRegionFace[f] != f)
continue; // Already assigned.
if (m_data.isFaceInChart.get(f))
Expand All @@ -5214,6 +5241,19 @@ struct PlanarCharts
continue; // Already assigned.
if (m_data.isFaceInChart.get(oface))
continue; // Already in a chart.
// if Triangle is a part of a Quad/NGon.
if (hasQuadsOrNGons) {
if (m_data.mesh->trianglesToPolygonIDs[face] == m_data.mesh->trianglesToPolygonIDs[oface]) {
const uint32_t next = m_nextRegionFace[face];
m_nextRegionFace[face] = oface;
m_nextRegionFace[oface] = next;
m_faceToRegionId[oface] = regionCount;
faceStack.push_back(oface);
parsedFaces[oface] = true; // set parsed
parsedFaces[face] = true; // set parsed
continue;
}
}
if (!equal(dot(m_data.faceNormals[face], m_data.faceNormals[oface]), 1.0f, kEpsilon))
continue; // Not coplanar.
const uint32_t next = m_nextRegionFace[face];
Expand Down Expand Up @@ -5271,6 +5311,10 @@ struct PlanarCharts
const uint32_t oface = it.oppositeFace();
if (m_faceToRegionId[oface] == region)
continue; // Ignore internal edges.
if (hasQuadsOrNGons) { // Accept an entire NGon. As potentially it should be flat.
if (m_data.mesh->trianglesToPolygonIDs[face] == m_data.mesh->trianglesToPolygonIDs[oface])
continue; // if Triangle is a part of a Quad/NGon.
}
const float angle = m_data.edgeDihedralAngles[it.edge()];
if (angle > 0.0f && angle < FLT_MAX) { // FLT_MAX on boundaries.
createChart = false;
Expand Down Expand Up @@ -5635,21 +5679,28 @@ struct ClusteredCharts
private:
void createChart(float threshold)
{
Chart *chart = XA_NEW(MemTag::Default, Chart);
chart->id = (int)m_charts.size();
m_charts.push_back(chart);
// Pick a face not used by any chart yet, belonging to the largest planar region.
chart->seed = 0;
float largestArea = 0.0f;
for (uint32_t f = 0; f < m_data.mesh->faceCount(); f++) {
const uint32_t faceCount = m_data.mesh->faceCount();
bool isPickedFace = false;
uint32_t seed = 0;
for (uint32_t f = 0; f < faceCount; f++) {
if (m_data.isFaceInChart.get(f))
continue;
const float area = m_planarCharts.regionArea(m_planarCharts.regionIdFromFace(f));
if (area > largestArea) {
largestArea = area;
chart->seed = f;
seed = f;
isPickedFace = true;
}
}
if (!isPickedFace && m_data.isFaceInChart.get(seed))
return; // all faces are already added to charts.
// Create a new Chart and do further changes.
Chart *chart = XA_NEW(MemTag::Default, Chart);
chart->id = (int)m_charts.size();
m_charts.push_back(chart);
chart->seed = seed;
addFaceToChart(chart, chart->seed);
// Grow the chart as much as possible within the given threshold.
for (;;) {
Expand All @@ -5658,7 +5709,7 @@ struct ClusteredCharts
const uint32_t f = chart->candidates.pop();
if (m_data.isFaceInChart.get(f))
continue;
if (!addFaceToChart(chart, f)) {
if (!addFaceToChart(chart, f)) { // If Failed to add a triangle
chart->failedPlanarRegions.push_back(m_planarCharts.regionIdFromFace(f));
continue;
}
Expand Down Expand Up @@ -5747,6 +5798,8 @@ struct ClusteredCharts
XA_DEBUG_ASSERT(!m_data.isFaceInChart.get(face));
const uint32_t oldFaceCount = chart->faces.size();
const bool firstFace = oldFaceCount == 0;
const bool hasQuadsOrNGons = m_data.mesh->trianglesToPolygonIDs.size() > 0 ? true : false;
const uint32_t meshFaceCount = m_data.mesh->faceCount();
// Append the face and any coplanar connected faces to the chart faces array.
chart->faces.push_back(face);
uint32_t coplanarFace = m_planarCharts.nextRegionFace(face);
Expand All @@ -5755,6 +5808,35 @@ struct ClusteredCharts
chart->faces.push_back(coplanarFace);
coplanarFace = m_planarCharts.nextRegionFace(coplanarFace);
}
if (hasQuadsOrNGons) {
// Add missing triangles of Quad/NGon
const uint32_t faceCountTmp = chart->faces.size();
for (uint32_t i = oldFaceCount; i < faceCountTmp; i++) { // Run Forward
const uint32_t i_face = chart->faces[i];
const uint32_t faceQuadOrNGonID = m_data.mesh->trianglesToPolygonIDs[i_face];
const uint32_t nextFace = i_face + 1;
for (uint32_t f = nextFace; f < meshFaceCount; f++) {
if (m_data.mesh->trianglesToPolygonIDs[f] == faceQuadOrNGonID) {
if (!chart->faces.contains(f)) {
chart->faces.push_back(f);
}
}
else {break;}
}
if (i_face > 0) { // Run Backward
int32_t f = static_cast<int32_t>(i_face) - 1;
while (f >= 0) {
if (m_data.mesh->trianglesToPolygonIDs[f] == faceQuadOrNGonID) {
if (!chart->faces.contains(f)) {
chart->faces.push_back(f);
}
}
else {break;}
--f;
}
}
}
}
const uint32_t faceCount = chart->faces.size();
// Compute basis.
Basis basis;
Expand Down Expand Up @@ -7156,6 +7238,9 @@ class Chart
m_originalIndices.resize(faces.length * 3);
// Add geometry.
const uint32_t faceCount = faces.length;
const bool hasQuadsOrNGons = sourceMesh->trianglesToPolygonIDs.size() > 0 ? true : false;
if (hasQuadsOrNGons)
m_unifiedMesh->trianglesToPolygonIDs.resize(faceCount); // Resize an Array Before copying some IDs
for (uint32_t f = 0; f < faceCount; f++) {
uint32_t unifiedIndices[3];
for (uint32_t i = 0; i < 3; i++) {
Expand Down Expand Up @@ -7183,6 +7268,9 @@ class Chart
XA_DEBUG_ASSERT(unifiedIndices[i] != UINT32_MAX);
}
m_unifiedMesh->addFace(unifiedIndices);
// Add TriangleIDs and PolygonIDs
if (hasQuadsOrNGons)
m_unifiedMesh->trianglesToPolygonIDs[f] = sourceMesh->trianglesToPolygonIDs[m_faceToSourceFaceMap[f]];
}
m_unifiedMesh->createBoundaries();
if (m_generatorType == segment::ChartGeneratorType::Planar) {
Expand All @@ -7205,6 +7293,7 @@ class Chart
{
const uint32_t faceCount = faces.length;
m_faceToSourceFaceMap.resize(faceCount);
const bool hasQuadsOrNGons = sourceMesh->trianglesToPolygonIDs.size() > 0 ? true : false;
for (uint32_t i = 0; i < faceCount; i++)
m_faceToSourceFaceMap[i] = parent->m_faceToSourceFaceMap[faces[i]]; // Map faces to parent chart source mesh.
// Copy face indices.
Expand Down Expand Up @@ -7234,6 +7323,8 @@ class Chart
}
// Add faces.
m_originalIndices.resize(faceCount * 3);
if (hasQuadsOrNGons) // NOTE FOR FUTURE! Maybe "parentMesh" should be used instead of "sourceMesh"
m_unifiedMesh->trianglesToPolygonIDs.resize(faceCount); // Resize an Array Before copying some IDs
for (uint32_t f = 0; f < faceCount; f++) {
uint32_t unifiedIndices[3];
for (uint32_t i = 0; i < 3; i++) {
Expand All @@ -7243,6 +7334,9 @@ class Chart
unifiedIndices[i] = sourceVertexToUnifiedVertexMap.get(unifiedVertex);
}
m_unifiedMesh->addFace(unifiedIndices);
// Add TriangleIDs and PolygonIDs
if (hasQuadsOrNGons) // NOTE FOR FUTURE! Maybe "parentMesh" should be used instead of "sourceMesh"
m_unifiedMesh->trianglesToPolygonIDs[f] = sourceMesh->trianglesToPolygonIDs[m_faceToSourceFaceMap[f]];
}
m_unifiedMesh->createBoundaries();
// Need to store texcoords for backup/restore so packing can be run multiple times.
Expand Down Expand Up @@ -7291,7 +7385,8 @@ class Chart
// Computing charts checks for flipped triangles and boundary intersection. Don't need to do that again here if chart is planar.
if (m_type != ChartType::Planar && m_generatorType != segment::ChartGeneratorType::OriginalUv) {
XA_PROFILE_START(parameterizeChartsEvaluateQuality)
m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
if (options.computeBoundaryIntersection) // intersect edges. It can create artifacts (little peeces).
m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
m_quality.computeFlippedFaces(m_unifiedMesh, nullptr);
m_quality.computeMetrics(m_unifiedMesh);
XA_PROFILE_END(parameterizeChartsEvaluateQuality)
Expand All @@ -7308,7 +7403,8 @@ class Chart
computeLeastSquaresConformalMap(m_unifiedMesh);
XA_PROFILE_END(parameterizeChartsLSCM)
XA_PROFILE_START(parameterizeChartsEvaluateQuality)
m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
if (options.computeBoundaryIntersection) // intersect edges. It can create artifacts (little peeces).
m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
#if XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION
m_quality.computeFlippedFaces(m_unifiedMesh, &m_paramFlippedFaces);
#else
Expand Down Expand Up @@ -7680,6 +7776,9 @@ class ChartGroup
const uint32_t approxVertexCount = min(faceCount * 3, m_sourceMesh->vertexCount());
Mesh *mesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, m_sourceMesh->epsilon(), approxVertexCount, faceCount, m_sourceMesh->flags() & MeshFlags::HasNormals);
HashMap<uint32_t, PassthroughHash<uint32_t>> sourceVertexToVertexMap(MemTag::Mesh, approxVertexCount);
const bool hasQuadsOrNGons = m_sourceMesh->trianglesToPolygonIDs.size() > 0 ? true : false;
if (hasQuadsOrNGons)
mesh->trianglesToPolygonIDs.resize(faceCount); // Resize an Array before copying some IDs
for (uint32_t f = 0; f < faceCount; f++) {
const uint32_t face = m_faceToSourceFaceMap[f];
for (uint32_t i = 0; i < 3; i++) {
Expand All @@ -7692,6 +7791,9 @@ class ChartGroup
mesh->addVertex(m_sourceMesh->position(vertex), normal, m_sourceMesh->texcoord(vertex));
}
}
// Add TriangleIDs and PolygonIDs
if (hasQuadsOrNGons)
mesh->trianglesToPolygonIDs[f] = m_sourceMesh->trianglesToPolygonIDs[m_faceToSourceFaceMap[f]];
}
// Add faces.
for (uint32_t f = 0; f < faceCount; f++) {
Expand Down Expand Up @@ -9099,24 +9201,27 @@ AddMeshError AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t meshCountH
internal::Array<uint32_t> triIndices;
internal::Array<uint32_t> indicesIDs;
internal::Triangulator triangulator;
uint32_t polygonStartID = 0;
uint32_t polygonVertexStartID = 0;
internal::Array<uint32_t> polygon;
bool hasQuadsOrNGons = false;
for (uint32_t face = 0; face < faceCount; face++) {
// Decode face indices.
const uint32_t faceVertexCount = meshDecl.faceVertexCount ? (uint32_t)meshDecl.faceVertexCount[face] : 3;
polygon.clear();
for (uint32_t i = 0; i < faceVertexCount; i++) {
if (hasIndices) {
uint32_t vertID = DecodeIndex(meshDecl.indexFormat, meshDecl.indexData, meshDecl.indexOffset, polygonStartID + i);
uint32_t vertID = DecodeIndex(meshDecl.indexFormat, meshDecl.indexData, meshDecl.indexOffset, polygonVertexStartID + i);
polygon.push_back(vertID);
if (faceVertexCount > 3) hasQuadsOrNGons = true; // Mesh has Quads or NGons.
// Check if any index is out of range.
if (polygon[i] >= meshDecl.vertexCount) {
if (polygon[i] >= meshDecl.vertexCount
|| faceVertexCount < 3) {
mesh->~Mesh();
XA_FREE(mesh);
return AddMeshError::IndexOutOfRange;
}
} else {
polygon[i] = polygonStartID + i;
polygon[i] = polygonVertexStartID + i;
}
}
// Ignore faces with degenerate or zero length edges.
Expand Down Expand Up @@ -9213,10 +9318,13 @@ AddMeshError AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t meshCountH
}
if (meshPolygonMapping) {
for (uint32_t i = 0; i < triIndices.size(); i++)
meshPolygonMapping->triangleToPolygonIndicesMap.push_back(indicesIDs[i] + polygonStartID);
meshPolygonMapping->triangleToPolygonIndicesMap.push_back(indicesIDs[i] + polygonVertexStartID);
}
polygonStartID += faceVertexCount; // Add an offset for the next polygon's start index
polygonVertexStartID += faceVertexCount; // Add an offset for the next polygon's start index
}
// Add TriangleIDs and PolygonIDs if we have Quads/NGons
if (meshPolygonMapping && hasQuadsOrNGons)
meshPolygonMapping->triangleToPolygonMap.copyTo(mesh->trianglesToPolygonIDs);
if (warningCount > kMaxWarnings)
XA_PRINT(" %u additional warnings truncated\n", warningCount - kMaxWarnings);
XA_PROFILE_END(addMeshCopyData)
Expand Down
2 changes: 2 additions & 0 deletions source/xatlas/xatlas.h
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Original file line number Diff line number Diff line change
Expand Up @@ -189,6 +189,8 @@ struct ChartOptions

bool useInputMeshUvs = false; // Use MeshDecl::vertexUvData for charts.
bool fixWinding = false; // Enforce consistent texture coordinate winding.

bool computeBoundaryIntersection = false; // Used in parameterize() to intersect edges. It can create artifacts (little peeces).
};

// Call after all AddMesh calls. Can be called multiple times to recompute charts with different options.
Expand Down
1 change: 1 addition & 0 deletions source/xatlas/xatlas_c.h
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Original file line number Diff line number Diff line change
Expand Up @@ -191,6 +191,7 @@ typedef struct
uint32_t maxIterations;
bool useInputMeshUvs;
bool fixWinding;
bool computeBoundaryIntersection;
}
xatlasChartOptions;

Expand Down

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