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// Copyright (C) 2017 The Qt Company Ltd and/or its subsidiary(-ies).
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "objgeometryloader.h"
#include <QtCore/QHash>
#include <QtCore/QLoggingCategory>
#include <QtCore/QRegularExpression>
#include <QtCore/QIODevice>
QT_BEGIN_NAMESPACE
namespace Qt3DRender {
Q_LOGGING_CATEGORY(ObjGeometryLoaderLog, "Qt3D.ObjGeometryLoader", QtWarningMsg)
static void addFaceVertex(const FaceIndices &faceIndices,
QList<FaceIndices> &faceIndexVector,
QHash<FaceIndices, unsigned int> &faceIndexMap);
inline uint qHash(const FaceIndices &faceIndices)
{
return faceIndices.positionIndex
+ 10 * faceIndices.texCoordIndex
+ 100 * faceIndices.normalIndex;
}
bool ObjGeometryLoader::doLoad(QIODevice *ioDev, const QString &subMesh)
{
// Parse faces taking into account each vertex in a face can index different indices
// for the positions, normals and texture coords;
// Generate unique vertices (in OpenGL parlance) and output to points, texCoords,
// normals and calculate mapping from faces to unique indices
QList<QVector3D> positions;
QList<QVector3D> normals;
QList<QVector2D> texCoords;
QHash<FaceIndices, unsigned int> faceIndexMap;
QList<FaceIndices> faceIndexVector;
bool skipping = false;
int positionsOffset = 0;
int normalsOffset = 0;
int texCoordsOffset = 0;
QRegularExpression subMeshMatch(subMesh);
if (!subMeshMatch.isValid())
subMeshMatch.setPattern(QLatin1String("^(") + subMesh + QLatin1String(")$"));
Q_ASSERT(subMeshMatch.isValid());
char lineBuffer[1024];
const char *line;
QByteArray longLine;
while (!ioDev->atEnd()) {
// try to read into lineBuffer first, if the line fits (common case) we can do this without expensive allocations
// if not, fall back to dynamically allocated QByteArrays
auto lineSize = ioDev->readLine(lineBuffer, sizeof(lineBuffer));
if (lineSize == sizeof(lineBuffer) - 1 && lineBuffer[lineSize - 1] != '\n') {
longLine = QByteArray(lineBuffer, lineSize);
longLine += ioDev->readLine();
line = longLine.constData();
lineSize = longLine.size();
} else {
line = lineBuffer;
}
if (lineSize > 0 && line[0] != '#') {
if (line[lineSize - 1] == '\n')
--lineSize; // chop newline
if (lineSize <= 0)
continue;
if (line[lineSize - 1] == '\r')
--lineSize; // chop newline also for CRLF format
if (lineSize <= 0)
continue;
while (lineSize > 0 && (line[lineSize - 1] == ' ' || line[lineSize - 1] == '\t')) {
--lineSize; // chop trailing spaces
}
if (lineSize <= 0)
continue;
const ByteArraySplitter tokens(line, line + lineSize, ' ', Qt::SkipEmptyParts);
if (qstrncmp(tokens.charPtrAt(0), "v ", 2) == 0) {
if (tokens.size() < 4) {
qCWarning(ObjGeometryLoaderLog) << "Unsupported number of components in vertex";
} else {
if (!skipping) {
const float x = tokens.floatAt(1);
const float y = tokens.floatAt(2);
const float z = tokens.floatAt(3);
positions.append(QVector3D(x, y, z));
} else {
positionsOffset++;
}
}
} else if (m_loadTextureCoords && qstrncmp(tokens.charPtrAt(0), "vt ", 3) == 0) {
if (tokens.size() < 3) {
qCWarning(ObjGeometryLoaderLog) << "Unsupported number of components in texture coordinate";
} else {
if (!skipping) {
// Process texture coordinate
const float s = tokens.floatAt(1);
const float t = tokens.floatAt(2);
texCoords.append(QVector2D(s, t));
} else {
++texCoordsOffset;
}
}
} else if (qstrncmp(tokens.charPtrAt(0), "vn ", 3) == 0) {
if (tokens.size() < 4) {
qCWarning(ObjGeometryLoaderLog) << "Unsupported number of components in vertex normal";
} else {
if (!skipping) {
const float x = tokens.floatAt(1);
const float y = tokens.floatAt(2);
const float z = tokens.floatAt(3);
normals.append(QVector3D(x, y, z));
} else {
++normalsOffset;
}
}
} else if (!skipping && tokens.size() >= 4 && qstrncmp(tokens.charPtrAt(0), "f ", 2) == 0) {
// Process face
int faceVertices = tokens.size() - 1;
QVarLengthArray<FaceIndices, 4> face; // try to avoid allocations in the common case of triangulated data
face.reserve(faceVertices);
for (int i = 0; i < faceVertices; i++) {
FaceIndices faceIndices;
const ByteArraySplitter indices = tokens.splitterAt(i + 1, '/', Qt::KeepEmptyParts);
switch (indices.size()) {
case 3:
faceIndices.normalIndex = indices.intAt(2) - 1 - normalsOffset; // fall through
Q_FALLTHROUGH();
case 2:
faceIndices.texCoordIndex = indices.intAt(1) - 1 - texCoordsOffset; // fall through
Q_FALLTHROUGH();
case 1:
faceIndices.positionIndex = indices.intAt(0) - 1 - positionsOffset;
break;
default:
qCWarning(ObjGeometryLoaderLog) << "Unsupported number of indices in face element";
}
face.append(faceIndices);
}
// If number of edges in face is greater than 3,
// decompose into triangles as a triangle fan.
FaceIndices v0 = face[0];
FaceIndices v1 = face[1];
FaceIndices v2 = face[2];
// First face
addFaceVertex(v0, faceIndexVector, faceIndexMap);
addFaceVertex(v1, faceIndexVector, faceIndexMap);
addFaceVertex(v2, faceIndexVector, faceIndexMap);
for (int i = 3; i < face.size(); ++i) {
v1 = v2;
v2 = face[i];
addFaceVertex(v0, faceIndexVector, faceIndexMap);
addFaceVertex(v1, faceIndexVector, faceIndexMap);
addFaceVertex(v2, faceIndexVector, faceIndexMap);
}
// end of face
} else if (qstrncmp(tokens.charPtrAt(0), "o ", 2) == 0) {
if (tokens.size() < 2) {
qCWarning(ObjGeometryLoaderLog) << "Missing submesh name";
} else {
if (!subMesh.isEmpty() ) {
const QString objName = tokens.stringAt(1);
QRegularExpressionMatch match = subMeshMatch.match(objName);
skipping = !match.hasMatch();
}
}
}
} // empty input line
} // while (!ioDev->atEnd())
// Iterate over the faceIndexMap and pull out pos, texCoord and normal data
// thereby generating unique vertices of data (by OpenGL definition)
const qsizetype vertexCount = faceIndexMap.size();
const bool hasTexCoords = !texCoords.isEmpty();
const bool hasNormals = !normals.isEmpty();
m_points.resize(vertexCount);
m_texCoords.clear();
if (hasTexCoords)
m_texCoords.resize(vertexCount);
m_normals.clear();
if (hasNormals)
m_normals.resize(vertexCount);
for (auto it = faceIndexMap.cbegin(), endIt = faceIndexMap.cend(); it != endIt; ++it) {
const uint positionIndex = it.key().positionIndex;
const uint texCoordIndex = it.key().texCoordIndex;
const uint normalIndex = it.key().normalIndex;
m_points[it.value()] = (positionIndex < uint(positions.size())) ? positions[positionIndex] : QVector3D();
if (hasTexCoords)
m_texCoords[it.value()] = (texCoordIndex < uint(texCoords.size())) ? texCoords[texCoordIndex] : QVector2D();
if (hasNormals)
m_normals[it.value()] = (normalIndex < uint(normals.size())) ? normals[normalIndex] : QVector3D();
}
// Now iterate over the face indices and lookup the unique vertex index
const qsizetype indexCount = faceIndexVector.size();
m_indices.clear();
m_indices.reserve(indexCount);
for (const FaceIndices &faceIndices : std::as_const(faceIndexVector)) {
const unsigned int i = faceIndexMap.value(faceIndices);
m_indices.push_back(i);
}
return true;
}
static void addFaceVertex(const FaceIndices &faceIndices,
QList<FaceIndices> &faceIndexVector,
QHash<FaceIndices, unsigned int> &faceIndexMap)
{
if (faceIndices.positionIndex != std::numeric_limits<unsigned int>::max()) {
faceIndexVector.append(faceIndices);
if (!faceIndexMap.contains(faceIndices))
faceIndexMap.insert(faceIndices, faceIndexMap.size());
} else {
qCWarning(ObjGeometryLoaderLog) << "Missing position index";
}
}
} // namespace Qt3DRender
QT_END_NAMESPACE
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