QGIS API Documentation  3.23.0-Master (eb871beae0)
qgsmesh3dsymbol_p.cpp
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1 /***************************************************************************
2  qgsmesh3dsymbol_p.cpp
3  ---------------------
4  Date : January 2019
5  Copyright : (C) 2019 by Peter Petrik
6  Email : zilolv at gmail dot com
7  ***************************************************************************
8  * *
9  * This program is free software; you can redistribute it and/or modify *
10  * it under the terms of the GNU General Public License as published by *
11  * the Free Software Foundation; either version 2 of the License, or *
12  * (at your option) any later version. *
13  * *
14  ***************************************************************************/
15 
16 #include "qgsmesh3dsymbol_p.h"
17 
18 #include "qgsmesh3dsymbol.h"
20 #include "qgs3dmapsettings.h"
21 #include "qgs3dutils.h"
22 
23 #include <Qt3DCore/QTransform>
24 #include <Qt3DRender/QEffect>
25 #include <Qt3DRender/QTechnique>
26 #include <Qt3DRender/QCullFace>
27 
28 #include "qgsmultipolygon.h"
29 #include "qgsmeshlayer.h"
30 #include "qgstriangularmesh.h"
33 
34 static QgsExpressionContext _expressionContext3D()
35 {
39  return ctx;
40 }
41 
43 
44 QgsMesh3DSymbolEntity::QgsMesh3DSymbolEntity( const Qgs3DMapSettings &map,
45  QgsMeshLayer *layer,
46  const QgsMesh3DSymbol &symbol,
47  Qt3DCore::QNode *parent )
48  : Qt3DCore::QEntity( parent )
49 {
50  // build the default material
51  Qt3DRender::QMaterial *mat = material( symbol );
52 
53  // build a transform function
54  Qt3DCore::QTransform *tform = new Qt3DCore::QTransform;
55  tform->setTranslation( QVector3D( 0, 0, 0 ) );
56 
57  // build the entity
58  QgsMesh3DSymbolEntityNode *entity = new QgsMesh3DSymbolEntityNode( map, layer, symbol );
59  entity->findChild<Qt3DRender::QGeometryRenderer *>()->setObjectName( QStringLiteral( "main" ) ); // temporary measure to distinguish between "selected" and "main"
60  entity->addComponent( mat );
61  entity->addComponent( tform );
62  entity->setParent( this );
63 }
64 
65 Qt3DRender::QMaterial *QgsMesh3DSymbolEntity::material( const QgsMesh3DSymbol &symbol ) const
66 {
67  const QgsMaterialContext context;
68  Qt3DRender::QMaterial *material = symbol.material()->toMaterial( QgsMaterialSettingsRenderingTechnique::Triangles, context );
69 
70  // front/back side culling
71  const auto techniques = material->effect()->techniques();
72  for ( auto tit = techniques.constBegin(); tit != techniques.constEnd(); ++tit )
73  {
74  auto renderPasses = ( *tit )->renderPasses();
75  for ( auto rpit = renderPasses.begin(); rpit != renderPasses.end(); ++rpit )
76  {
77  Qt3DRender::QCullFace *cullFace = new Qt3DRender::QCullFace;
78  cullFace->setMode( Qt3DRender::QCullFace::Back );
79  ( *rpit )->addRenderState( cullFace );
80  }
81  }
82  return material;
83 }
84 
85 QgsMesh3DSymbolEntityNode::QgsMesh3DSymbolEntityNode( const Qgs3DMapSettings &map,
86  QgsMeshLayer *layer,
87  const QgsMesh3DSymbol &symbol,
88  Qt3DCore::QNode *parent ) : Qt3DCore::QEntity( parent )
89 {
90  addComponent( renderer( map, symbol, layer ) );
91 }
92 
93 Qt3DRender::QGeometryRenderer *QgsMesh3DSymbolEntityNode::renderer( const Qgs3DMapSettings &map,
94  const QgsMesh3DSymbol &symbol,
95  const QgsMeshLayer *layer )
96 {
97  const QgsPointXY origin( map.origin().x(), map.origin().y() );
98  QList<QgsPolygon *> polygons;
99  QList<QgsFeatureId> fids;
100 
101  const QgsExpressionContext ctx( _expressionContext3D() );
102  const QgsPropertyCollection &ddp = symbol.dataDefinedProperties();
103  const bool hasDDHeight = ddp.isActive( QgsAbstract3DSymbol::PropertyHeight );
104  float height = symbol.height();
105  if ( hasDDHeight )
106  {
107  height = static_cast<float>( ddp.valueAsDouble( QgsAbstract3DSymbol::PropertyHeight,
108  ctx,
109  static_cast<double>( height )
110  )
111  );
112  }
113 
114  const QgsTriangularMesh *mesh = layer->triangularMesh();
115  if ( mesh )
116  {
117  const QVector<QgsMeshFace> &triangles = mesh->triangles();
118  const QVector<QgsMeshVertex> &vertices = mesh->vertices();
119  for ( int i = 0; i < triangles.size(); ++i )
120  {
121  const QgsMeshFace &triangle = triangles.at( i );
122  Q_ASSERT( triangle.size() == 3 );
123  std::unique_ptr< QgsPolygon > polygon = QgsMeshUtils::toPolygon( triangle, vertices );
124  Qgs3DUtils::clampAltitudes( polygon.get(),
125  symbol.altitudeClamping(),
126  Qgs3DTypes::AltitudeBinding::AltBindVertex,
127  height,
128  map );
129  polygons.append( polygon.release() );
130  fids.append( i );
131  }
132  }
133 
134  // Polygons from mesh are already triangles, but
135  // call QgsTessellatedPolygonGeometry to
136  // use symbol settings for back faces, normals, etc
137 
138  const QgsPhongTexturedMaterialSettings *texturedMaterialSettings = dynamic_cast< const QgsPhongTexturedMaterialSettings * >( symbol.material() );
139 
140  mGeometry = new QgsTessellatedPolygonGeometry( true, false, symbol.addBackFaces(), texturedMaterialSettings ? texturedMaterialSettings->requiresTextureCoordinates() : false );
141  const QList<float> extrusionHeightPerPolygon;
142  mGeometry->setPolygons( polygons, fids, origin, 0.0, extrusionHeightPerPolygon );
143 
144  Qt3DRender::QGeometryRenderer *renderer = new Qt3DRender::QGeometryRenderer;
145  renderer->setGeometry( mGeometry );
146 
147  return renderer;
148 }
QgsVector3D origin() const
Returns coordinates in map CRS at which 3D scene has origin (0,0,0)
static void clampAltitudes(QgsLineString *lineString, Qgs3DTypes::AltitudeClamping altClamp, Qgs3DTypes::AltitudeBinding altBind, const QgsPoint &centroid, float height, const Qgs3DMapSettings &map)
Clamps altitude of vertices of a linestring according to the settings.
Definition: qgs3dutils.cpp:270
QgsPropertyCollection & dataDefinedProperties()
Returns a reference to the symbol layer's property collection, used for data defined overrides.
@ PropertyHeight
Height (altitude)
virtual Qt3DRender::QMaterial * toMaterial(QgsMaterialSettingsRenderingTechnique technique, const QgsMaterialContext &context) const =0
Creates a new QMaterial object representing the material settings.
double valueAsDouble(int key, const QgsExpressionContext &context, double defaultValue=0.0, bool *ok=nullptr) const
Calculates the current value of the property with the specified key and interprets it as a double.
static QgsExpressionContextScope * projectScope(const QgsProject *project)
Creates a new scope which contains variables and functions relating to a QGIS project.
static QgsExpressionContextScope * globalScope()
Creates a new scope which contains variables and functions relating to the global QGIS context.
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
QgsAbstractMaterialSettings * material() const
Returns material used for shading of the symbol.
bool addBackFaces() const
Returns whether also triangles facing the other side will be created.
float height() const
Returns height (altitude) of the symbol (in map units)
Qgs3DTypes::AltitudeClamping altitudeClamping() const
Returns method that determines altitude (whether to clamp to feature to terrain)
Represents a mesh layer supporting display of data on structured or unstructured meshes.
Definition: qgsmeshlayer.h:97
QgsTriangularMesh * triangularMesh(double minimumTriangleSize=0) const
Returns triangular mesh (nullptr before rendering or calling to updateMesh).
bool requiresTextureCoordinates() const
Returns true if the material requires texture coordinates to be generated during triangulation....
A class to represent a 2D point.
Definition: qgspointxy.h:59
static QgsProject * instance()
Returns the QgsProject singleton instance.
Definition: qgsproject.cpp:468
A grouped map of multiple QgsProperty objects, each referenced by a integer key value.
bool isActive(int key) const override
Returns true if the collection contains an active property with the specified key.
Triangular/Derived Mesh is mesh with vertices in map coordinates.
const QVector< QgsMeshFace > & triangles() const
Returns triangles.
const QVector< QgsMeshVertex > & vertices() const
Returns vertices in map coordinate system.
double y() const
Returns Y coordinate.
Definition: qgsvector3d.h:51
double x() const
Returns X coordinate.
Definition: qgsvector3d.h:49
@ Triangles
Triangle based rendering (default)
CORE_EXPORT std::unique_ptr< QgsPolygon > toPolygon(const QgsMeshFace &face, const QVector< QgsMeshVertex > &vertices)
Returns face as polygon geometry, caller is responsible for delete.
QVector< int > QgsMeshFace
List of vertex indexes.