3D surface plot item with VBO/VAO rendering More...

#include <qwt3d_surface.h>

Inheritance diagram for Qwt3DSurface:

Classes
class	PrivateData

Public Member Functions
	Qwt3DSurface ()
	Constructs an empty surface item.

	~Qwt3DSurface () override
	Destructor — releases GL resources and data.

void	loadFromData (Triple **data, unsigned int columns, unsigned int rows, bool uperiodic=false, bool vperiodic=false)
	Load grid data from Triple array (x, y, z per vertex)

void	loadFromData (double **data, unsigned int columns, unsigned int rows, double minx, double maxx, double miny, double maxy)
	Load grid data from z-value matrix with explicit x/y domain.

void	loadFromData (const Qwt3DFunctionData &data)
	Load grid data from a Qwt3DFunctionData result (modern vector API)

void	loadFromData (const Qwt3DParametricData &data)
	Load grid data from a Qwt3DParametricData result (modern vector API)

void	loadFromData (TripleField const &nodes, CellField const &poly)
	Load cell (polygon) data from node coordinates and cell indices.

int	resolution () const
	Returns data resolution (1 = all data, higher = coarser)

FLOORSTYLE	floorStyle () const
	Returns the current floor projection style.

void	setFloorStyle (FLOORSTYLE style)
	Sets the floor projection style.

bool	normals () const
	Returns true if normal vectors are drawn.

void	showNormals (bool b)
	Show or hide normal vectors at each vertex.

double	normalLength () const
	Returns the relative length of drawn normals (0..1)

void	setNormalLength (double val)
	Sets the relative length of drawn normals.

int	normalQuality () const
	Returns the quality of normal arrow rendering.

void	setNormalQuality (int val)
	Sets the quality of normal arrow rendering (minimum 3)

std::pair< int, int >	facets () const
	Returns the number of mesh cells in the original data.

void	updateNormals ()
	Recalculates surface normals from current data.

PLOTSTYLE	plotStyle () const
	Returns the current plotting style.

void	setPlotStyle (PLOTSTYLE style)
	Sets the plotting style.

void	setDataColor (Qwt3DColor *color)
	Sets the data color functor (takes ownership)

const Qwt3DColor *	dataColor () const
	Returns the data color functor.

void	invalidateColors ()
	Marks per-vertex colors as stale, triggering a VBO rebuild on the next draw.

RGBA	meshColor () const
	Returns the mesh line color.

void	setMeshColor (RGBA color)
	Sets the mesh line color.

double	meshLineWidth () const
	Returns the mesh line width.

void	setMeshLineWidth (double width)
	Sets the mesh line width.

int	isolines () const
	Returns the number of isolines.

void	setIsolines (int n)
	Sets the number of isolines.

bool	smoothMesh () const
	Returns true if smooth mesh lines are enabled.

void	setSmoothMesh (bool smooth)
	Enables or disables smooth mesh lines.

double	polygonOffset () const
	Returns the polygon offset for filled rendering.

void	setPolygonOffset (double offset)
	Sets the polygon offset for filled rendering.

SHADINGSTYLE	shading () const
	Returns the shading style.

void	setShading (SHADINGSTYLE style)
	Sets the shading style.

Qwt3DEnrichment *	addEnrichment (Qwt3DEnrichment const &enrichment)
	Adds an enrichment to the surface (clones the argument)

bool	degrade (Qwt3DEnrichment *enrichment)
	Removes an enrichment from the surface.

int	rtti () const override
	运行时类型信息

void	draw () override
	Draws the surface using VBO/VAO and GLSL shaders.

ParallelEpiped	hull () const override
	Returns the bounding hull of the surface in 3D space.

void	populateLegendColors (ColorVector &colors) const override
	Populate the legend color vector from the item's color functor.

Qwt3DGridData *	gridData () const
	Returns the grid data pointer (nullptr if cell data)

Qwt3DCellData *	cellData () const
	Returns the cell data pointer (nullptr if grid data)

bool	isGridData () const
	Returns true if the current data is grid-based.

void	setResolution (int res)
	Sets the data resolution (1 = full, higher = coarser)

Public Member Functions inherited from Qwt3DPlotItem
	Qwt3DPlotItem ()
	Default constructor.

virtual	~Qwt3DPlotItem ()
	Destructor — detaches from any plot.

void	attach (Qwt3DPlot *plot)
	Attach the item to a plot.

void	detach ()
	Detach the item from its plot.

Qwt3DPlot *	plot () const
	Get the plot this item is attached to.

void	setTitle (const QString &title)
	Set the item title.

QString	title () const
	Get the item title.

void	setZ (double z)
	Set the z-order value (controls draw sequence)

double	z () const
	Get the z-order value.

void	setVisible (bool on)
	Set item visibility.

bool	isVisible () const
	Check if the item is visible.

virtual void	itemChanged ()
	Notify the plot that the item has changed.

Detailed Description

3D surface plot item with VBO/VAO rendering

Qwt3DSurface is a Qwt3DPlotItem that renders 3D surface data using modern OpenGL (VBO/VAO + GLSL shaders). It supports both grid-based (regular mesh) and cell-based (polygon mesh) data, with multiple rendering styles (filled, wireframe, hiddenline, points).

The item manages its own data storage, color mapping, and GL resources (VBO, VAO, EBO, shader program). Data is uploaded to GPU memory when dirty and reused across frames until the data changes.

auto plot = new Qwt3DPlot(parent);
 
auto surface = new Qwt3DSurface();
surface->loadFromData(data, columns, rows, minX, maxX, minY, maxY);
surface->setPlotStyle(FILLEDMESH);
surface->attach(plot);

See also: Qwt3DPlotItem, Qwt3DPlot, Qwt3DColor

Constructor & Destructor Documentation

◆ Qwt3DSurface()

Qwt3DSurface::Qwt3DSurface ( )

Constructs an empty surface item.

Constructs an empty Qwt3DSurface item.

Initializes data storage (empty grid and cell data) and GL resource placeholders. VBO/VAO/shader are created lazily in draw().

Destructor

GL resources (VBO, EBO, VAO) are cleaned up in PrivateData destructor. Data pointers and color functor are also deleted there.

Load grid data from Triple array

Parameters

data	2D array of Triple values [columns][rows]
columns	Number of columns in the grid
rows	Number of rows in the grid
uperiodic	Whether the u-direction is periodic
vperiodic	Whether the v-direction is periodic

Reads vertex positions, computes normals, and marks the VBO for rebuild.

Member Function Documentation

◆ addEnrichment()

Qwt3DEnrichment * Qwt3DSurface::addEnrichment ( Qwt3DEnrichment const & enrichment )

Adds an enrichment to the surface (clones the argument)

Adds an enrichment to the surface.

Parameters

enrichment The enrichment to add (will be cloned)

Returns: Pointer to the cloned enrichment, or nullptr if type is not VERTEXENRICHMENT

The enrichment is cloned and assigned to the current plot. TODO: Enrichment rendering with VBO will be implemented in a future plan.

◆ cellData()

Qwt3DCellData * Qwt3DSurface::cellData ( ) const

Returns the cell data pointer (nullptr if grid data)

Returns the cell data pointer.

Returns: Pointer to Qwt3DCellData, or nullptr if current data is grid-based

◆ degrade()

bool Qwt3DSurface::degrade ( Qwt3DEnrichment * enrichment )

Removes an enrichment from the surface.

Parameters

enrichment Pointer to the enrichment to remove

Returns: true if the enrichment was found and removed

◆ draw()

void Qwt3DSurface::draw ( )

overridevirtual

Draws the surface using VBO/VAO and GLSL shaders.

Called by Qwt3DPlot::paintGL() for each visible item. The GL context is guaranteed to be current.

Rendering strategy by plot style:

FILLED: glDrawElements(GL_TRIANGLES) with vertex colors
FILLEDMESH: triangles + lines (two draw calls)
WIREFRAME: glDrawElements(GL_LINES) with mesh color
HIDDENLINE: triangles with background color + lines
QWT3D_POINTS: glDrawArrays(GL_POINTS)

Implements Qwt3DPlotItem.

◆ facets()

std::pair< int, int > Qwt3DSurface::facets ( ) const

Returns the number of mesh cells in the original data.

Returns: For grid data: (columns, rows). For cell data: (cells, 0).

◆ floorStyle()

FLOORSTYLE Qwt3DSurface::floorStyle ( ) const

Returns the current floor projection style.

Returns the floor projection style.

◆ gridData()

Qwt3DGridData * Qwt3DSurface::gridData ( ) const

Returns the grid data pointer (nullptr if cell data)

Returns the grid data pointer.

Returns: Pointer to Qwt3DGridData, or nullptr if current data is cell-based

◆ hull()

ParallelEpiped Qwt3DSurface::hull ( ) const

overridevirtual

Returns the bounding hull of the surface in 3D space.

Returns: ParallelEpiped bounding the surface data, or a degenerate box if no data

Implements Qwt3DPlotItem.

◆ invalidateColors()

void Qwt3DSurface::invalidateColors ( )

Marks per-vertex colors as stale, triggering a VBO rebuild on the next draw.

Marks per-vertex colors as stale.

Per-vertex colors are baked into the VBO during buildVBO(). Mutating the color functor in place (e.g. setColorMap, setAlpha) does not automatically trigger a rebuild. Call this method afterwards so that draw() re-runs the color functor and re-uploads the vertex buffer.

◆ loadFromData() [1/4]

void Qwt3DSurface::loadFromData ( const Qwt3DFunctionData & data )

Load grid data from a Qwt3DFunctionData result (modern vector API)

Load grid data from a Qwt3DFunctionData result.

Parameters

data	Result of Qwt3DFunction::create() containing z-values and domain

Converts the vector-based data to the internal grid format and delegates to the pointer-based overload. Memory-safe: the vector data is read-only; a temporary pointer array is created for the legacy API.

◆ loadFromData() [2/4]

void Qwt3DSurface::loadFromData ( const Qwt3DParametricData & data )

Load grid data from a Qwt3DParametricData result (modern vector API)

Load grid data from a Qwt3DParametricData result.

Parameters

data	Result of Qwt3DParametricSurface::create() containing xyz triples

Converts the vector-based data to the internal grid format and delegates to the pointer-based overload. Memory-safe: the vector data is read-only; a temporary pointer array is created for the legacy API.

◆ loadFromData() [3/4]

void Qwt3DSurface::loadFromData	(	double **	data,
		unsigned int	columns,
		unsigned int	rows,
		double	minx,
		double	maxx,
		double	miny,
		double	maxy
	)

Load grid data from z-value matrix with explicit x/y domain.

Load grid data from z-value matrix.

Parameters

data	2D array of z-values [columns][rows]
columns	Number of columns in the grid
rows	Number of rows in the grid
minx	Minimum x coordinate
maxx	Maximum x coordinate
miny	Minimum y coordinate
maxy	Maximum y coordinate

Generates x/y coordinates from the domain, reads z-values, computes normals, and marks the VBO for rebuild.

◆ loadFromData() [4/4]

void Qwt3DSurface::loadFromData	(	TripleField const &	nodes,
		CellField const &	poly
	)

Load cell (polygon) data from node coordinates and cell indices.

Parameters

nodes	Vector of 3D node coordinates
poly	Vector of cells (each cell is a vector of node indices)

Stores node positions and cell topology, computes per-vertex normals and bounding hull, and marks the VBO for rebuild.

◆ populateLegendColors()

void Qwt3DSurface::populateLegendColors ( ColorVector & colors ) const

overridevirtual

Populate the legend color vector from the item's color functor.

Reimplemented from Qwt3DPlotItem.

◆ resolution()

int Qwt3DSurface::resolution ( ) const

Returns data resolution (1 = all data, higher = coarser)

Returns the current data resolution.

Returns: Resolution value (1 = full data, higher = coarser)

◆ rtti()

int Qwt3DSurface::rtti ( ) const

overridevirtual

运行时类型信息

Returns: Rtti_Plot3DSurface (= 1001)

Reimplemented from Qwt3DPlotItem.

◆ setDataColor()

void Qwt3DSurface::setDataColor ( Qwt3DColor * color )

Sets the data color functor (takes ownership)

Sets the data color functor.

Parameters

color Pointer to a Qwt3DColor subclass (item takes ownership)

The color functor is called per-vertex during VBO build to compute vertex colors. If nullptr, a default Qwt3DStandardColor is created lazily when the item is attached to a plot.

◆ setFloorStyle()

void Qwt3DSurface::setFloorStyle ( FLOORSTYLE style )

Sets the floor projection style.

Parameters

style Floor projection style

TODO: Floor projection rendering will be implemented as a separate Qwt3DFloorProjection item in a future plan.

◆ setNormalLength()

void Qwt3DSurface::setNormalLength ( double val )

Sets the relative length of drawn normals.

Parameters

val	Relative length (0..1, relative to hull diagonal)

◆ setNormalQuality()

void Qwt3DSurface::setNormalQuality ( int val )

Sets the quality of normal arrow rendering (minimum 3)

Sets the quality of normal arrow rendering.

Parameters

val	Quality value (minimum 3)

◆ setPlotStyle()

void Qwt3DSurface::setPlotStyle ( PLOTSTYLE style )

Sets the plotting style.

Parameters

style One of NOPLOT, WIREFRAME, HIDDENLINE, FILLED, FILLEDMESH, QWT3D_POINTS

◆ setResolution()

void Qwt3DSurface::setResolution ( int res )

Sets the data resolution (1 = full, higher = coarser)

Sets the data resolution.

Parameters

res	Resolution value (1 = full data, higher = coarser)

Resolution controls index buffer stepping: higher values skip vertices in the index buffer, reducing rendered detail without rebuilding the VBO. A value of 1 renders all data.

◆ setShading()

void Qwt3DSurface::setShading ( SHADINGSTYLE style )

Sets the shading style.

Parameters

style One of GOURAUD, FLAT, or SMOOTH

The shading style controls per-fragment lighting interpolation. Currently stored for shader uniform use; full implementation requires shader-level branching.

◆ updateNormals()

void Qwt3DSurface::updateNormals ( )

Recalculates surface normals from current data.

For grid data, recalculates normals using 4-neighbor cross products. For cell data, recalculates normals from cell topology. Marks the VBO for rebuild.

The documentation for this class was generated from the following files:

/home/runner/work/QWT/QWT/src/plot3d/qwt3d_surface.h
/home/runner/work/QWT/QWT/src/plot3d/qwt3d_surface.cpp

Classes

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Qwt3DSurface()

Member Function Documentation

◆ addEnrichment()

◆ cellData()

◆ degrade()

◆ draw()

◆ facets()

◆ floorStyle()

◆ gridData()

◆ hull()

◆ invalidateColors()

◆ loadFromData() [1/4]

◆ loadFromData() [2/4]

◆ loadFromData() [3/4]

◆ loadFromData() [4/4]

◆ populateLegendColors()

◆ resolution()

◆ rtti()

◆ setDataColor()

◆ setFloorStyle()

◆ setNormalLength()

◆ setNormalQuality()

◆ setPlotStyle()

◆ setResolution()

◆ setShading()

◆ updateNormals()