SoQtGLWidget - Man Page

The SoQtGLWidget class manages OpenGL contexts.

Synopsis

#include <Inventor/Qt/SoQtGLWidget.h>

Inherits SoQtComponent.

Inherited by SoQtRenderArea.

Public Member Functions

void setBorder (const SbBool enable)
SbBool isBorder (void) const
virtual void setDoubleBuffer (const SbBool enable)
SbBool isDoubleBuffer (void) const
void setDrawToFrontBufferEnable (const SbBool enable)
SbBool isDrawToFrontBufferEnable (void) const
void setQuadBufferStereo (const SbBool enable)
SbBool isQuadBufferStereo (void) const
void setAccumulationBuffer (const SbBool enable)
SbBool getAccumulationBuffer (void) const
void setStencilBuffer (const SbBool enable)
SbBool getStencilBuffer (void) const
void setAlphaChannel (const SbBool enable)
SbBool getAlphaChannel (void) const
void setOverlayRender (const SbBool onoff)
SbBool isOverlayRender (void) const
void setSampleBuffers (const int numsamples)
int getSampleBuffers (void) const
void setStealFocus (SbBool enable)
SbBool isStealFocus (void) const
QWidget * getGLWidget (void) const
QWidget * getNormalWidget (void) const
QWidget * getOverlayWidget (void) const
SbBool hasOverlayGLArea (void) const
SbBool hasNormalGLArea (void) const
unsigned long getOverlayTransparentPixel (void)
void getPointSizeLimits (SbVec2f &range, float &granularity)
void getLineWidthLimits (SbVec2f &range, float &granularity)

Protected Member Functions

SoQtGLWidget (QWidget *const parent=NULL, const char *const name=NULL, const SbBool embed=TRUE, const int glmodes=SO_GL_RGB, const SbBool build=TRUE)
~SoQtGLWidget ()
virtual void processEvent (QEvent *event)
QWidget * buildWidget (QWidget *parent)
virtual void redraw (void)=0
virtual void redrawOverlay (void)
virtual void initGraphic (void)
virtual void initOverlayGraphic (void)
virtual void sizeChanged (const SbVec2s &size)
virtual void widgetChanged (QWidget *w)
void setGLSize (const SbVec2s size)
SbVec2s getGLSize (void) const
float getGLAspectRatio (void) const
void setGlxSize (const SbVec2s size)
SbVec2s getGlxSize (void) const
float getGlxAspectRatio (void) const
void setStereoBuffer (SbBool flag)
SbBool isStereoBuffer (void) const
SbBool isRGBMode (void)
void glLockNormal (void)
void glUnlockNormal (void)
void glLockOverlay (void)
void glUnlockOverlay (void)
void glSwapBuffers (void)
void glFlushBuffer (void)
virtual SbBool glScheduleRedraw (void)

Protected Attributes

SbBool waitForExpose
SbBool drawToFrontBuffer

Additional Inherited Members

Detailed Description

The SoQtGLWidget class manages OpenGL contexts.

This is the basic, abstract component class which sets up an OpenGL canvas for its subclasses.

Application programmers will normally not use this class directly, but rather through the interface of either its direct descendent, SoQtRenderArea, or through one of the 'rapid application development'-style viewer subclasses.

An important thing to know about embedding SoQtGLWidget derived components into other Qt widgets is that you need to set up 'focus proxying' to have events still be sent to the OpenGL canvas widget. This is true for both the SoQtRenderArea as well as all the viewer components (like SoQtExaminerViewer, SoQtPlaneViewer etc).

As an example, if you embed an SoQtExaminerViewer inside a QFrame like this:

QMainWindow * toplevel = new QMainWindow;
QFrame * frame = new QFrame(toplevel);
SoQtExaminerViewer * viewer = new SoQtExaminerViewer(toplevel);

...events from the keyboard will not always automatically be forwarded to the viewer OpenGL canvas. This is the code you need to add in this case:

toplevel->setFocusProxy(viewer->getWidget());

Constructor & Destructor Documentation

SoQtGLWidget::SoQtGLWidget (QWidget *const parent = NULL, const char *const name = NULL, const SbBool embed = TRUE, const int glmodes = SO_GL_RGB, const SbBool build = TRUE) [protected]

The constructor is protected, as this is an abstract class to only be used by its subclasses.

SoQtGLWidget::~SoQtGLWidget () [protected]

Clean up all use of internal resources.

The destructor is protected, as this is an abstract class to only be used by its subclasses.

Member Function Documentation

void SoQtGLWidget::setBorder (const SbBool enable)

Specify whether or not there should be a border framing the OpenGL canvas. The border will be 2 pixels wide.

The default is to display the OpenGL canvas with no border.

See also

isBorder()

SbBool SoQtGLWidget::isBorder (void) const

Returns whether or not there's a border framing the OpenGL canvas.

See also

setBorder()

void SoQtGLWidget::setDoubleBuffer (const SbBool enable) [virtual]

Switch between single and double buffer mode for the OpenGL canvas. The default is to use a single buffer canvas.

See also

isDoubleBuffer()

Reimplemented in SoQtViewer.

SbBool SoQtGLWidget::isDoubleBuffer (void) const

Returns the status of the buffer mode.

See also

setDoubleBuffer()

void SoQtGLWidget::setDrawToFrontBufferEnable (const SbBool enable)

If this is set to TRUE, rendering will happen in the front buffer even if the current rendering mode is double buffered.

SbBool SoQtGLWidget::isDrawToFrontBufferEnable (void) const

See also

setDrawToFrontBufferEnable()

void SoQtGLWidget::setQuadBufferStereo (const SbBool enable)

Enables or disables OpenGL quad buffer stereo.

SbBool SoQtGLWidget::isQuadBufferStereo (void) const

Returns TRUE if quad buffer stereo is enabled for this widget.

void SoQtGLWidget::setAccumulationBuffer (const SbBool enable)

Enables/disables the OpenGL accumulation buffer.

For general information about accumulation buffers, confer with your OpenGL reference documentation.

By default, the accumulation buffer will be attempted disabled. Whether or not it will actually be disabled depends on what OpenGL contexts are available on the system. It is perfectly possible that the only usable contexts with regard to the other settings (like double buffering and RGBA mode versus color index mode) causes the context selection to choose an OpenGL format that contains an accumulation buffer, even though it was not requested.

Vice versa, one is not guaranteed to get accumulation buffers even when requested through this function, either because they are not available, or because they are only available in combination with other OpenGL context settings that are not wanted (like single buffers, non-accelerated rendering, etc).

If you try to enable accumulation buffers by using this function, you should therefore in succession use the SoQtGLWidget::getAccumulationBuffer() to query whether or not an accumulation buffer could actually be set up.

See also

SoQtRenderArea::setAntiAliasing()

SbBool SoQtGLWidget::getAccumulationBuffer (void) const

Returns whether the OpenGL accumulation buffer is enabled.

The returned flag will indicate whether or not accumulation buffers are actually present, and not just parrot the input value to SoQtGLWidget::setAccumulationBuffer(). See documentation of that function for more information.

void SoQtGLWidget::setStencilBuffer (const SbBool enable)

Enables/disables the OpenGL stencil buffer.

For general information about stencil buffers, confer with your OpenGL reference documentation.

By default, the stencil buffer will be attempted disabled, but the same notes apply for stencil buffers as for accumulation buffers. For an explanation on the issue of stencil and accumulation buffer availability, see the function documentation of SoQtGLWidget::setAccumulationBuffer().

SbBool SoQtGLWidget::getStencilBuffer (void) const

Returns whether the OpenGL stencil buffer is enabled.

The returned flag will indicate whether or not stencil buffers are actually present, in the same manner as for SoQtGLWidget::getAccumulationBuffer(). See documentation of SoQtGLWidget::setStencilBuffer().

void SoQtGLWidget::setAlphaChannel (const SbBool enable)

Enables/disables the alpha channel for the OpenGL context.

SbBool SoQtGLWidget::getAlphaChannel (void) const

Returns whether the alpha channel is enabled for the OpenGL context.

void SoQtGLWidget::setOverlayRender (const SbBool onoff)

Turn on or off the use of overlay planes.

See also

isOverlayRender()

SbBool SoQtGLWidget::isOverlayRender (void) const

Returns a flag indicating whether or not overplay planes are currently used.

See also

setOverlayRender()

void SoQtGLWidget::setSampleBuffers (const int numsamples)

Set the number of samples use when enabling multisample buffer contexts. Multisampling will be enabled when numsamples > 1.

int SoQtGLWidget::getSampleBuffers (void) const

Returns the number of samples used for multisampling. Returns 1 if multisampling is disabled.

void SoQtGLWidget::setStealFocus (SbBool enable)

Sets whether the GL widget should steal keyboard focus when the mouse is over the GL view.

Default is TRUE.

See also

isStealFocus

Since

SoQt 1.3.0

SbBool SoQtGLWidget::isStealFocus (void) const

Returns whether focus stealing policy is on (TRUE) or off (FALSE).

Default is TRUE.

See also

setStealFocus

Since

SoQt 1.3.0

QWidget * SoQtGLWidget::getGLWidget (void) const

Returns a pointer to the toolkit-native GL widget.

QWidget * SoQtGLWidget::getNormalWidget (void) const

For SoQt, this returns the same widget pointer as that of SoQtGLWidget::getGLWidget().

QWidget * SoQtGLWidget::getOverlayWidget (void) const

Returns widget associated with overlay planes, or NULL if no overlay planes are available.

For the Qt toolkit, overlay planes is a feature of the QGLWidget, and not seen at a separate widget entity. So this call will just return the same widget reference as the SoQt::getGLWidget() call (if overlay planes are supported).

SbBool SoQtGLWidget::hasOverlayGLArea (void) const

Will return TRUE if an overlay GL drawing area exists.

SbBool SoQtGLWidget::hasNormalGLArea (void) const

Will return TRUE if a normal GL drawing area exists.

unsigned long SoQtGLWidget::getOverlayTransparentPixel (void)

Returns the overlay transparent pixel.

void SoQtGLWidget::getPointSizeLimits (SbVec2f & range, float & granularity)

This function is provided as a convenience for the application programmer to help with acquiring the OpenGL implementation limits for rendering points.

For robust application code, one needs to consider the range limits when setting the SoDrawStyle::pointSize field.

void SoQtGLWidget::getLineWidthLimits (SbVec2f & range, float & granularity)

This function is provided as a convenience for the application programmer to help with acquiring the OpenGL implementation limits for rendering lines.

For robust application code, one needs to consider the range limits when setting the SoDrawStyle::lineWidth field.

void SoQtGLWidget::processEvent (QEvent * anyevent) [protected], [virtual]

Any events from the native window system that goes to the OpenGL canvas gets piped through this method.

It is overridden in the subclasses to catch user interaction with the render canvas in the viewers, as well as forwarding relevant events to the scene graph.

Reimplemented in SoQtRenderArea.

QWidget * SoQtGLWidget::buildWidget (QWidget * parent) [protected]

This method builds the component contents in the given parent widget. For subclasses adding new user interface items, this method is typically overridden in the following manner:

QWidget * MyOwnViewer::buildWidget(QWidget * parent)
{
   QWidget * superw = <superclass>::buildWidget(parent);
   // [then move superw within MyOwnViewer framework and add own
   // user interface components]
}

void SoQtGLWidget::redraw (void) [protected], [pure virtual]

This method is invoked when the GL buffer needs to be redrawn.

Implemented in SoQtRenderArea.

void SoQtGLWidget::redrawOverlay (void) [protected], [virtual]

Renders the overlay scene graph. Default method is empty. Subclasses should override this method.

Reimplemented in SoQtRenderArea.

void SoQtGLWidget::initGraphic (void) [protected], [virtual]

Will be called when GL widget should initialize graphic, after the widget has been created. Default method enabled GL_DEPTH_TEST.

Reimplemented in SoQtRenderArea.

void SoQtGLWidget::initOverlayGraphic (void) [protected], [virtual]

Will be called after the overlay widget has been created, and subclasses should override this to initialize overlay stuff.

Default method does nothing.

Reimplemented in SoQtRenderArea.

void SoQtGLWidget::sizeChanged (const SbVec2s & size) [protected], [virtual]

Called internally from within the SoQt library when the widget embedded in a component changes its size, which is usually triggered by end-user interaction.

This method is then invoked to notify the component that the size has changed. It is called from the top and all the way down to the bottom, the size being adjusted to take into account extra decorations having been added at each level in the component class hierarchy.

Reimplemented from SoQtComponent.

Reimplemented in SoQtViewer, SoQtFullViewer, and SoQtRenderArea.

void SoQtGLWidget::widgetChanged (QWidget * w) [protected], [virtual]

This is the method which gets called whenever we change which OpenGL widget is used.

Should be overridden in subclasses which directly or indirectly store the return value from the SoQtGLWidget::getGLWidget() method.

See also

sizeChanged()

Reimplemented in SoQtRenderArea.

void SoQtGLWidget::setGLSize (const SbVec2s size) [protected]

Sets the size of the GL canvas.

SbVec2s SoQtGLWidget::getGLSize (void) const [protected]

Return the dimensions of the OpenGL canvas.

float SoQtGLWidget::getGLAspectRatio (void) const [protected]

Return the aspect ratio of the OpenGL canvas.

void SoQtGLWidget::setGlxSize (const SbVec2s size) [inline], [protected]

This function has been renamed to the more appropriate setGLSize.

See also

setGLSize

SbVec2s SoQtGLWidget::getGlxSize (void) const [inline], [protected]

This function has been renamed to the more appropriate getGLSize.

See also

getGLSize

float SoQtGLWidget::getGlxAspectRatio (void) const [inline], [protected]

This function has been renamed to the more appropriate getGLAspectRatio.

See also

getGLAspectRatio

void SoQtGLWidget::setStereoBuffer (SbBool flag) [protected]

Sets whether OpenGL stereo buffers (quad buffer stereo) should be used.

SbBool SoQtGLWidget::isStereoBuffer (void) const [protected]

Returns whether OpenGL stereo buffers are being used.

SbBool SoQtGLWidget::isRGBMode (void) [protected]

Returns TRUE if the normal GL context is in RGBA mode. Return FALSE if color index mode is used.

void SoQtGLWidget::glLockNormal (void) [protected]

This method calls make-current on the correct context and increases the lock level.

void SoQtGLWidget::glUnlockNormal (void) [protected]

This method decreases the lock level.

void SoQtGLWidget::glLockOverlay (void) [protected]

This method calls make-current on the correct context and increases the lock level.

void SoQtGLWidget::glUnlockOverlay (void) [protected]

This method decreases the lock level.

void SoQtGLWidget::glSwapBuffers (void) [protected]

Swap back buffer to front and vice versa.

void SoQtGLWidget::glFlushBuffer (void) [protected]

Flush the current GL buffer. Simply calls glFlush().

SbBool SoQtGLWidget::glScheduleRedraw (void) [protected], [virtual]

Will be called whenever scene graph needs to be redrawn. If this method return FALSE, redraw() will be called immediately.

Default method simply returns FALSE. Override this method to schedule a redraw and return TRUE if you're trying to do The Right Thing.

Reimplemented in SoQtRenderArea.

Member Data Documentation

SbBool SoQtGLWidget::waitForExpose [protected]

If this is TRUE, rendering should not be done yet. Upon the first expose event of a newly created OpenGL widget, this variable will be set to FALSE.

SbBool SoQtGLWidget::drawToFrontBuffer [protected]

If this is TRUE, rendering will happen in the front buffer even if the current rendering mode is double buffered.

Author

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Info

Mon Jan 25 2021 Version 1.6.0 SoQt