QGLFormat

The QGLFormat class specifies the display format of an OpenGL rendering context. More

Inheritance diagram of PySide2.QtOpenGL.QGLFormat

Synopsis

Functions

Static functions

Detailed Description

A display format has several characteristics:

You can also specify preferred bit depths for the color buffer, depth buffer, alpha buffer, accumulation buffer and the stencil buffer with the functions: setRedBufferSize() , setGreenBufferSize() , setBlueBufferSize() , setDepthBufferSize() , setAlphaBufferSize() , setAccumBufferSize() and setStencilBufferSize() .

Note that even if you specify that you prefer a 32 bit depth buffer (e.g. with setDepthBufferSize (32)), the format that is chosen may not have a 32 bit depth buffer, even if there is a format available with a 32 bit depth buffer. The main reason for this is how the system dependant picking algorithms work on the different platforms, and some format options may have higher precedence than others.

You create and tell a QGLFormat object what rendering options you want from an OpenGL rendering context.

OpenGL drivers or accelerated hardware may or may not support advanced features such as alpha channel or stereographic viewing. If you request some features that the driver/hardware does not provide when you create a QGLWidget , you will get a rendering context with the nearest subset of features.

There are different ways to define the display characteristics of a rendering context. One is to create a QGLFormat and make it the default for the entire application:

fmt = QGLFormat()
fmt.setAlpha(True)
fmt.setStereo(True)
QGLFormat.setDefaultFormat(fmt)

Or you can specify the desired format when creating an object of your QGLWidget subclass:

fmt = QGLFormat()
fmt.setDoubleBuffer(False)                 # single buffer
fmt.setDirectRendering(False)              # software rendering
myWidget = MyGLWidget(fmt, ...)

After the widget has been created, you can find out which of the requested features the system was able to provide:

fmt = QGLFormat()
fmt.setOverlay(True)
fmt.setStereo(True)
myWidget = MyGLWidget(fmt, ...)
if !myWidget.format().stereo():
    # ok, goggles off
    if !myWidget.format().hasOverlay():
        print "Cool hardware required"
OpenGL is a trademark of Silicon Graphics, Inc. in the United States and other countries.
class QGLFormat

QGLFormat(options[, plane=0])

QGLFormat(other)

param plane

int

param other

QGLFormat

param options

FormatOptions

Constructs a QGLFormat object with the following default settings:

Creates a QGLFormat object that is a copy of the current defaultFormat() .

If options is not 0, the default format is modified by the specified format options. The options parameter should be FormatOption values OR’ed together.

This constructor makes it easy to specify a certain desired format in classes derived from QGLWidget , for example:

# The rendering in MyGLWidget depends on using
# stencil buffer and alpha channel

class MyGLWidget(QGLWidget):
    def __init__(self, parent):
        QGLWidget.__init__(self, QGLFormat(QGL.StencilBuffer | QGL.AlphaChannel), parent)

        if !format().stencil():
            print "Could not get stencil buffer results will be suboptimal"
        if !format().alpha():
            print "Could not get alpha channel results will be suboptimal"
    ...

Note that there are FormatOption values to turn format settings both on and off, e.g. DepthBuffer and NoDepthBuffer , DirectRendering and IndirectRendering , etc.

The plane parameter defaults to 0 and is the plane which this format should be associated with. Not all OpenGL implementations supports overlay/underlay rendering planes.

Constructs a copy of other .

PySide2.QtOpenGL.QGLFormat.OpenGLContextProfile

This enum describes the OpenGL context profiles that can be specified for contexts implementing OpenGL version 3.2 or higher. These profiles are different from OpenGL ES profiles.

Constant

Description

QGLFormat.NoProfile

OpenGL version is lower than 3.2.

QGLFormat.CoreProfile

Functionality deprecated in OpenGL version 3.0 is not available.

QGLFormat.CompatibilityProfile

Functionality from earlier OpenGL versions is available.

New in version 4.7.

PySide2.QtOpenGL.QGLFormat.OpenGLVersionFlag

This enum describes the various OpenGL versions that are recognized by Qt. Use the openGLVersionFlags() function to identify which versions that are supported at runtime.

Constant

Description

QGLFormat.OpenGL_Version_None

If no OpenGL is present or if no OpenGL context is current.

QGLFormat.OpenGL_Version_1_1

OpenGL version 1.1 or higher is present.

QGLFormat.OpenGL_Version_1_2

OpenGL version 1.2 or higher is present.

QGLFormat.OpenGL_Version_1_3

OpenGL version 1.3 or higher is present.

QGLFormat.OpenGL_Version_1_4

OpenGL version 1.4 or higher is present.

QGLFormat.OpenGL_Version_1_5

OpenGL version 1.5 or higher is present.

QGLFormat.OpenGL_Version_2_0

OpenGL version 2.0 or higher is present. Note that version 2.0 supports all the functionality of version 1.5.

QGLFormat.OpenGL_Version_2_1

OpenGL version 2.1 or higher is present.

QGLFormat.OpenGL_Version_3_0

OpenGL version 3.0 or higher is present.

QGLFormat.OpenGL_Version_3_1

OpenGL version 3.1 or higher is present. Note that OpenGL version 3.1 or higher does not necessarily support all the features of version 3.0 and lower.

QGLFormat.OpenGL_Version_3_2

OpenGL version 3.2 or higher is present.

QGLFormat.OpenGL_Version_3_3

OpenGL version 3.3 or higher is present.

QGLFormat.OpenGL_Version_4_0

OpenGL version 4.0 or higher is present.

QGLFormat.OpenGL_Version_4_1

OpenGL version 4.1 or higher is present.

QGLFormat.OpenGL_Version_4_2

OpenGL version 4.2 or higher is present.

QGLFormat.OpenGL_Version_4_3

OpenGL version 4.3 or higher is present.

QGLFormat.OpenGL_ES_CommonLite_Version_1_0

OpenGL ES version 1.0 Common Lite or higher is present.

QGLFormat.OpenGL_ES_Common_Version_1_0

OpenGL ES version 1.0 Common or higher is present. The Common profile supports all the features of Common Lite.

QGLFormat.OpenGL_ES_CommonLite_Version_1_1

OpenGL ES version 1.1 Common Lite or higher is present.

QGLFormat.OpenGL_ES_Common_Version_1_1

OpenGL ES version 1.1 Common or higher is present. The Common profile supports all the features of Common Lite.

QGLFormat.OpenGL_ES_Version_2_0

OpenGL ES version 2.0 or higher is present. Note that OpenGL ES version 2.0 does not support all the features of OpenGL ES 1.x. So if is returned, none of the ES 1.x flags are returned.

See also http://www.opengl.org for more information about the different revisions of OpenGL.

PySide2.QtOpenGL.QGLFormat.accum()
Return type

bool

Returns true if the accumulation buffer is enabled; otherwise returns false . The accumulation buffer is disabled by default.

PySide2.QtOpenGL.QGLFormat.accumBufferSize()
Return type

int

Returns the accumulation buffer size.

PySide2.QtOpenGL.QGLFormat.alpha()
Return type

bool

Returns true if the alpha buffer in the framebuffer is enabled; otherwise returns false . The alpha buffer is disabled by default.

PySide2.QtOpenGL.QGLFormat.alphaBufferSize()
Return type

int

Returns the alpha buffer size.

PySide2.QtOpenGL.QGLFormat.blueBufferSize()
Return type

int

Returns the blue buffer size.

static PySide2.QtOpenGL.QGLFormat.defaultFormat()
Return type

QGLFormat

Returns the default QGLFormat for the application. All QGLWidget objects that are created use this format unless another format is specified, e.g. when they are constructed.

If no special default format has been set using setDefaultFormat() , the default format is the same as that created with QGLFormat() .

static PySide2.QtOpenGL.QGLFormat.defaultOverlayFormat()
Return type

QGLFormat

Returns the default QGLFormat for overlay contexts.

The default overlay format is:

PySide2.QtOpenGL.QGLFormat.depth()
Return type

bool

Returns true if the depth buffer is enabled; otherwise returns false. The depth buffer is enabled by default.

PySide2.QtOpenGL.QGLFormat.depthBufferSize()
Return type

int

Returns the depth buffer size.

PySide2.QtOpenGL.QGLFormat.directRendering()
Return type

bool

Returns true if direct rendering is enabled; otherwise returns false.

Direct rendering is enabled by default.

PySide2.QtOpenGL.QGLFormat.doubleBuffer()
Return type

bool

Returns true if double buffering is enabled; otherwise returns false. Double buffering is enabled by default.

static PySide2.QtOpenGL.QGLFormat.fromSurfaceFormat(format)
Parameters

formatQSurfaceFormat

Return type

QGLFormat

Returns an OpenGL format for the window format specified by format .

PySide2.QtOpenGL.QGLFormat.greenBufferSize()
Return type

int

Returns the green buffer size.

static PySide2.QtOpenGL.QGLFormat.hasOpenGL()
Return type

bool

Returns true if the window system has any OpenGL support; otherwise returns false .

Warning

This function must not be called until the QApplication object has been created.

static PySide2.QtOpenGL.QGLFormat.hasOpenGLOverlays()
Return type

bool

Returns true if the window system supports OpenGL overlays; otherwise returns false .

Warning

This function must not be called until the QApplication object has been created.

PySide2.QtOpenGL.QGLFormat.hasOverlay()
Return type

bool

Returns true if overlay plane is enabled; otherwise returns false .

Overlay is disabled by default.

See also

setOverlay()

PySide2.QtOpenGL.QGLFormat.majorVersion()
Return type

int

Returns the OpenGL major version.

PySide2.QtOpenGL.QGLFormat.minorVersion()
Return type

int

Returns the OpenGL minor version.

static PySide2.QtOpenGL.QGLFormat.openGLVersionFlags()
Return type

OpenGLVersionFlags

Identifies, at runtime, which OpenGL versions that are supported by the current platform.

Note that if OpenGL version 1.5 is supported, its predecessors (i.e., version 1.4 and lower) are also supported. To identify the support of a particular feature, like multi texturing, test for the version in which the feature was first introduced (i.e., version 1.3 in the case of multi texturing) to adapt to the largest possible group of runtime platforms.

This function needs a valid current OpenGL context to work; otherwise it will return OpenGL_Version_None .

PySide2.QtOpenGL.QGLFormat.__ne__(arg__2)
Parameters

arg__2QGLFormat

Return type

bool

PySide2.QtOpenGL.QGLFormat.__eq__(arg__2)
Parameters

arg__2QGLFormat

Return type

bool

PySide2.QtOpenGL.QGLFormat.plane()
Return type

int

Returns the plane of this format. The default for normal formats is 0, which means the normal plane. The default for overlay formats is 1, which is the first overlay plane.

PySide2.QtOpenGL.QGLFormat.profile()
Return type

OpenGLContextProfile

Returns the OpenGL context profile.

See also

setProfile()

PySide2.QtOpenGL.QGLFormat.redBufferSize()
Return type

int

Returns the red buffer size.

PySide2.QtOpenGL.QGLFormat.rgba()
Return type

bool

Returns true if RGBA color mode is set. Returns false if color index mode is set. The default color mode is RGBA.

See also

setRgba()

PySide2.QtOpenGL.QGLFormat.sampleBuffers()
Return type

bool

Returns true if multisample buffer support is enabled; otherwise returns false .

The multisample buffer is disabled by default.

PySide2.QtOpenGL.QGLFormat.samples()
Return type

int

Returns the number of samples per pixel when multisampling is enabled. By default, the highest number of samples that is available is used.

PySide2.QtOpenGL.QGLFormat.setAccum(enable)
Parameters

enablebool

If enable is true enables the accumulation buffer; otherwise disables the accumulation buffer.

The accumulation buffer is disabled by default.

The accumulation buffer is used to create blur effects and multiple exposures.

PySide2.QtOpenGL.QGLFormat.setAccumBufferSize(size)
Parameters

sizeint

Set the preferred accumulation buffer size, where size is the bit depth for each RGBA component.

PySide2.QtOpenGL.QGLFormat.setAlpha(enable)
Parameters

enablebool

If enable is true enables the alpha buffer; otherwise disables the alpha buffer.

The alpha buffer is disabled by default.

The alpha buffer is typically used for implementing transparency or translucency. The A in RGBA specifies the transparency of a pixel.

PySide2.QtOpenGL.QGLFormat.setAlphaBufferSize(size)
Parameters

sizeint

Set the preferred alpha buffer size to size . This function implicitly enables the alpha channel.

PySide2.QtOpenGL.QGLFormat.setBlueBufferSize(size)
Parameters

sizeint

Set the preferred blue buffer size to size .

static PySide2.QtOpenGL.QGLFormat.setDefaultFormat(f)
Parameters

fQGLFormat

Sets a new default QGLFormat for the application to f . For example, to set single buffering as the default instead of double buffering, your main() might contain code like this:

a = QApplication([])
f = QGLFormat()
f.setDoubleBuffer(False)
QGLFormat.setDefaultFormat(f)

See also

defaultFormat()

static PySide2.QtOpenGL.QGLFormat.setDefaultOverlayFormat(f)
Parameters

fQGLFormat

Sets a new default QGLFormat for overlay contexts to f . This format is used whenever a QGLWidget is created with a format that hasOverlay() enabled.

For example, to get a double buffered overlay context (if available), use code like this:

f = QGLFormat.defaultOverlayFormat()
f.setDoubleBuffer(True)
QGLFormat.setDefaultOverlayFormat(f)

As usual, you can find out after widget creation whether the underlying OpenGL system was able to provide the requested specification:

# ...continued from above
myWidget = MyGLWidget(QGLFormat(QGL.HasOverlay), ...)
if myWidget.format().hasOverlay():
    # Yes, we got an overlay, let's check _its_ format:
    olContext = myWidget.overlayContext()
    if olContext.format().doubleBuffer():
         # yes, we got a double buffered overlay
    else:
         # no, only single buffered overlays are available
PySide2.QtOpenGL.QGLFormat.setDepth(enable)
Parameters

enablebool

If enable is true enables the depth buffer; otherwise disables the depth buffer.

The depth buffer is enabled by default.

The purpose of a depth buffer (or Z-buffering) is to remove hidden surfaces. Pixels are assigned Z values based on the distance to the viewer. A pixel with a high Z value is closer to the viewer than a pixel with a low Z value. This information is used to decide whether to draw a pixel or not.

PySide2.QtOpenGL.QGLFormat.setDepthBufferSize(size)
Parameters

sizeint

Set the minimum depth buffer size to size .

PySide2.QtOpenGL.QGLFormat.setDirectRendering(enable)
Parameters

enablebool

If enable is true enables direct rendering; otherwise disables direct rendering.

Direct rendering is enabled by default.

Enabling this option will make OpenGL bypass the underlying window system and render directly from hardware to the screen, if this is supported by the system.

PySide2.QtOpenGL.QGLFormat.setDoubleBuffer(enable)
Parameters

enablebool

If enable is true sets double buffering; otherwise sets single buffering.

Double buffering is enabled by default.

Double buffering is a technique where graphics are rendered on an off-screen buffer and not directly to the screen. When the drawing has been completed, the program calls a swapBuffers() function to exchange the screen contents with the buffer. The result is flicker-free drawing and often better performance.

Note that single buffered contexts are currently not supported with EGL.

PySide2.QtOpenGL.QGLFormat.setGreenBufferSize(size)
Parameters

sizeint

Set the preferred green buffer size to size .

PySide2.QtOpenGL.QGLFormat.setOption(opt)
Parameters

optFormatOptions

Sets the format option to opt .

See also

testOption()

PySide2.QtOpenGL.QGLFormat.setOverlay(enable)
Parameters

enablebool

If enable is true enables an overlay plane; otherwise disables the overlay plane.

Enabling the overlay plane will cause QGLWidget to create an additional context in an overlay plane. See the QGLWidget documentation for further information.

See also

hasOverlay()

PySide2.QtOpenGL.QGLFormat.setPlane(plane)
Parameters

planeint

Sets the requested plane to plane . 0 is the normal plane, 1 is the first overlay plane, 2 is the second overlay plane, etc.; -1, -2, etc. are underlay planes.

Note that in contrast to other format specifications, the plane specifications will be matched exactly. This means that if you specify a plane that the underlying OpenGL system cannot provide, an invalid QGLWidget will be created.

See also

plane()

PySide2.QtOpenGL.QGLFormat.setProfile(profile)
Parameters

profileOpenGLContextProfile

Set the OpenGL context profile to profile . The profile is ignored if the requested OpenGL version is less than 3.2.

See also

profile()

PySide2.QtOpenGL.QGLFormat.setRedBufferSize(size)
Parameters

sizeint

Set the preferred red buffer size to size .

PySide2.QtOpenGL.QGLFormat.setRgba(enable)
Parameters

enablebool

If enable is true sets RGBA mode. If enable is false sets color index mode.

The default color mode is RGBA.

RGBA is the preferred mode for most OpenGL applications. In RGBA color mode you specify colors as red + green + blue + alpha quadruplets.

In color index mode you specify an index into a color lookup table.

See also

rgba()

PySide2.QtOpenGL.QGLFormat.setSampleBuffers(enable)
Parameters

enablebool

If enable is true, a GL context with multisample buffer support is picked; otherwise ignored.

PySide2.QtOpenGL.QGLFormat.setSamples(numSamples)
Parameters

numSamplesint

Set the preferred number of samples per pixel when multisampling is enabled to numSamples . By default, the highest number of samples available is used.

PySide2.QtOpenGL.QGLFormat.setStencil(enable)
Parameters

enablebool

If enable is true enables the stencil buffer; otherwise disables the stencil buffer.

The stencil buffer is enabled by default.

The stencil buffer masks certain parts of the drawing area so that masked parts are not drawn on.

PySide2.QtOpenGL.QGLFormat.setStencilBufferSize(size)
Parameters

sizeint

Set the preferred stencil buffer size to size .

PySide2.QtOpenGL.QGLFormat.setStereo(enable)
Parameters

enablebool

If enable is true enables stereo buffering; otherwise disables stereo buffering.

Stereo buffering is disabled by default.

Stereo buffering provides extra color buffers to generate left-eye and right-eye images.

See also

stereo()

PySide2.QtOpenGL.QGLFormat.setSwapInterval(interval)
Parameters

intervalint

Set the preferred swap interval. This can be used to sync the GL drawing into a system window to the vertical refresh of the screen. Setting an interval value of 0 will turn the vertical refresh syncing off, any value higher than 0 will turn the vertical syncing on.

Under Windows and under X11, where the WGL_EXT_swap_control and GLX_SGI_video_sync extensions are used, the interval parameter can be used to set the minimum number of video frames that are displayed before a buffer swap will occur. In effect, setting the interval to 10, means there will be 10 vertical retraces between every buffer swap.

Under Windows the WGL_EXT_swap_control extension has to be present, and under X11 the GLX_SGI_video_sync extension has to be present.

See also

swapInterval()

PySide2.QtOpenGL.QGLFormat.setVersion(major, minor)
Parameters
  • majorint

  • minorint

Set the OpenGL version to the major and minor numbers. If a context compatible with the requested OpenGL version cannot be created, a context compatible with version 1.x is created instead.

PySide2.QtOpenGL.QGLFormat.stencil()
Return type

bool

Returns true if the stencil buffer is enabled; otherwise returns false. The stencil buffer is enabled by default.

PySide2.QtOpenGL.QGLFormat.stencilBufferSize()
Return type

int

Returns the stencil buffer size.

PySide2.QtOpenGL.QGLFormat.stereo()
Return type

bool

Returns true if stereo buffering is enabled; otherwise returns false. Stereo buffering is disabled by default.

See also

setStereo()

PySide2.QtOpenGL.QGLFormat.swapInterval()
Return type

int

Returns the currently set swap interval. -1 is returned if setting the swap interval isn’t supported in the system GL implementation.

PySide2.QtOpenGL.QGLFormat.testOption(opt)
Parameters

optFormatOptions

Return type

bool

Returns true if format option opt is set; otherwise returns false .

See also

setOption()

static PySide2.QtOpenGL.QGLFormat.toSurfaceFormat(format)
Parameters

formatQGLFormat

Return type

QSurfaceFormat

Returns a window format for the OpenGL format specified by format .