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QSurfaceFormat ClassThe QSurfaceFormat class represents the format of a QSurface. More... #include <QSurfaceFormat>This class was introduced in Qt 5.0. Public Types
Public Functions
Related Non-Members
Detailed DescriptionThe QSurfaceFormat class represents the format of a QSurface. The format includes the size of the color buffers, red, green, and blue; the size of the alpha buffer; the size of the depth and stencil buffers; and number of samples per pixel for multisampling. In addition, the format contains surface configuration parameters such as OpenGL profile and version for rendering, whether or not enable stereo buffers, and swap behaviour. Member Type Documentation
flags QSurfaceFormat::FormatOptions |
| Constant | Value | Description |
|---|---|---|
| QSurfaceFormat::StereoBuffers | 0x0001 | Used to request stereo buffers in the surface format. |
| QSurfaceFormat::DebugContext | 0x0002 | Used to request a debug context with extra debugging information. This requires OpenGL version 3.0 or higher. |
| QSurfaceFormat::DeprecatedFunctions | 0x0004 | Used to request that deprecated functions be included in the OpenGL context profile. If not specified, you should get a forward compatible context without support functionality marked as deprecated. This requires OpenGL version 3.0 or higher. |
The FormatOptions type is a typedef for QFlags<FormatOption>. It stores an OR combination of FormatOption values.
enum QSurfaceFormat::OpenGLContextProfile
This enum is used to specify the OpenGL context profile, in conjunction with QSurfaceFormat::setMajorVersion() and QSurfaceFormat::setMinorVersion().
Profiles are exposed in OpenGL 3.2 and above, and are used to choose between a restricted core profile, and a compatibility profile which might contain deprecated support functionality.
Note that the core profile might still contain functionality that is deprecated and scheduled for removal in a higher version. To get access to the deprecated functionality for the core profile in the set OpenGL version you can use the QSurfaceFormat format option QSurfaceFormat::DeprecatedFunctions.
| Constant | Value | Description |
|---|---|---|
| QSurfaceFormat::NoProfile | 0 | OpenGL version is lower than 3.2. |
| QSurfaceFormat::CoreProfile | 1 | Functionality deprecated in OpenGL version 3.0 is not available. |
| QSurfaceFormat::CompatibilityProfile | 2 | Functionality from earlier OpenGL versions is available. |
enum QSurfaceFormat::SwapBehavior
This enum is used by QSurfaceFormat to specify the swap behaviour of a surface. The swap behaviour is mostly transparent to the application, but it affects factors such as rendering latency and throughput.
| Constant | Value | Description |
|---|---|---|
| QSurfaceFormat::DefaultSwapBehavior | 0 | The default, unspecified swap behaviour of the platform. |
| QSurfaceFormat::SingleBuffer | 1 | Used to request single buffering, which might result in flickering when OpenGL rendering is done directly to screen without an intermediate offscreen buffer. |
| QSurfaceFormat::DoubleBuffer | 2 | This is typically the default swap behaviour on desktop platforms, consisting of one back buffer and one front buffer. Rendering is done to the back buffer, and then the back buffer and front buffer are swapped, or the contents of the back buffer are copied to the front buffer, depending on the implementation. |
| QSurfaceFormat::TripleBuffer | 3 | This swap behaviour is sometimes used in order to decrease the risk of skipping a frame when the rendering rate is just barely keeping up with the screen refresh rate. Depending on the platform it might also lead to slightly more efficient use of the GPU due to improved pipelining behaviour. Triple buffering comes at the cost of an extra frame of memory usage and latency, and might not be supported depending on the underlying platform. |
Member Function Documentation
QSurfaceFormat::QSurfaceFormat()
Constructs a default initialized QSurfaceFormat.
QSurfaceFormat::QSurfaceFormat(FormatOptions options)
Constructs a QSurfaceFormat with the given format options.
QSurfaceFormat::QSurfaceFormat(const QSurfaceFormat & other)
Constructs a copy of other.
QSurfaceFormat::~QSurfaceFormat()
Destroys the QSurfaceFormat.
int QSurfaceFormat::alphaBufferSize() const
Get the size in bits of the alpha channel of the color buffer.
See also setAlphaBufferSize().
int QSurfaceFormat::blueBufferSize() const
Get the size in bits of the blue channel of the color buffer.
See also setBlueBufferSize().
int QSurfaceFormat::depthBufferSize() const
Returns the depth buffer size.
See also depth(), setDepth(), and setDepthBufferSize().
int QSurfaceFormat::greenBufferSize() const
Get the size in bits of the green channel of the color buffer.
See also setGreenBufferSize().
bool QSurfaceFormat::hasAlpha() const
Returns true if the alpha buffer size is greater than zero.
This means that the surface might be used with per pixel translucency effects.
int QSurfaceFormat::majorVersion() const
Returns the major OpenGL version.
The default version is 2.0.
See also setMajorVersion().
int QSurfaceFormat::minorVersion() const
Returns the minor OpenGL version.
See also setMinorVersion().
OpenGLContextProfile QSurfaceFormat::profile() const
Get the configured OpenGL context profile.
This setting is ignored if the requested OpenGL version is less than 3.2.
See also setProfile().
int QSurfaceFormat::redBufferSize() const
Get the size in bits of the red channel of the color buffer.
See also setRedBufferSize().
int QSurfaceFormat::samples() const
Returns the number of samples per pixel when multisampling is enabled. By default, multisampling is disabled.
See also setSampleBuffers(), sampleBuffers(), and setSamples().
void QSurfaceFormat::setAlphaBufferSize(int size)
Set the desired size in bits of the alpha channel of the color buffer.
See also alphaBufferSize().
void QSurfaceFormat::setBlueBufferSize(int size)
Set the desired size in bits of the blue channel of the color buffer.
See also blueBufferSize().
void QSurfaceFormat::setDepthBufferSize(int size)
Set the minimum depth buffer size to size.
See also depthBufferSize(), setDepth(), and depth().
void QSurfaceFormat::setGreenBufferSize(int size)
Set the desired size in bits of the green channel of the color buffer.
See also greenBufferSize().
void QSurfaceFormat::setMajorVersion(int major)
Sets the desired major OpenGL version.
See also majorVersion().
void QSurfaceFormat::setMinorVersion(int minor)
Sets the desired minor OpenGL version.
The default version is 2.0.
See also minorVersion().
void QSurfaceFormat::setOption(QSurfaceFormat::FormatOptions opt)
Sets the format option to opt.
See also testOption().
void QSurfaceFormat::setProfile(OpenGLContextProfile profile)
Sets the desired OpenGL context profile.
This setting is ignored if the requested OpenGL version is less than 3.2.
See also profile().
void QSurfaceFormat::setRedBufferSize(int size)
Set the desired size in bits of the red channel of the color buffer.
See also redBufferSize().
void QSurfaceFormat::setSamples(int numSamples)
Set the preferred number of samples per pixel when multisampling is enabled to numSamples. By default, multisampling is disabled.
See also setSampleBuffers(), sampleBuffers(), and samples().
void QSurfaceFormat::setStencilBufferSize(int size)
Set the preferred stencil buffer size to size bits.
See also stencilBufferSize(), setStencil(), and stencil().
void QSurfaceFormat::setStereo(bool enable)
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().
void QSurfaceFormat::setSwapBehavior(SwapBehavior behavior)
Set the swap behaviour of the surface.
The swap behaviour specifies whether single, double, or triple buffering is desired. The default, SwapBehavior::DefaultSwapBehavior, gives the default swap behavior of the platform.
See also swapBehavior().
int QSurfaceFormat::stencilBufferSize() const
Returns the stencil buffer size in bits.
See also stencil(), setStencil(), and setStencilBufferSize().
bool QSurfaceFormat::stereo() const
Returns true if stereo buffering is enabled; otherwise returns false. Stereo buffering is disabled by default.
See also setStereo().
SwapBehavior QSurfaceFormat::swapBehavior() const
Returns the configured swap behaviour.
See also setSwapBehavior().
bool QSurfaceFormat::testOption(QSurfaceFormat::FormatOptions opt) const
Returns true if format option opt is set; otherwise returns false.
See also setOption().
QSurfaceFormat & QSurfaceFormat::operator=(const QSurfaceFormat & other)
Assigns other to this object.
Related Non-Members
bool operator!=(const QSurfaceFormat & a, const QSurfaceFormat & b)
Returns false if all the options of the two QSurfaceFormat objects a and b are equal; otherwise returns true.
bool operator==(const QSurfaceFormat & a, const QSurfaceFormat & b)
Returns true if all the options of the two QSurfaceFormat objects are equal.