Typedef for QFlags<BindOption>. Refer to QGLContext::BindOption for documentation.

Typedef for void(*)().

A set of options to decide how to bind a texture using bindTexture().

Deprecated:

Constructs an OpenGL context for the given paint device, which can be a widget or a pixmap. The format specifies several display options for the context.

If the underlying OpenGL/Window system can not satisfy all the features requested in format, the nearest subset of features will be used. After creation, the format() method will return the actual format obtained.

Note that after a QGLContext object has been constructed, create() must be called explicitly to create the actual OpenGL context. The context will be invalid if it was not possible to obtain a GL context at all.

Constructs an OpenGL context with the given format which specifies several display options for the context.

If the underlying OpenGL/Window system can not satisfy all the features requested in format, the nearest subset of features will be used. After creation, the format() method will return the actual format obtained.

Note that after a QGLContext object has been constructed, create() must be called explicitly to create the actual OpenGL context. The context will be invalid if it was not possible to obtain a GL context at all.

See also

format(), isValid()

Destroys the OpenGL context and frees its resources.

Returns true if context1 and context2 are sharing their GL resources such as textures, shader programs, etc, otherwise returns false.

Generates and binds a 2D GL texture to the current context, based on image. The generated texture id is returned and can be used in later glBindTexture() calls.

The target parameter specifies the texture target. The default target is GL_TEXTURE_2D.

The format parameter sets the internal format for the texture. The default format is GL_RGBA.

The binding options are a set of options used to decide how to bind the texture to the context.

The texture that is generated is cached, so multiple calls to bindTexture() with the same QImage will return the same texture id.

Note that we assume default values for the glPixelStore() and glPixelTransfer() parameters.

See also

deleteTexture()

Generates and binds a 2D GL texture to the current context, based on image. The generated texture id is returned and can be used in later glBindTexture() calls.

Generates and binds a 2D GL texture to the current context, based on pixmap.

Generates and binds a 2D GL texture based on pixmap.

Reads the compressed texture file fileName and generates a 2D GL texture from it.

This function can load DirectDrawSurface (DDS) textures in the DXT1, DXT3 and DXT5 DDS formats if the GL_ARB_texture_compression and GL_EXT_texture_compression_s3tc extensions are supported.

Textures in the ETC1 format can be loaded if the GL_OES_compressed_ETC1_RGB8_texture extension is supported and the ETC1 texture has been encapsulated in the PVR container format. Also, textures in the PVRTC2 and PVRTC4 formats can be loaded if the GL_IMG_texture_compression_pvrtc extension is supported.

See also

deleteTexture()

This semi-internal function is called by create(). It creates a system-dependent OpenGL handle that matches the format() of shareContext as closely as possible, returning true if successful or false if a suitable handle could not be found.

On Windows, it calls the virtual function choosePixelFormat(), which finds a matching pixel format identifier. On X11, it calls the virtual function chooseVisual() which finds an appropriate X visual. On other platforms it may work differently.

Creates the GL context. Returns true if it was successful in creating a valid GL rendering context on the paint device specified in the constructor, otherwise returns false (i.e. the context is invalid).

After successful creation, format() returns the set of features of the created GL rendering context.

If shareContext points to a valid QGLContext, this method will try to establish OpenGL display list and texture object sharing between this context and the shareContext. Note that this may fail if the two contexts have different formats. Use isSharing() to see if sharing is in effect.

Warning

Implementation note: initialization of C++ class members usually takes place in the class constructor. QGLContext is an exception because it must be simple to customize. The virtual functions chooseContext() (and chooseVisual() for X11) can be reimplemented in a subclass to select a particular context. The problem is that virtual functions are not properly called during construction (even though this is correct C++) because C++ constructs class hierarchies from the bottom up. For this reason we need a create() function.

See also

chooseContext(), format(), isValid()

Returns the current context, i.e. the context to which any OpenGL commands will currently be directed. Returns 0 if no context is current.

See also

makeCurrent()

Removes the texture identified by texture_id from the texture cache, and calls glDeleteTextures() to delete the texture from the context.

See also

bindTexture()

Returns the paint device set for this context.

See also

QGLContext::QGLContext()

Returns true if the paint device of this context is a pixmap, otherwise returns false.

Makes no GL context the current context. Normally, you do not need to call this function; QGLContext calls it as necessary.

This function supports the following use cases.

• By default it draws the given texture_id, at the given point in OpenGL model space. The textureTarget should be a 2D texture target.
• If a painter is active, not inside a beginNativePainting / endNativePainting block, and uses the engine with type QPaintEngine::OpenGL2, the function will draw the given texture_id, at the given point, respecting the current painter state. This will let you draw a texture with the clip, transform, render hints, and composition mode set by the painter. Note that the texture target needs to be GL_TEXTURE_2D for this use case.

Note

This method is not supported under any version of OpenGL ES.

This function supports the following use cases.

• On OpenGL and OpenGL ES 1.x it draws the given texture_id, to the given target rectangle, target, in OpenGL model space. The textureTarget should be a 2D texture target.
• On OpenGL and OpenGL ES 2.x, if a painter is active, not inside a beginNativePainting / endNativePainting block, and uses the engine with type QPaintEngine::OpenGL2, the function will draw the given texture_id, to the given target rectangle, target, respecting the current painter state. This will let you draw a texture with the clip, transform, render hints, and composition mode set by the painter. Note that the texture target needs to be GL_TEXTURE_2D for this use case, and that this is the only supported use case under OpenGL ES 2.x.

Returns the frame buffer format that was obtained (this may be a subset of what was requested).

See also

setFormat(), requestedFormat()

Returns a function pointer to the GL extension function passed in proc. A nullptr is returned if a pointer to the function could not be obtained.

Returns true if this context has been initialized, i.e. if QGLWidget::initializeGL() has been performed on it, otherwise returns false.

See also

setInitialized()

Returns true if this context is sharing its GL context with another QGLContext, otherwise false is returned. Note that context sharing might not be supported between contexts with different formats.

Returns true if a GL rendering context has been successfully created, otherwise returns false.

Makes this context the current OpenGL rendering context. All GL functions you call operate on this context until another context is made current.

In some very rare cases the underlying call may fail. If this occurs an error message is output to stderr.

If this context is a valid context in an overlay plane, returns the plane's transparent color. Otherwise returns an {QColor::isValid()}{invalid} color.

The returned QColor object will generally work as expected only when passed as the argument to QGLWidget::qglColor() or QGLWidget::qglClearColor(). Under certain circumstances it can also be used to draw transparent graphics with a QPainter.

Returns the frame buffer format that was originally requested in the constructor or setFormat().

See also

format()

Resets the context and makes it invalid.

See also

create(), isValid()

Sets a format for this context. The context is reset.

Call create() to create a new GL context that tries to match the new format.

See also

format(), reset(), create()

If on is true the context has been initialized, i.e. QGLContext::setInitialized() has been called on it. If on is false the context has not been initialized.

See also

initialized()

This function sets the limit for the texture cache to size, expressed in kilobytes.

By default, the cache limit is approximately 64 MB.

See also

textureCacheLimit()

If on is true the context has had a window created for it. If on is false no window has been created for the context.

See also

windowCreated()

Swaps the screen contents with an off-screen buffer. Only works if the context is in double buffer mode.

See also

QGLFormat::setDoubleBuffer()

Returns the current texture cache limit in kilobytes.

See also

setTextureCacheLimit()

Returns true if a window has been created for this context, otherwise returns false.

See also

setWindowCreated()