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phoenix_title GLCanvas

GLCanvas is a class for displaying OpenGL graphics.

It is always used in conjunction with GLContext as the context can only be made current (i.e. active for the OpenGL commands) when it is associated to a GLCanvas.

More precisely, you first need to create a GLCanvas window and then create an instance of a GLContext that is initialized with this GLCanvas and then later use either SetCurrent with the instance of the GLContext or GLContext.SetCurrent with the instance of the GLCanvas (which might be not the same as was used for the creation of the context) to bind the OpenGL state that is represented by the rendering context to the canvas, and then finally call SwapBuffers to swap the buffers of the OpenGL canvas and thus show your current output.

Notice that versions of wxWidgets previous to 2.9 used to implicitly create a GLContext inside GLCanvas itself. This is still supported in the current version but is deprecated now and will be removed in the future, please update your code to create the rendering contexts explicitly.

To set up the attributes for the canvas (number of bits for the depth buffer, number of bits for the stencil buffer and so on) you should set up the correct values of the attribList parameter. The values that should be set up and their meanings will be described below.

Note

On those platforms which use a configure script (e.g. Linux and Mac OS) OpenGL support is automatically enabled if the relative headers and libraries are found. To switch it on under the other platforms (e.g. Windows), you need to edit the setup.h file and set USE_GLCANVAS to 1 and then also pass USE_OPENGL=1 to the make utility. You may also need to add opengl32.lib and glu32.lib to the list of the libraries your program is linked with.

See also

GLContext


class_hierarchy Class Hierarchy

Inheritance diagram for class GLCanvas:


method_summary Methods Summary

__init__ Creates a window with the given parameters.
IsDisplaySupported Determines if a canvas having the specified attributes is available.
IsExtensionSupported Returns True if the extension with given name is supported.
SetColour Sets the current colour for this window (using glcolor3f() ), using the wxWidgets colour database to find a named colour.
SetCurrent Makes the OpenGL state that is represented by the OpenGL rendering context context current, i.e.
SwapBuffers Swaps the double-buffer of this window, making the back-buffer the front-buffer and vice versa, so that the output of the previous OpenGL commands is displayed on the window.

api Class API



class GLCanvas(Window)

Possible constructors:

GLCanvas(self, parent, id=ID_ANY, attribList=None, pos=DefaultPosition,
         size=DefaultSize, style=0, name='GLCanvas', palette=NullPalette)

GLCanvas is a class for displaying OpenGL graphics.


Methods



static IsDisplaySupported(attribList)

Determines if a canvas having the specified attributes is available.

Parameters:attribList (list of integers) – See attribList for GLCanvas .
Return type:bool
Returns:True if attributes are supported.


static IsExtensionSupported(extension)

Returns True if the extension with given name is supported.

Notice that while this function is implemented for all of GLX, WGL and AGL the extensions names are usually not the same for different platforms and so the code using it still usually uses conditional compilation.

Parameters:extension (int) –
Return type:bool


SetColour(self, colour)

Sets the current colour for this window (using glcolor3f() ), using the wxWidgets colour database to find a named colour.

Parameters:colour (string) –
Return type:bool


SetCurrent(self, context)

Makes the OpenGL state that is represented by the OpenGL rendering context context current, i.e.

it will be used by all subsequent OpenGL calls.

This is equivalent to GLContext.SetCurrent called with this window as parameter.

Parameters:context (GLContext) –
Return type:bool
Returns:False if an error occurred.

Note

This function may only be called when the window is shown on screen, in particular it can’t usually be called from the constructor as the window isn’t yet shown at this moment.



SwapBuffers(self)

Swaps the double-buffer of this window, making the back-buffer the front-buffer and vice versa, so that the output of the previous OpenGL commands is displayed on the window.

Return type:bool
Returns:False if an error occurred.