.. module:: glcanvas

====================
Module `wx.glcanvas`
====================

`GLcanvas` provides an OpenGL Context to `wx.Window <../Widgets/wx.Window.html>`_.

.. note:: Requires the PyOpenGL extension, available from http://PyOpenGL.sourceforge.net/


Usage
=====

The following example shows a simple implementation that utilizes `wx.glcanvas.GLCanvas <wx.glcanvas.GLCanvas.html>`_::

    import wx
    import sys

    from wx import glcanvas

    # The Python OpenGL package can be found at
    # http://PyOpenGL.sourceforge.net/
    from OpenGL.GL import *
    from OpenGL.GLUT import *

    class MyCanvasBase(glcanvas.GLCanvas):

        def __init__(self, parent):

            glcanvas.GLCanvas.__init__(self, parent, -1)
            self.init = False
            # initial mouse position
            self.lastx = self.x = 30
            self.lasty = self.y = 30
            self.size = None
            self.Bind(wx.EVT_ERASE_BACKGROUND, self.OnEraseBackground)
            self.Bind(wx.EVT_SIZE, self.OnSize)
            self.Bind(wx.EVT_PAINT, self.OnPaint)
            self.Bind(wx.EVT_LEFT_DOWN, self.OnMouseDown)
            self.Bind(wx.EVT_LEFT_UP, self.OnMouseUp)
            self.Bind(wx.EVT_MOTION, self.OnMouseMotion)


        def OnEraseBackground(self, event):
            pass # Do nothing, to avoid flashing on MSW.


        def OnSize(self, event):

            size = self.size = self.GetClientSize()
            if self.GetContext():
                self.SetCurrent()
                glViewport(0, 0, size.width, size.height)
            event.Skip()


        def OnPaint(self, event):

            dc = wx.PaintDC(self)
            self.SetCurrent()
            if not self.init:
                self.InitGL()
                self.init = True
            self.OnDraw()


        def OnMouseDown(self, evt):
            
            self.CaptureMouse()
            self.x, self.y = self.lastx, self.lasty = evt.GetPosition()


        def OnMouseUp(self, evt):
            
            self.ReleaseMouse()


        def OnMouseMotion(self, evt):
            
            if evt.Dragging() and evt.LeftIsDown():
                self.lastx, self.lasty = self.x, self.y
                self.x, self.y = evt.GetPosition()
                self.Refresh(False)


    class CubeCanvas(MyCanvasBase):
        
        def InitGL(self):
            
            # set viewing projection
            glMatrixMode(GL_PROJECTION)
            glFrustum(-0.5, 0.5, -0.5, 0.5, 1.0, 3.0)

            # position viewer
            glMatrixMode(GL_MODELVIEW)
            glTranslatef(0.0, 0.0, -2.0)

            # position object
            glRotatef(self.y, 1.0, 0.0, 0.0)
            glRotatef(self.x, 0.0, 1.0, 0.0)

            glEnable(GL_DEPTH_TEST)
            glEnable(GL_LIGHTING)
            glEnable(GL_LIGHT0)


        def OnDraw(self):
            
            # clear color and depth buffers
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

            # draw six faces of a cube
            glBegin(GL_QUADS)
            glNormal3f( 0.0, 0.0, 1.0)
            glVertex3f( 0.5, 0.5, 0.5)
            glVertex3f(-0.5, 0.5, 0.5)
            glVertex3f(-0.5,-0.5, 0.5)
            glVertex3f( 0.5,-0.5, 0.5)

            glNormal3f( 0.0, 0.0,-1.0)
            glVertex3f(-0.5,-0.5,-0.5)
            glVertex3f(-0.5, 0.5,-0.5)
            glVertex3f( 0.5, 0.5,-0.5)
            glVertex3f( 0.5,-0.5,-0.5)

            glNormal3f( 0.0, 1.0, 0.0)
            glVertex3f( 0.5, 0.5, 0.5)
            glVertex3f( 0.5, 0.5,-0.5)
            glVertex3f(-0.5, 0.5,-0.5)
            glVertex3f(-0.5, 0.5, 0.5)

            glNormal3f( 0.0,-1.0, 0.0)
            glVertex3f(-0.5,-0.5,-0.5)
            glVertex3f( 0.5,-0.5,-0.5)
            glVertex3f( 0.5,-0.5, 0.5)
            glVertex3f(-0.5,-0.5, 0.5)

            glNormal3f( 1.0, 0.0, 0.0)
            glVertex3f( 0.5, 0.5, 0.5)
            glVertex3f( 0.5,-0.5, 0.5)
            glVertex3f( 0.5,-0.5,-0.5)
            glVertex3f( 0.5, 0.5,-0.5)

            glNormal3f(-1.0, 0.0, 0.0)
            glVertex3f(-0.5,-0.5,-0.5)
            glVertex3f(-0.5,-0.5, 0.5)
            glVertex3f(-0.5, 0.5, 0.5)
            glVertex3f(-0.5, 0.5,-0.5)
            glEnd()

            if self.size is None:
                self.size = self.GetClientSize()
            w, h = self.size
            w = max(w, 1.0)
            h = max(h, 1.0)
            xScale = 180.0 / w
            yScale = 180.0 / h
            glRotatef((self.y - self.lasty) * yScale, 1.0, 0.0, 0.0);
            glRotatef((self.x - self.lastx) * xScale, 0.0, 1.0, 0.0);

            self.SwapBuffers()


    app = wx.App(0)

    frame = wx.Frame(None, -1, size=(400,400))
    canvas = CubeCanvas(frame)
    frame.Show(True)

    app.MainLoop()

|


Module API
==========

Widgets
^^^^^^^

.. toctree::
   :maxdepth: 1
   :glob:
 
   wx.glcanvas.*