[PyQt] Creating a projection matrix in Qt OpenGL

alan moore me at alandmoore.com
Wed Mar 20 03:42:23 GMT 2019

I'm working on a small demo of OpenGL in PyQt using the QOpenGLWidget.

My demo works except that whenever I translate it with a negative Z, the 
back side of the drawing is getting cut off.  It seems like I must not 
be setting the projection matrix correctly.

Below is my overridden resizeGL() method that sets up the matrix.  Am I 
doing this correctly?

     def resizeGL(self, width, height):
         super().resizeGL(width, height)
         self.gl.glViewport(0, 0, self.width(), self.height())
         near_plane = 1
         far_plane = 200
         angle = 45
         aspect = self.width() / self.height()
         self.projection = qtg.QMatrix4x4()
             angle, aspect, near_plane, far_plane)

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