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#!
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# This is statement is required by the build system to query build info
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if __name__ == '__build__':
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        raise Exception
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import string
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__version__ = string.split('$Revision: 1.1.1.1 $')[1]
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__date__ = string.join(string.split('$Date: 2007/02/15 19:25:20 $')[1:3], ' ')
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__author__ = 'Tarn Weisner Burton <twburton@users.sourceforge.net>'
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#
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# Ported to PyOpenGL 2.0 by Tarn Weisner Burton 10May2001
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#
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# This code was created by Richard Campbell '99 (ported to Python/PyOpenGL by John Ferguson 2000)
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#
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# The port was based on the PyOpenGL tutorial module: dots.py  
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#
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# If you've found this code useful, please let me know (email John Ferguson at hakuin@voicenet.com).
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#
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# See original source and C based tutorial at http://nehe.gamedev.net
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#
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# Note:
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# -----
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# This code is not a good example of Python and using OO techniques.  It is a simple and direct
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# exposition of how to use the Open GL API in Python via the PyOpenGL package.  It also uses GLUT,
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# which in my opinion is a high quality library in that it makes my work simpler.  Due to using
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# these APIs, this code is more like a C program using function based programming (which Python
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# is in fact based upon, note the use of closures and lambda) than a "good" OO program.
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#
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# To run this code get and install OpenGL, GLUT, PyOpenGL (see http://www.python.org), and PyNumeric.
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# Installing PyNumeric means having a C compiler that is configured properly, or so I found.  For 
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# Win32 this assumes VC++, I poked through the setup.py for Numeric, and chased through disutils code
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# and noticed what seemed to be hard coded preferences for VC++ in the case of a Win32 OS.  However,
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# I am new to Python and know little about disutils, so I may just be not using it right.
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#
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# BTW, since this is Python make sure you use tabs or spaces to indent, I had numerous problems since I 
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# was using editors that were not sensitive to Python.
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#
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from OpenGL.GL import *
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from OpenGL.GLUT import *
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from OpenGL.GLU import *
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import sys
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# Some api in the chain is translating the keystrokes to this octal string
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# so instead of saying: ESCAPE = 27, we use the following.
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ESCAPE = '\033'
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# Number of the glut window.
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window = 0
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# A general OpenGL initialization function.  Sets all of the initial parameters. 
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def InitGL(Width, Height):                                # We call this right after our OpenGL window is created.
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    glClearColor(0.0, 0.0, 0.0, 0.0)        # This Will Clear The Background Color To Black
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    glClearDepth(1.0)                                        # Enables Clearing Of The Depth Buffer
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    glDepthFunc(GL_LESS)                                # The Type Of Depth Test To Do
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    glEnable(GL_DEPTH_TEST)                                # Enables Depth Testing
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    glShadeModel(GL_SMOOTH)                                # Enables Smooth Color Shading
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    glMatrixMode(GL_PROJECTION)
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    glLoadIdentity()                                        # Reset The Projection Matrix
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                                                                                # Calculate The Aspect Ratio Of The Window
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    gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)
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    glMatrixMode(GL_MODELVIEW)
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# The function called when our window is resized (which shouldn't happen if you enable fullscreen, below)
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def ReSizeGLScene(Width, Height):
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    if Height == 0:                                                # Prevent A Divide By Zero If The Window Is Too Small 
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            Height = 1
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    glViewport(0, 0, Width, Height)                # Reset The Current Viewport And Perspective Transformation
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    glMatrixMode(GL_PROJECTION)
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    glLoadIdentity()
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    gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)
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    glMatrixMode(GL_MODELVIEW)
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# The main drawing function. 
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def DrawGLScene():
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        # Clear The Screen And The Depth Buffer
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        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
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        glLoadIdentity()                                        # Reset The View 
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        # Move Left 1.5 units and into the screen 6.0 units.
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        glTranslatef(-1.5, 0.0, -6.0)
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        # Draw a triangle
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        glBegin(GL_POLYGON)                 # Start drawing a polygon
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        glVertex3f(0.0, 1.0, 0.0)           # Top
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        glVertex3f(1.0, -1.0, 0.0)          # Bottom Right
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        glVertex3f(-1.0, -1.0, 0.0)         # Bottom Left
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        glEnd()                             # We are done with the polygon
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        # Move Right 3.0 units.
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        glTranslatef(3.0, 0.0, 0.0)
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        # Draw a square (quadrilateral)
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        glBegin(GL_QUADS)                   # Start drawing a 4 sided polygon
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        glVertex3f(-1.0, 1.0, 0.0)          # Top Left
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        glVertex3f(1.0, 1.0, 0.0)           # Top Right
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        glVertex3f(1.0, -1.0, 0.0)          # Bottom Right
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        glVertex3f(-1.0, -1.0, 0.0)         # Bottom Left
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        glEnd()                             # We are done with the polygon
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        #  since this is double buffered, swap the buffers to display what just got drawn. 
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        glutSwapBuffers()
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# The function called whenever a key is pressed. Note the use of Python tuples to pass in: (key, x, y)  
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def keyPressed(*args):
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        # If escape is pressed, kill everything.
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    if args[0] == ESCAPE:
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            sys.exit()
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def main():
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        global window
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        # For now we just pass glutInit one empty argument. I wasn't sure what should or could be passed in (tuple, list, ...)
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        # Once I find out the right stuff based on reading the PyOpenGL source, I'll address this.
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        glutInit(sys.argv)
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        # Select type of Display mode:   
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        #  Double buffer 
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        #  RGBA color
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        # Alpha components supported 
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        # Depth buffer
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        glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
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        # get a 640 x 480 window 
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        glutInitWindowSize(640, 480)
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        # the window starts at the upper left corner of the screen 
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        glutInitWindowPosition(0, 0)
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        # Okay, like the C version we retain the window id to use when closing, but for those of you new
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        # to Python (like myself), remember this assignment would make the variable local and not global
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        # if it weren't for the global declaration at the start of main.
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        window = glutCreateWindow("Jeff Molofee's GL Code Tutorial ... NeHe '99")
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           # Register the drawing function with glut, BUT in Python land, at least using PyOpenGL, we need to
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        # set the function pointer and invoke a function to actually register the callback, otherwise it
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        # would be very much like the C version of the code.        
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        glutDisplayFunc(DrawGLScene)
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        # Uncomment this line to get full screen.
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        #glutFullScreen()
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        # When we are doing nothing, redraw the scene.
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        glutIdleFunc(DrawGLScene)
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        # Register the function called when our window is resized.
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        glutReshapeFunc(ReSizeGLScene)
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        # Register the function called when the keyboard is pressed.  
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        glutKeyboardFunc(keyPressed)
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        # Initialize our window. 
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        InitGL(640, 480)
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        # Start Event Processing Engine        
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        glutMainLoop()
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# Print message to console, and kick off the main to get it rolling.
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print "Hit ESC key to quit."
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main()
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