#!
# This is statement is required by the build system to query build info
if __name__ == '__build__':
raise Exception
import string
__version__ = string.split('$Revision: 1.8 $')[1]
__date__ = string.join(string.split('$Date: 2002/12/31 04:13:56 $')[1:3], ' ')
__author__ = 'Tarn Weisner Burton <twburton@users.sourceforge.net>'
#
# Ported to PyOpenGL 2.0 by Tarn Weisner Burton 10May2001
#
# This code was created by Richard Campbell '99 (ported to Python/PyOpenGL by John Ferguson 2000)
#
# The port was based on the PyOpenGL tutorial module: dots.py
#
# If you've found this code useful, please let me know (email John Ferguson at hakuin@voicenet.com).
#
# See original source and C based tutorial at http://nehe.gamedev.net
#
# Note:
# -----
# This code is not a good example of Python and using OO techniques. It is a simple and direct
# exposition of how to use the Open GL API in Python via the PyOpenGL package. It also uses GLUT,
# which in my opinion is a high quality library in that it makes my work simpler. Due to using
# these APIs, this code is more like a C program using function based programming (which Python
# is in fact based upon, note the use of closures and lambda) than a "good" OO program.
#
# To run this code get and install OpenGL, GLUT, PyOpenGL (see http://www.python.org), and NumPy.
# Installing PyNumeric means having a C compiler that is configured properly, or so I found. For
# Win32 this assumes VC++, I poked through the setup.py for Numeric, and chased through disutils code
# and noticed what seemed to be hard coded preferences for VC++ in the case of a Win32 OS. However,
# I am new to Python and know little about disutils, so I may just be not using it right.
#
# NumPy is not a hard requirement, as I am led to believe (based on skimming PyOpenGL sources) that
# PyOpenGL could run without it. However preformance may be impacted since NumPy provides an efficient
# multi-dimensional array type and a linear algebra library.
#
# BTW, since this is Python make sure you use tabs or spaces to indent, I had numerous problems since I
# was using editors that were not sensitive to Python.
#
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import sys
# Some api in the chain is translating the keystrokes to this octal string
# so instead of saying: ESCAPE = 27, we use the following.
ESCAPE = '\033'
# Number of the glut window.
window = 0
# Rotation angle for the triangle.
rtri = 0.0
# Rotation angle for the quadrilateral.
rquad = 0.0
# A general OpenGL initialization function. Sets all of the initial parameters.
def InitGL(Width, Height): # We call this right after our OpenGL window is created.
glClearColor(0.0, 0.0, 0.0, 0.0) # This Will Clear The Background Color To Black
glClearDepth(1.0) # Enables Clearing Of The Depth Buffer
glDepthFunc(GL_LESS) # The Type Of Depth Test To Do
glEnable(GL_DEPTH_TEST) # Enables Depth Testing
glShadeModel(GL_SMOOTH) # Enables Smooth Color Shading
glMatrixMode(GL_PROJECTION)
glLoadIdentity() # Reset The Projection Matrix
# Calculate The Aspect Ratio Of The Window
gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)
glMatrixMode(GL_MODELVIEW)
# The function called when our window is resized (which shouldn't happen if you enable fullscreen, below)
def ReSizeGLScene(Width, Height):
if Height == 0: # Prevent A Divide By Zero If The Window Is Too Small
Height = 1
glViewport(0, 0, Width, Height) # Reset The Current Viewport And Perspective Transformation
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)
glMatrixMode(GL_MODELVIEW)
# The main drawing function.
def DrawGLScene():
global rtri, rquad
# Clear The Screen And The Depth Buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glLoadIdentity() # Reset The View
# Move Left 1.5 units and into the screen 6.0 units.
glTranslatef(-1.5, 0.0, -6.0)
# We have smooth color mode on, this will blend across the vertices.
# Draw a triangle rotated on the Y axis.
glRotatef(rtri, 0.0, 1.0, 0.0) # Rotate
glBegin(GL_POLYGON) # Start drawing a polygon
glColor3f(1.0, 0.0, 0.0) # Red
glVertex3f(0.0, 1.0, 0.0) # Top
glColor3f(0.0, 1.0, 0.0) # Green
glVertex3f(1.0, -1.0, 0.0) # Bottom Right
glColor3f(0.0, 0.0, 1.0) # Blue
glVertex3f(-1.0, -1.0, 0.0) # Bottom Left
glEnd() # We are done with the polygon
# We are "undoing" the rotation so that we may rotate the quad on its own axis.
# We also "undo" the prior translate. This could also have been done using the
# matrix stack.
glLoadIdentity()
# Move Right 1.5 units and into the screen 6.0 units.
glTranslatef(1.5, 0.0, -6.0)
# Draw a square (quadrilateral) rotated on the X axis.
glRotatef(rquad, 1.0, 0.0, 0.0) # Rotate
glColor3f(0.3, 0.5, 1.0) # Bluish shade
glBegin(GL_QUADS) # Start drawing a 4 sided polygon
glVertex3f(-1.0, 1.0, 0.0) # Top Left
glVertex3f(1.0, 1.0, 0.0) # Top Right
glVertex3f(1.0, -1.0, 0.0) # Bottom Right
glVertex3f(-1.0, -1.0, 0.0) # Bottom Left
glEnd() # We are done with the polygon
# What values to use? Well, if you have a FAST machine and a FAST 3D Card, then
# large values make an unpleasant display with flickering and tearing. I found that
# smaller values work better, but this was based on my experience.
rtri = rtri + 1.0 # Increase The Rotation Variable For The Triangle
rquad = rquad - 1.0 # Decrease The Rotation Variable For The Quad
# since this is double buffered, swap the buffers to display what just got drawn.
glutSwapBuffers()
# The function called whenever a key is pressed. Note the use of Python tuples to pass in: (key, x, y)
def keyPressed(*args):
# If escape is pressed, kill everything.
if args[0] == ESCAPE:
sys.exit()
def main():
global window
glutInit(sys.argv)
# Select type of Display mode:
# Double buffer
# RGBA color
# Alpha components supported
# Depth buffer
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
# get a 640 x 480 window
glutInitWindowSize(640, 480)
# the window starts at the upper left corner of the screen
glutInitWindowPosition(0, 0)
# Okay, like the C version we retain the window id to use when closing, but for those of you new
# to Python (like myself), remember this assignment would make the variable local and not global
# if it weren't for the global declaration at the start of main.
window = glutCreateWindow("Jeff Molofee's GL Code Tutorial ... NeHe '99")
# Register the drawing function with glut, BUT in Python land, at least using PyOpenGL, we need to
# set the function pointer and invoke a function to actually register the callback, otherwise it
# would be very much like the C version of the code.
glutDisplayFunc(DrawGLScene)
# Uncomment this line to get full screen.
# glutFullScreen()
# When we are doing nothing, redraw the scene.
glutIdleFunc(DrawGLScene)
# Register the function called when our window is resized.
glutReshapeFunc(ReSizeGLScene)
# Register the function called when the keyboard is pressed.
glutKeyboardFunc(keyPressed)
# Initialize our window.
InitGL(640, 480)
# Start Event Processing Engine
glutMainLoop()
# Print message to console, and kick off the main to get it rolling.
print "Hit ESC key to quit."
main()
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