# NeHe Tutorial Lesson: 43 - FreeType fonts in OpenGL
#
# Ported to PyOpenGL 2.0 by Brian Leair 18 Jan 2004
#
# This code was created by Jeff Molofee 2000
#
# The port was based on the PyOpenGL tutorials and from
# PyOpenGLContext (tests/glprint.py)
#
# If you've found this code useful, feel free to let me know
# at (Brian Leair telcom_sage@yahoo.com).
#
# See original source and C based tutorial at http://nehe.gamedev.net
#
# Note:
# -----
# This code is not an ideal example of Pythonic coding or use of 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,
# a high quality platform independent library. Due to using these APIs,
# this code is more like a C program using procedural programming.
#
# To run this example you will need:
# Python - www.python.org (v 2.3 as of 1/2004)
# PyOpenGL - pyopengl.sourceforge.net (v 2.0.1.07 as of 1/2004)
# Numeric Python - (v.22 of "numpy" as of 1/2004) numpy.sourceforge.net
# Python Image Library - http://www.pythonware.com/products/pil/ (v1.1.4 or later)
#
# Make sure to get versions of Numeric, PyOpenGL, and PIL to match your
# version of python.
#
#
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
# Imports specific to Lesson 43
import glFreeType
from math import cos
import sys
# Python 2.2 defines these directly
try:
True
except NameError:
True = 1==1
False = 1==0
# 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
our_font = None
# 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.
global our_font
glShadeModel(GL_SMOOTH) # Enables Smooth Color Shading
glClearColor(0.0, 0.0, 0.0, 0.5) # This Will Clear The Background Color To Black
glClearDepth(1.0) # Enables Clearing Of The Depth Buffer
glEnable(GL_DEPTH_TEST) # Enables Depth Testing
glEnable(GL_TEXTURE_2D) # Enables texture mapping
glDepthFunc(GL_LEQUAL) # The Type Of Depth Test To Do
glHint (GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST) # Really Nice Perspective Calculations
# Currently omitting the wgl based font. See lesson13.py for example use of wgl font.
# FYI, the ttf font file "Test.ttf" in lesson43 is the typeface "Arial Black Italic".
# our_font = glFreeType.font_data ("ARBLI___.ttf", 16)
our_font = glFreeType.font_data ("Test.ttf", 16)
return True
# 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()
# // field of view, aspect ratio, near and far
# This will squash and stretch our objects as the window is resized.
gluPerspective(45.0, float(Width)/float(Height), 0.1, 100.0)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
cnt1 = 0
# The main drawing function.
def DrawGLScene():
global cnt1
global our_font
# Clear The Screen And The Depth Buffer
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glLoadIdentity() # Reset The View
# Step back (away from objects)
glTranslatef (0.0, 0.0, -1.0)
# Currently - NYI - No WGL text
# Blue Text
# glColor3ub(0, 0, 0xff)
#
# // Position The WGL Text On The Screen
# glRasterPos2f(-0.40f, 0.35f);
# glPrint("Active WGL Bitmap Text With NeHe - %7.2f", cnt1);
# Red Text
glColor3ub (0xff, 0, 0)
glPushMatrix ()
glLoadIdentity ()
# Spin the text, rotation around z axe == will appears as a 2d rotation of the text on our screen
glRotatef (cnt1, 0, 0, 1)
glScalef (1, 0.8 + 0.3* cos (cnt1/5), 1)
glTranslatef (-180, 0, 0)
our_font.glPrint (320, 240, "Active FreeType Text - %7.2f" % (cnt1))
glPopMatrix ()
# //Uncomment this to test out print's ability to handle newlines.
# our_font.glPrint (320, 240, "Here\nthere\nbe\n\nnewlines %f\n." % (cnt1))
cnt1 += 0.051
# cnt2 += 0.005
glutSwapBuffers()
return
# The function called whenever a key is pressed. Note the use of Python tuples to pass in: (key, x, y)
def keyPressed(*args):
global window
global our_font
# If escape is pressed, kill everything.
if args[0] == ESCAPE:
our_font.release ()
sys.exit()
def main():
global window
# pass arguments to init
glutInit(sys.argv)
# Select type of Display mode:
# Double buffer
# RGBA color
# Alpha components supported
# Depth buffer
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | 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("NeHe & Sven Olsen's TrueType Font Tutorial")
# 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.
if __name__ == "__main__":
print "Hit ESC key to quit."
main()
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