Logo3D

3D Logo interpreter in Python using OpenGL

Setup

Read this entire section before you start running pip commands!

This Python program uses PyGame and openGL and was written and tested in Windows. PyGame can be installed easily enough with pip:

pip install pygame

In theory, it should also be possible to install openGL with pip:

pip install PyOpenGL PyOpenGL_accelerate

...but, this didn't work for me, and glancing at the similar number of problems I found on Google, it also doesn't work for a lot of users on Windows. According to several threads on Stack Overflow the easiest solution is to first remove PyOpenGL if you did run the previous commands:

pip uninstall PyOpenGL PyOpenGL_accelerate

...then visit Christoph Gohlke's website and download the appropriate .whl files for your Python version and OS. Since I am using Python 3.7 on Windows x86 I needed to download PyOpenGL_accelerate-3.1.5-cp37-cp37m-win_amd64.whl and PyOpenGL-3.1.5-cp37-cp37m-win_amd64.whl which could then be installed with the following:

pip install PyOpenGL_accelerate-3.1.5-cp37-cp37m-win_amd64.whl --force-reinstall
pip install PyOpenGL-3.1.5-cp37-cp37m-win_amd64.whl --force-reinstall

Running

Once your environment is setup correctly, you should be able to run the main Logo3D.py file from your terminal:

c:\>python Logo3D.py
python Logo3D.py source-file [options]
       [options] - /d         (debug mode)
       [options] - /r a:x:y:z (rotate at angle 'a' around '(x,y,z)')
                              (defaults to 1:1:1:1)

e.g. python Logo3D.py cude.lgo

The first parameter should be a Logo source code file.

The /d parameter can be used to specify debug-mode, and will cause the program to output additional information during the tokenising, parsing and executing phases. If your Logo script doesn't run, try enabling this flag to see where the syntax error is.

The /r parameter can be used to specify rotation angle a around the location (x,y,z) for performing rotations once the 3D model has been rendered.

Logo Commands

The program supports the following commands:

Command	Meaning
FD X	Move turtle forward X units
BK X	Move turtle forward X units
RT D	Turn turtle right D degrees
LT D	Turn turtle left D degrees
UT D	Turn turtle up D degrees
DT D	Turn turtle down D degrees
PENUP	Lift pen
PENDOWN	Drop pen
HOME	Return turtle to (0, 0, 0)
REPEAT N [ Commands ]	Repeat set of commands N times

So, for example, we can draw a square with the following:

FD 3 RT 90
FD 3 RT 90
FD 3 RT 90
FD 3 RT 90

We can be smarter and use a REPEAT loop:

REPEAT 4 [
    FD 3
    RT 90  
]

Both programs will produce an image that looks like this:

We can use move in all three dimensions by adding the UT or DT commands:

FD 2 UT 90
FD 2 UT 90
FD 2 LT 90
FD 2 LT 90
FD 2 UT 90
FD 2 UT 90
FD 2 RT 90
FD 2

The above program will draw the partial outline of a cube:

Once we have our 3D image rendered we can use the ←, →, ↑ and ↓ buttons on our keyboard to pan, - and = to zoom in and out, and space to toggle rotation:

To exit, press ESC