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Description:

pythoncg 0.1.3

What is python-cg?
python-cg is a Python wrapper for
NVidia Cg Toolkit runtime. I’ve started it because I like Python, I like NVidia CG and I want to to do some computer game/3d graphicsprototyping and research. Also I still find C++ counterproductive as far as my needs are concerned and I don’t want to waste my time doing boring stuff. Programming in Python is fun.
I know about some projects that were meant to bring CG to Python but as far as I know they’re history now.
Project is hostead at GitHub: https://github.com/jstasiak/python-cg.

What’s the state?
The project is in very early development stage. Overview of what’s supported right now:

Cg contexts

creating
destroying

CgFX effects

creating from file
creating directly from source code

accessing effects` techniques and their passes
accessing effect parameters with their names, semantics and parameter-specific metadata (rows, columns etc.)
setting sampler parameters and most of numerical parameters

What doesn’t work at the moment and there’s no plan to implement it:

everything that’s left (well, until I decide I need some of it or someone else does that)

Requirements
This project requires:

NVidia Cg Toolkit ≥ 3.0
Python interpreter (+ development files):

2.x ≥ 2.6, or
3.x ≥ 3.2

C and C++ compiler

Python packages required to build and install python-cg:

Cython ≥ 0.18
numpy

To build documentation/run tests you also need:

Mock ≥ 1.0
Nose ≥ 1.2
Sphinx ~ 1.2 (development version)

Documentation
Pregenerated documentation can be found at https://python-cg.readthedocs.org/en/latest/.
You can also build documentation all by yourself by calling:
sphinx-build -b html docs docs/build/html
Generated HTML files are placed in docs/build/html/ directory.

Building
To build the project in place, run:
python setup.py build_ext --inplace

Important information

This project works with OpenGL and OpenGL only
It uses row-major matrices by default, just like numpy does

Quickstart
First you need to create an instance of
CG class and use it to create new
Context:
from cg import CG

cg = CG()
context = cg.create_context()
We want to use an effect to render some stuff so we’re gonna create
Effect from file:
effect = context.create_effect_from_file('effect.cgfx')

Note
This assumes that you have a file named effect.cgfx and that it contains
a valid CG effect.

We now have access to Effect’s techniques and parameters:
for technique in effect.techniques:
# ...

for parameter in effect.parameters:
# ...
For the sake of simplicity let’s say we have a parameterless effect with only one
Technique:
technique = effect.techniques[0]
Now we can access technique’s passes. Each Pass has methods begin() and end() and the actual
drawing has to take place between a call to begin and end:
gl.glClear(gl.GL_COLOR_BUFFER_BIT)

for pass_ in technique.passes:
pass_.begin()

gl.glBegin(gl.GL_TRIANGLES)
gl.glVertex3f(-0.5, -0.5, 0)
gl.glVertex3f(0.5, -0.5, 0)
gl.glVertex3f(0, 0.5, 0)
gl.glEnd()

pass_.end()

# swap buffers
You can find complete, runnable example application in example directory. Please note that
it requires (in addition to python-cg requirements):

Development version of SFML 2
Python packages listed in example/requirements.txt:
pip install -r example/requirements.txt

Then to run the example:
python setup.py build_ext --inplace
PYTHONPATH=. python example/main.py

Testing
To run tests, execute:
python runtests.py

License
© 2013, Jakub Stasiak
This project is licensed under MIT License, see LICENSE file for details.