joi, 11 martie 2010

PyGame and OpenGL - part 2

Today i will show you how we find stuff about graphic hardware.
We will use two modules: pyopengl and pygame.
Modules can import other modules.
Each module is only imported once per interpreter session.
>>> import pygame 
>>> import OpenGL 

The imports are taken in the local symbol table, so we need to do this:
>>> from pygame import *
>>> from OpenGL import *
>>> from OpenGL.GL import * 
>>> from OpenGL.GLUT import * 

The next thing you must do is call the function glutInit.
>>> glutInit()
['foo']

And now use pygame to create window.
>>> pygame.init()
(6, 0)
>>> pygame.display.set_mode((10,10),OPENGL|DOUBLEBUF)


Note:If we not create the window the next commands will not work.
About the beautiful glGetString function, we know.
This return a string describing the current GL connection.
You can use dir() and help() functions to see more.
But we see bellow, some example:
>>> dir(glGetString)
['__call__', '__class__', '__ctypes_from_outparam__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__name__', '__new__', '__nonzero__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setstate__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_b_base_', '_b_needsfree_', '_flags_', '_objects', '_restype_', 'argtypes', 'errcheck', 'restype']
>>> dir(glGetString())
['__class__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__']

Now, the parameters of this function are :
glGetString(GL_VERSION)
glGetString(GL_VENDOR)
glGetString(GL_RENDERER)
glGetStringi(GL_EXTENSIONS, i) 

Bellow, we see how we use these parameters:
>>> glGetString(GL_VERSION) 
'2.1.2 NVIDIA 173.14.22'
>>> glGetString(GL_VENDOR) 
'NVIDIA Corporation'
>>> glGetString(GL_RENDERER) 
'GeForce FX 5200/AGP/SSE/3DNOW!'

Because the GL_EXTENSIONS is a space-separated list of supported extensions to GL, we can use these commands:
>>> print glGetString(GL_EXTENSIONS)

Or you can format this result, see bellow
>>> print glGetString(GL_EXTENSIONS).split()
['GL_ARB_depth_texture', 'GL_ARB_fragment_program', ...

This is all.