pyglfw 0.1.0

Python bindings for the GLFW library

Python bindings for the GLFW library.

Home: https://bitbucket.org/pyglfw/pyglfw

Introduction

At the moment of development there were already available numerous variants of bindings for the glfw library to python. Besides driving by NIH syndrome these binding were developed with following assumptions in mind:

• Compatibility with GLFW version 3 and higher api.

• Support for both Python2 (2.7) and Python3 (3.3+).

• Provide low-level and pythonic api separately.

• No external dependencies. Thus using ctypes.

Platforms

During development these bindings were proven to work on all major operating systems environments including Windows, OSX and Linux.

CPython implementations were tested against versions of Python 2.7 and Python 3.3 with no serious issues found.

By the way testing was performed with PyPy. As a result there were revealed issue with ctypes implemenation in PyPy. Issue was fixed and should be available as a part of PyPy 2.2.2.

Licensing

These bindings are distributed under the terms and conditions of zlib license with the exception to files in examples folder which are provided with no limitations to use. Full text of license with copyright notice is provided in the LICENSE file.

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Installation

Ensure you’ve installed GLFW shared library binary according to instructions on project’s page related to installed operating system.

At the moment these binding could be installed with provided setup.py script. To do this retrieve sources either cloning repository or downloading and unpacking source archive. Following commands depend on system used.

On Linux and OSX

$ python ./setup.py sdist

then

# easy_install dist/pyglfw-<ver>.tar.gz

or

# pip install dist/pyglfw-<ver>.tar.gz

On Windows

> python.exe setup.py bdist_wininst

then run exe installer from dist folder.

NOTE: Prebuilt exe installers could be found on the project’s home download page

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Libapi

Low-level libapi package serves as thin wrapper above GLFW library. It’s api mostly resemble one of C library except functions that require pass-by-ref parameters. As a rule of thumb all functions that return void and fill several values via pass-by-ref parameters are mapped to functions returning tuple of values. And functions that return pointer to array with number of items set via pass-by-ref parameter are mapped to functions returning list of items. I.e.:

int major, minor, rev;
glfwGetVersion(&major, &minor, &rev)

becomes

major, minor, rev = glfwGetVersion()

and

int n_items;
GLFWmonitor **monitors = glfwGetMonitors(&n_items)

becomes

monitors = glfwGetMonitors()

Special note should be done regarding window pointer functions. glfwSetWindowPointer allows to set any python object as a window private data and retrieve it back with glfwGetWindowPointer. However it’s still required to hold reference to this object in python code. Also this functionality will not work with PyPy implemetation due to lack of py_object support.

The requirement to hold references also spreads to functions that are settings varios callbacks. Please refer to raw_api in examples for usage primer.

Pyglfw

Pythonic pyglfw package handles following moments:

• Encapsulation of struct pointers and functions api into objects with properties and methods.

• Transparent usage of strings (either from python 2 or from python 3).

• Raising exceptions in case of errors.

• Eliminates need to use of ctypes structures and ctypes-based callback prototypes.

• Holds references for set to callback functions, so there is no need to hold them outside.

• Provide pythonic types for callback functions.

and following functionality is restricted:

• No get/set window pointers. Due to its ambiquity.

• No set error callback. Error callback is used to raise exeptions.

• Set callback methods doesn’t return previously used callback. It’s unable to certainly map them to python object in every case.

• No check for extensions and proc address query. This should be handled with dedicated frameworks like PyOpenGL.

Side-by-Side

Here is side-by-side comparison of same operations performed via low-level (libapi) and pythonic (pyglfw) bindings.

Basics

libapi:

from pyglfw.libapi import *

glfwInit()

glfwGetVersion()

glfwTerminate()

glfwPollEvents()

pyglfw:

import pyglfw.pyglfw as glfw

glfw.init()

glfw.api_version()

glfw.terminate()

glfw.poll_events()

Monitors

libapi:

monitorp = glfwGetPrimaryMonitor()

curmode = glfwGetVideoMode(monitorp)

allmodes = glfwGetVideoModes(monitorp)

@GLFWmonitorfun
def on_monitor_event(monitor, event):
    if event == GLFW_CONNECTED:
        print(glfwGetMonitorName(monitor))

glfwSetMonitorCallback(on_monitor_event)

pyglfw:

monitor = glfw.get_primary_monitor()

curmore = monitor.video_mode

allmodes = monitor.video_modes

def on_monitor_event(monitor, event):
    if event == glfw.Monitor.CONNECTED:
        print(monitor.name)

glfw.Monitor.set_callback(on_monitor_event)

Hints

libapi:

glfwDefaultWindowHints()

glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_API)

w, h = curmode.width, curmode.height
windowp = glfwCreateWindow(w, h, b'libapi', None, None)

glfwDestroyWindow(windowp)

pyglfw:

glfw.Window.hint()

glfw.Window.hint(client_api=glfw.Window.OPENGL_API)

w, h = curmode.width, curmode.height
window = glfw.Window(w, h, 'pyglfw')

window.close()

Swap

libapi:

context = glfwGetCurrentContext()

glfwMakeContextCurrent(windowp)

glfwSwapInterval(0)

glfwMakeContextCurrent(context)

glfwMakeContextCurrent(windowp)

glfwSwapBuffers(windowp)

pyglfw:

# makes context current
# and restores previous
window.swap_interval(0)

window.make_current()

window.swap_buffers()

Windows

libapi:

if not glfwWindowShouldClose():
    glfwSetWindowTitle(b'libapi')

    size = glfwGetWindowSize()

    glfwShowWindow()

is_visible = glfwGetWindowAttrib(GLFW_VISIBLE)

client_api = glfwGetWindowAttrib(GLFW_CLIENT_API)

glfwSetWindowAttrib(GLFW_FOCUSED, 1)

@GLFWwindowsizefun
def on_window_size(windowp, w, h):
    glfwSetWindowSize(windowp, size[0], size[1])

glfwSetWindowSizeCallback(windowp, on_window_size)

pyglfw:

if not window.should_close:
    window.set_title('pyglfw')

    size = window.size

    window.show()

is_visible = window.visible

client_api = window.client_api

window.has_focus = True

def on_window_size(window, w, h):
    window.size = size

window.set_window_size_callback(on_window_size)

Inputs

libapi:

mode = glfwGetInputMode(windowp, GLFW_STICKY_KEYS)

glfwSetInputMode(windowp, GLFW_STICKY_MOUSE_BUTTONS, mode)

is_escape = glfwGetKey(windowp, GLFW_ESCAPE)

is_middle = glfwGetMouseButton(windowp, GLFW_MOUSE_BUTTON_MIDDLE)

cursor_at = glfwGetCursorPos(windowp)

@GLFWkeyfun
def on_key(windowp, key, scancode, action, mods):
    if key == GLFW_ESCAPE:
        glfwSetWindowShouldClose(1)

glfwSetKeyCallback(windowp, on_key)

if glfwJoystickPresent(0):
    joy_name = glfwGetJoystickName(0)
    joy_axes = glfwGetJoystickAxes(0)

pyglfw:

mode = window.sticky_keys

window.sticky_mice = mode

is_escape = window.keys.escape

is_middle = window.mice.middle

cursor_at = window.cursor_pos

def on_key(window, key, scancode, action, mods):
    if key == glfw.Keys.ESCAPE:
        window.should_close = True

window.set_key_callback(on_key)

js = glfw.Joystick(0)

if js:
    joy_name = js.name
    joy_axes = js.axes