OpenGLDemo
==========

* :download:`Download example <PyObjCExample-OpenGLDemo.zip>`

OpenGLDemo

OpenGLDemo is probably the simplest possible demonstration of
using OpenGL from a PyObjC application.  It is a port of Apple's
"CocoaGL" example.  Note that this requires PyOpenGL to be installed.

See:    /Developer/Examples/OpenGL/Cocoa/CocoaGL
        http://pyopengl.sourceforge.net/

The source of this application demonstrates
- Using PyOpenGL from Cocoa

Bob Ippolito
bob@redivi.com


.. rst-class:: tabber

Sources
-------

.. rst-class:: tabbertab

OpenGLDemo.py
.............

.. sourcecode:: python

    """OpenGLDemo.py -- A simple demo of using OpenGL with Cocoa
    
    To build the demo program, run this line in Terminal.app:
    
        $ python setup.py py2app -A
    
    This creates a directory "dist" containing OpenGLDemo.app. (The
    -A option causes the files to be symlinked to the .app bundle instead
    of copied. This means you don't have to rebuild the app if you edit the
    sources or nibs.)
    
    This example requires PyOpenGL
    """
    
    from Cocoa import (
        NSOpenGLView,
        NSOpenGLPFANoRecovery,
        NSOpenGLPFAWindow,
        NSOpenGLPFAAccelerated,
        NSOpenGLPFADoubleBuffer,
        NSOpenGLPFAColorSize,
        NSOpenGLPFAAlphaSize,
        NSOpenGLPFADepthSize,
        NSOpenGLPFAStencilSize,
        NSOpenGLPFAAccumSize,
        NSOpenGLPixelFormat,
    )
    from OpenGL.GL import (
        glViewport,
        glClearColor,
        glClear,
        GL_COLOR_BUFFER_BIT,
        GL_DEPTH_BUFFER_BIT,
        GL_STENCIL_BUFFER_BIT,
    )
    from PyObjCTools import AppHelper
    import objc
    from objc import super
    
    ClearColors = redIndex, greenIndex, blueIndex, alphaIndex = range(4)
    
    
    class OpenGLDemoView(NSOpenGLView):
        def awakeFromNib(self):
            self.color_index = alphaIndex
    
        def initWithFrame_(self, frame):
            attribs = [
                NSOpenGLPFANoRecovery,
                NSOpenGLPFAWindow,
                NSOpenGLPFAAccelerated,
                NSOpenGLPFADoubleBuffer,
                NSOpenGLPFAColorSize,
                24,
                NSOpenGLPFAAlphaSize,
                8,
                NSOpenGLPFADepthSize,
                24,
                NSOpenGLPFAStencilSize,
                8,
                NSOpenGLPFAAccumSize,
                0,
            ]
            fmt = NSOpenGLPixelFormat.alloc().initWithAttributes_(attribs)
            self = super(OpenGLDemoView, self).initWithFrame_pixelFormat_(frame, fmt)
            return self
    
        @objc.IBAction
        def setClearColor_(self, sender):
            self.color_index = sender.tag()
            self.setNeedsDisplay_(True)
    
        def drawRect_(self, pos, siz):
            x, y = pos
            w, h = siz
            glViewport(0, 0, w, h)
            clear_color = [0.0] * 4
            clear_color[self.color_index] = 1.0
            glClearColor(*clear_color)
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT)
            self.openGLContext().flushBuffer()
    
    
    if __name__ == "__main__":
        AppHelper.runEventLoop()

.. rst-class:: tabbertab

setup.py
........

.. sourcecode:: python

    """
    Script for building the example.
    
    Usage:
        python3 setup.py py2app
    """
    from setuptools import setup
    
    plist = {"NSMainNibFile": "OpenGLDemo"}
    setup(
        name="OpenGLDemo",
        app=["OpenGLDemo.py"],
        data_files=["OpenGLDemo.nib"],
        options={"py2app": {"plist": plist}},
        setup_requires=["py2app", "PyOpenGL", "pyobjc-framework-Cocoa"],
    )

