[Mono-osx] [MonoMac] OpenGL OpenTK proposal / compromise

[Geoff Norton]

Kenneth,

  Sure send it to me off-list.

-g

On 2011-02-14, at 2:00 PM, kjpou wrote:

> Geoff
> 
> No problem but have family in town and not sure when I will get to it.  It is looking like next week at the earliest.
> 
> I already have the changes zipped up and can send them to you if you would like.
> 
> Kenneth
> 
> On 2/14/11 6:07 PM, Geoff Norton wrote:
>> Kenneth,
>> 
>>   I'd like to see this code.  I have a opentk repo on github:
>> 
>> http://github.com/kangaroo/opentk
>> 
>> Could you fork it and land your patches?
>> 
>> Thanks
>> 
>> -g
>> 
>> On 2011-02-13, at 9:47 AM, kjpou wrote:
>> 
>>> Hello all
>>> 
>>> Have spent the last two days working on the OpenTK.  Ended in
>>> frustration basically.
>>> 
>>> Here is what I have:
>>> 
>>> OpenTK.Graphics.CoreOpenGL
>>> 
>>> Basically all the mappings, delegates, helper methods, ErrorHelper.  It
>>> was a copy from the windows OpenTK.Graphics.OpenGL.  The bindings are
>>> all there and can load them all from a CglContext which is a new
>>> Platform backend OpenGL context I created.
>>> 
>>> There are something like 2700 method bindings that are delivered with
>>> the Windows OpenGL implementation of which only about 600 are used on
>>> the mac.
>>> 
>>> I have a platform backend hacked together.  When I say hacked I mean
>>> hacked but it all loads fine.  No GUI implementation as it uses the
>>> current context created from NSOpenGLContext.  That part works.
>>> 
>>> OpenTK.Platform.MacOS
>>> 
>>> ->  CocoaBindings
>>> --->  Cgl
>>> 
>>> ->  CglContext
>>> ->  CocoaApplication
>>> ->  CocoaGLNative
>>> ->  CocoaWindowInfo
>>> 
>>> You can create a context.
>>> 
>>>                         OpenTK.Platform.IWindowInfo windowInfo
>>>                                 =
>>> OpenTK.Platform.Utilities.CreateMacOSCocoaWindowInfo( mGLContext.Handle );
>>> 
>>>                         OpenTK.ContextHandle handle = new
>>> OpenTK.ContextHandle( mGLContext.Handle );
>>> 
>>>                         OpenTK.Graphics.GraphicsContext context =
>>>                                 new
>>> OpenTK.Graphics.GraphicsContext(handle, windowInfo);
>>> 
>>>                        context.MakeCurrent( windowInfo );
>>> 
>>> When it starts calling the Delegates for example.
>>> 
>>>                         ErrorCode theError = ErrorCode.NoError;
>>>                         theError = GL.GetError ();
>>>                         GL.ReadBuffer (ReadBufferMode.Front);
>>> 
>>> It is erroring out with errors for the native bindings which I can not
>>> figure out because of the all the Delegate calls.  If you call the
>>> GLCore methods directly it all works fine but using the OpenTK Delegate
>>> way it is not working.
>>> 
>>> If someone wants to take what I have and try to get it all working you
>>> are more than welcome.  Either way those 600 +/- OpenGL calls are going
>>> to have to be gone through and culled out.
>>> 
>>> In about one hour I ripped all the mappings from the OpenTK for Cocoa
>>> that I wrote and placed them in a separate project with some small
>>> modifications and got two MonoMac OpenGL samples working.  One hour vs
>>> two days hummmm really a no brainer there for where I would prefer to
>>> spend my time.
>>> 
>>> I am in the process of going through by hand and only implementing those
>>> 600 or so methods by hand to get a MonoMac.CoreOpenGL bindings working
>>> based on that one hours work.  Basing it on what I learned from the
>>> OpenTK I can have it mapping exactly the same way so if someone gets the
>>> OpenTK working it should be just a change of library.  What I mean by
>>> that is that all one would have to do to use the OpenTK is include it in
>>> the project because the naming of the parameters will be exactly the
>>> same as those you will already be using for the MonoMac.CoreOpenGL bindings.
>>> 
>>> So the following code below would work with OpenTK as well as the
>>> MonoMac.CoreOpenGL bindings.  Technically the same code would work for
>>> any other OpenTK based program as well.
>>> 
>>>                         ErrorCode theError = ErrorCode.NoError;
>>> 
>>>                         // select front buffer as our source for pixel data
>>>                         GL.ReadBuffer (ReadBufferMode.Front);
>>> 
>>>                         //Read OpenGL context pixels directly.
>>> 
>>>                         // For extra safety, save&  restore OpenGL
>>> states that are changed
>>>                         GL.PushClientAttrib
>>> (ClientAttribMask.ClientPixelStoreBit);
>>> 
>>>                         GL.PixelStore
>>> (PixelStoreParameter.PackAlignment, 4); /* Force 4-byte alignment */
>>>                         GL.PixelStore
>>> (PixelStoreParameter.PackRowLength, 0);
>>>                         GL.PixelStore
>>> (PixelStoreParameter.PackSkipRows, 0);
>>>                         GL.PixelStore
>>> (PixelStoreParameter.PackSkipPixels, 0);
>>>                         // Read a block of pixels from the frame buffer
>>>                         GL.ReadPixels (0, 0, bufferWidth, bufferHeight,
>>> PixelFormat.Bgra, PixelType.UnsignedInt8888Reversed, buffer);
>>> 
>>>                         GL.PopClientAttrib ();
>>> 
>>>                         theError = GL.GetError ();
>>>                         if (theError != ErrorCode.NoError)
>>>                                 Console.WriteLine ("OpenGL error {0}",
>>> theError);
>>> 
>>> 
>>> Now before I go through with this would like to know if this is an
>>> acceptable compromise and would it be worth the effort to be included
>>> within the MonoMac bindings.
>>> 
>>> If you want the code that I have begun for OpenTK let me know.
>>> 
>>> Kenneth
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> _______________________________________________
>>> Mono-osx mailing list
>>> Mono-osx at lists.ximian.com
>>> http://lists.ximian.com/mailman/listinfo/mono-osx
>>