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

[kjpou]

Geoff

Sent the files to you off list.  Let me know if you have any questions.

I will be out from tomorrow until monday unless I find internet access.

Kenneth

On 2/14/11 9:28 PM, Geoff Norton wrote:
> 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
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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>