[Development] QTBUG-61258 and Qt3D status

[Morten Sørvig]

Hi,

> On 14 Dec 2018, at 14:07, Massimo Callegari <massimocallegari at yahoo.it> wrote:

> (also cause of broken video playback on core context QTBUG-51064)

I was able to spend some time looking at the related QTBUG-62694, and:

- The fault appears to be that the implementation in  AVFVideoFrameRenderer::renderLayerToFBO() uses the native [CARenderer rendererWithCGLContext] API, which expects that the caller sets up global OpenGL state (projection/modelview matrices). This not supported by the OpenGL Core profiles, and given that OpenGL is deprecated on macOS it is unlikely that we’ll see a new OpenGL API here.

- There is a Metal replacement API: [CARenderer rendererWithMTLTexture] (macOS 10.13+). I was not immediately able to get it to work, but we should be able to produce both OpenGL textures and QImages from the Metal texture (as required by the AVFVideoFrameRenderer API).

So as it stands, QtMultimedia is unfortunately caught up in the OpenGL -> Metal transition and does not support OpenGL Core profiles.

Cheers
Morten