AVFoundation: render camera frames using OpenGL textures on iOS.

OpenGL textures can easily be created from a CVImageBuffer using
Apple APIs. It avoids having to map the buffer to main memory and
therefore greatly improves rendering performances.

We could do the same on OSX, but there, the textures are always of
the GL_TEXTURE_RECTANGLE target type and changes need to be
done to the QVideoFrame API and to the video node implementations
to support that.

Change-Id: I6dde7e8d7a27460e41523cd474c3c741affc1480
Reviewed-by: James Turner <james.turner@kdab.com>
Reviewed-by: Christian Stromme <christian.stromme@theqtcompany.com>

1 files changed, 19 insertions, 12 deletions

diff --git a/src/plugins/avfoundation/camera/avfcameraviewfindersettingscontrol.mm b/src/plugins/avfoundation/camera/avfcameraviewfindersettingscontrol.mm
index b32c0cd63..05f28898d 100644
--- a/src/plugins/avfoundation/camera/avfcameraviewfindersettingscontrol.mm
+++ b/src/plugins/avfoundation/camera/avfcameraviewfindersettingscontrol.mm
@@ -573,22 +573,29 @@ void AVFCameraViewfinderSettingsControl2::applySettings()
     if (!convertPixelFormatIfSupported(m_settings.pixelFormat(), avfPixelFormat)) {
         // If the the pixel format is not specified or invalid, pick the preferred video surface
         // format, or if no surface is set, the preferred capture device format
-        const QVector<QVideoFrame::PixelFormat> deviceFormats = viewfinderPixelFormats();
-        QList<QVideoFrame::PixelFormat> surfaceFormats;
-        if (m_service->videoOutput() && m_service->videoOutput()->surface())
-            surfaceFormats = m_service->videoOutput()->surface()->supportedPixelFormats();
-
-        QVideoFrame::PixelFormat format = deviceFormats.first();
 
-        for (int i = 0; i < surfaceFormats.count(); ++i) {
-            const QVideoFrame::PixelFormat surfaceFormat = surfaceFormats.at(i);
-            if (deviceFormats.contains(surfaceFormat)) {
-                format = surfaceFormat;
-                break;
+        const QVector<QVideoFrame::PixelFormat> deviceFormats = viewfinderPixelFormats();
+        QVideoFrame::PixelFormat pickedFormat = deviceFormats.first();
+
+        QAbstractVideoSurface *surface = m_service->videoOutput() ? m_service->videoOutput()->surface()
+                                                                  : 0;
+        if (surface) {
+            if (m_service->videoOutput()->supportsTextures()) {
+                pickedFormat = QVideoFrame::Format_ARGB32;
+            } else {
+                QList<QVideoFrame::PixelFormat> surfaceFormats = m_service->videoOutput()->surface()->supportedPixelFormats();
+
+                for (int i = 0; i < surfaceFormats.count(); ++i) {
+                    const QVideoFrame::PixelFormat surfaceFormat = surfaceFormats.at(i);
+                    if (deviceFormats.contains(surfaceFormat)) {
+                        pickedFormat = surfaceFormat;
+                        break;
+                    }
+                }
             }
         }
 
-        CVPixelFormatFromQtFormat(format, avfPixelFormat);
+        CVPixelFormatFromQtFormat(pickedFormat, avfPixelFormat);
     }
 
     if (avfPixelFormat != 0) {