Develop Reference

HDR gradient on Android not possible?

I am trying to render a smooth gradient from 0% to 10% gray across the screen of Asus Rog Phone 2 which supposedly has an HDR10 screen. In standard (8bit?) rendering mode I can clearly see banding between the gradient levels.
I followed the instructions from Android to modify the Vulkan tutorial sample code in the following way:
Added android:colorMode="wideColorGamut to AndroidManifest.xml.
Changed VkSwapchainCreateInfoKHR.imageFormat, VkAttachmentDescription.format and VkImageViewCreateInfo.format to VK_FORMAT_R16G16B16A16_SFLOAT (everything to setup swapchain).
Changed VkSwapchainCreateInfoKHR.imageColorSpace to VK_COLOR_SPACE_DISPLAY_P3_NONLINEAR_EXT.
I render the gradient dynamically in a custom fragment shader as a function of texturing coordinates mapped to a full-screen quad:
layout (location = 0) in vec2 texcoord;
layout (location = 0) out vec4 uFragColor;
void main() {
uFragColor = vec4(vec3(texcoord.x*0.1), 1.0);
}
As a result I observe absolutely no difference from the original 8bit(?) mode. I am not quite sure how to debug it and what to try.
I also tried to implement the same effect in Unity with HDR options enabled. There I see that all the intermediate rendering passes (in Forward mode) render to Float16 but the last extra pass likely converts it into RGB8. The visual result is the same banding again.
This makes me wonder whether this is not caused by some missing setting. In another thread I saw discussion of Window.setFormat(PixelFormat) or SurfaceHolder.setFormat(PixelFormat) but I am not sure how this related to a Native Android app. I cannot see a way how to call such function and I am not even sure if it would make sense.
Thank you for any suggestions.

Where are you setting HDR? HDR is PQ transfer function, neither 10 bit, not BT.2020 has anything to do with HDR.
https://developer.android.com/training/wide-color-gamut
This talks only about WCG.
This should be used to trigger HDR. https://developer.android.com/ndk/reference/struct/a-hdr-metadata-smpte2086
For Java this should be used to check whether HDR is there.
https://developer.android.com/reference/android/view/Display.HdrCapabilities?hl=en
See this question with further links What is the difference between Display.HdrCapabilities and configuration.isScreenHdr

OpenSceneGraph integration into Qt Quick

I want to integrate OSG scene into my Qt Quick application.
It seems that the proper way to do it is to use QQuickFramebufferObject class and call osgViewer::Viewer::frame() inside QQuickFramebufferObject::Renderer::render(). I've tried to use https://bitbucket.org/leon_manukyan/qtquick2osgitem/overview.
However, it seems this approach doesn't work correctly in all cases. For example, in Android platform this code renders only the first frame.
I think the problem is that QQuickFramebufferObject uses the same OpenGL context both for Qt Quick Scene Graph and code called within QQuickFramebufferObject::Renderer::render().
So I'm wondering, is it possible to integrate OpenSceneGraph into Qt Quick using QQuickFramebufferObject correctly or it is better to use implementation that uses QQuickItem and separate OpenGL context such as https://github.com/podsvirov/osgqtquick?

Is it possible to integrate OpenSceneGraph into Qt Quick using
QQuickFramebufferObject correctly or it is better to use
implementation that uses QQuickItem and separate OpenGL context?
The easiest way would be using QQuickPaintedItem which is derived from QQuickItem. While it is by default offering raster-image type of drawing you can switch its render target to OpenGL FramebufferObject:
QPainter paints into a QOpenGLFramebufferObject using the GL paint
engine. Painting can be faster as no texture upload is required, but
anti-aliasing quality is not as good as if using an image. This render
target allows faster rendering in some cases, but you should avoid
using it if the item is resized often.
MyQQuickItem::MyQQuickItem(QQuickItem* parent) : QQuickPaintedItem(parent)
{
// unless we set the below the render target would be slow rastering
// but we can definitely use the GL paint engine just by doing this:
this->setRenderTarget(QQuickPaintedItem::FramebufferObject);
}
How do we render with this OpenGL target then? The answer can be still good old QPainter filled with the image called on update/paint:
void MyQQuickItem::presentImage(const QImage& img)
{
m_image = img;
update();
}
// must implement
// virtual void QQuickPaintedItem::paint(QPainter *painter) = 0
void MyQQuickItem::paint(QPainter* painter)
{
// or we can precalculate the required output rect
painter->drawImage(this->boundingRect(), m_image);
}
While QOpenGLFramebufferObject used behind the scenes here is not QQuickFramebufferObject the semantics of it is pretty much what the question is about and we've confirmed with the question author that we can use QImage as a source to render in OpenGL.
P.S. I successfully use this technique since Qt 5.7 on PC desktop and singleboard touchscreen Linux device. Just a bit unsure of Android.

Unity canvas scaler hiding animations in high resolution display

I instantiate the following gameObject, which contains an Animator with the mode "always animate" on, the animation goes for 340ms, after that time I destroy the gameObject.
The gameObject Inspector properties:
I instantiate it using the following code:
instancia = (Instantiate(cardAnimation, new Vector3(0, 0, 0), Quaternion.identity) as GameObject).GetComponent<Image>();
instancia.rectTransform.SetParent(transform);
StartCoroutine(KillOnAnimationEnd());
Here is the Coroutine:
private IEnumerator KillOnAnimationEnd()
{
yield return new WaitForSeconds(0.34f);
DestroyImmediate(instancia);
}
Here is how the animation looks like when simulating in Unity (PC-Windows):
But on android after I open the chest it waits 340ms with nothing happening and then show the information above, does this have something to do with the plataform or is some unity or perhaps code related issue?
NOTE: I also have another animation in another scene that is just a already instantiated gameObject in the Hierarchy with always animated on and it works on Android.
--EDIT--
So I have ran the newest version of the app in a emulator which is almost about 1080x480 and the animation showed just as the PC, also running on a 720p smartphone did the job, the only problem I'm still having is with my QuadHD resolution from Galaxy S6, everything else shows but the animation, I have even tried making the animation run without any script so it runs in a loop, but it doesn't show up in galaxy screen.
Given the news about the issue I think this might change a little bit the perspective of answers and perhaps help someone else solve the same problem in the future.

Okay, figured out the problem, its something to do with "rotation" in animations using Unity3D in 2D mode, gonna be reporting it form Unity so it is fixed.
The solution: Animate your UI only using scale/position, if used rotation it will not show on high resolution display.

I am pretty sure your WaitForSeconds(0.34f) is not working properly because there is no thing such as yield keyword in Java. I recommend you to use a invoke method instead to call your method that destroys your GameObject.

Unable to change FOV of the google card board camera

I am developing a sniper game for android using Google card board unity SDK. Now there is the need to tweak the camera's FOV which leads me to interact a variable named 'mockFieldOfView' in CardBoard.cs. Tweaking that value in the Unity editor is fine but as soon as I make a build for Android it doesn't take effect at all. I'm unable to figure out the issue. Any idea or suggestion would be highly appreciated.
Apologize for the late reply, so ouflak you can see complete Cardboard.cs here Cardboard.cs

You don't want to change "mockFieldOfView". That only affects the in-editor FOV. The value you want to change is "matchMonoFOV" on the StereoController. You also have to set a "CenterOfInterest" game object on the StereoController. It makes the stereo FOV attempt to match the FOV on the Main Camera (or whichever camera has the StereoController script).
See StereoController.cs
Update: v0.4.5 of Cardboard SDK supports your use case. Use "matchByZoom" and set the FOV you want on the StereoController's camera. No center of interest is needed.

I had the same issue and in my case it helped to put the MainCamera closer to the object which was the Cockpit of a car in my case.
In order to put the MainCamera closer than 1 real-world-meter to the object you must change the default-minimum-value in Cardboard.cs - I use the following setting:
private readonly Vector2 defaultComfortableViewingRange = new Vector2(0.0f, 100000.0f);

Recenter or Reorient view with Cardboard SDK on Unity

With Unity, the CardboardHead script is added to the main camera and that handles everything quite nicely, but I need to be able to "recenter" the view on demand and the only option I see so far is to rorate the entire scene and it seems like this is something the would address first-hand and I can't find anything in the docs.
With Oculus Mobile SDK (GearVR), it would be OVRCamera.ResetCameraPositionOrientation(Vector3.one, Vector3.zero, Vector3.up, Vector3.zero); though they handle it nicely each time the viewer is put on so it's rarely needed there.

There's a "target" parameter on the CardboardHead that lets you use to another gameobject as a reference for rotation. Or you can use a dummy parent gameobject. Either way, when you want to recenter, you set this reference object's rotation so that the CardboardHead is now pointing forward. Add this function to an script on the CardboardHead (or just add it into that script):
public void Recenter() {
Transform reference = target != null ? target : transform.parent;
if (reference != null) {
reference.rotation = Quaternion.Inverse(transform.rotation) * reference.rotation;
// next line is optional -- try it with and without
reference.rotation = Quaternion.FromToRotation(reference.up, Vector3.up) * reference.rotation;
}
}

Cardboard.SDK.Recenter (); should do the trick.
Recenter orientation Added Recenter() function to Cardboard.SDK, which resets the head tracker so the phone's current heading becomes the forward direction (+Z axis).
Couldn't find the docs for the API/SDK but it's in the release notes for the v0.4.5 Update.

You can rotate the Cardboard Main to point in a certain direction.
This is what worked for me when I wanted the app to start up pointing a certain way. Since the CardboardHead points at Vector3.zero on startup if no target is assigned, I ran a function during Start() for the CardboardMain that would point in the direction I wanted.
Of course, if you're already rotating CardboardMain for some other reason, it may be possible to use this same method by creating a parent of the CardboardHead (child of CardboardMain) and doing the same thing.

This question is a bit old but for Google VR SDK 1.50+ you can do
transform.eulerAngles = new Vector3(newRot.x, newRot.y, newRot.z);
UnityEngine.VR.InputTracking.Recenter();
also, if you don't want to get confused you also need to catch the GvrEditorEmulator instance and Recenter it as well.
#if UNITY_EDITOR
gvrEditorEmulator.Recenter();
#endif
Recentering GvrEditorEmulator though doesn't seem to work very well at the moment but if you disable it you'll see the recentering works for the main camera.