Passthrough Quality, Performance, and Aligment¶
Two topic in this chapter. Quality and Aligment.
Quality and Performance¶
The Passthrough enables the environment camera on HMD and this costs performance. VIVE Wave™ provides quality and performance control APIs for all passthrough feature, overlay, underlay and projected passthrough. These APIs can help developers to make the balance between the quality and performance.
APIs¶
Set Passthrough Image Quality¶
Default Mode
After your app is launched, this is the default setting. The passthrough image will not be very sharp. And the performance is not heavy.
Performance Mode
Setting to this mode, the passthrough image will be softer, and the system cost will be lower.
Quality Mode
Setting to this mode, the passthrough image will be sharper, and the system cost will be higher.
If return false, the feature might not available in this device.
Set Passthrough Image Rate¶
For the Rate options:
Boost
Default passthrough image’s refresh rate.
Normal
Reduce the passthrough image’s refresh rate for performance improvement.
Set Frame Rate¶
In practice, a lower traget frame rate can help the final FPS be more stable when you show passthrough underlay, and can help the actions in the VR/MR be more smooth.
This API can let you set the target frame rate.
You should set the Frame Rate by one of available frame rates. See Get Available Frame Rates
Get Frame Rate¶
This API can let you get the current target frame rate.
Get Available Frame Rates¶
This API can let you get the possible target frame rates supported by the system. Use the value in the return array to set the frame rate.
You can use following blueprint to set higher or lower target frame rate.
Alignment¶
The passthorugh image is taken by single environment camera. In the passthrough, the real objects which is closed to the camera will not have a correct depth. If visual object rendered in the a correct depth, a missalignment will be happen between visual object and passthrough image.
VIVE Wave™ can align your visual controller with the real controller in the passthrough image. This can help immersive better if no multiple hand or controller is shown in your vision.
However, with this effect you will see the passthrough image distorted around your controller. The visual content around your hand will be not distorted but the background image be distored. You can choose another mode if you need the background be smooth.
In practice, if player see more visual object in your design, it is better to set to the View mode. if player focus the visual object holded on hand, it is better to set to the Scale mode. You can switch it when necessary.
