Determining a predicted head pose time
Techniques for calculating a predicted head pose time for a display device are described herein. A request to start a frame is generated. A target finish time stamp associated with rendering the frame is calculated. A number of VSync periods from a last VSync to a target VSync is determined based on the target finish time stamp. A target VSync time stamp is calculated based on the number of VSync periods from the last VSync to the target VSync. The target VSync time stamp is compared to the target finish time stamp. The predicted head pose time is calculated based on the target VSync time stamp and a fixed platform offset.
1. A method of operating a display device, the method comprising:
generating a request to start a frame, wherein the frame is to be displayed by the display device;
calculating a target finish time stamp associated with rendering the frame, wherein the target finish time stamp is calculated based on a first amount of time for one or more processors to generate the frame;
determining a number of VSync periods from a last VSync to a target VSync based on the target finish time stamp to obtain a target VSync time stamp; and
calculating a predicted head pose time based on the target VSync time stamp and a fixed platform offset, wherein the fixed platform offset relates to a second amount of time for transferring the frame to the display device for display.
2. The method of claim 1 , further comprising:
comparing the target VSync time stamp to the target finish time stamp; and
based on the comparison, delaying the target VSync time stamp by 1 VSync period.
3. The method of claim 1 , further comprising:
providing the predicted head pose time to a head pose estimator.
4. The method of claim 1 , further comprising:
calculating a head pose based on the predicted head pose time.
5. The method of claim 1 , further comprising:
rendering the frame based on the predicted head pose time.
6. The method of claim 1 , further comprising:
displaying virtual content at the display device based on the predicted head pose time.
7. The method of claim 1 , wherein the display device is an augmented reality (AR) device.
8. A system comprising:
a processor; and
a computer-readable medium comprising instructions that, when executed by the processor, cause the processor to perform operations comprising:
generating a request to start a frame, wherein the frame is to be displayed by a display device;
calculating a target finish time stamp associated with rendering the frame, wherein the target finish time stamp is calculated based on a first amount of time for one or more processors to generate the frame;
determining a number of VSync periods from a last VSync to a target VSync based on the target finish time stamp to obtain a target VSync time stamp; and
calculating a predicted head pose time based on the target VSync time stamp and a fixed platform offset, wherein the fixed platform offset relates to a second amount of time for transferring the frame to the display device for display.
9. The system of claim 8 , wherein the operations further comprise:
comparing the target VSync time stamp to the target finish time stamp; and
based on the comparison, delaying the target VSync time stamp by 1 VSync period.
10. The system of claim 8 , wherein the operations further comprise:
providing the predicted head pose time to a head pose estimator.
11. The system of claim 8 , wherein the operations further comprise:
calculating a head pose based on the predicted head pose time.
12. The system of claim 8 , wherein the operations further comprise:
rendering the frame based on the predicted head pose time.
13. The system of claim 8 , wherein the operations further comprise:
displaying virtual content at the display device based on the predicted head pose time.
14. The system of claim 8 , wherein the display device is an augmented reality (AR) device.
15. A non-transitory computer-readable medium comprising instructions that, when executed by a processor, cause the processor to perform operations comprising:
generating a request to start a frame, wherein the frame is to be displayed by a display device;
calculating a target finish time stamp associated with rendering the frame, wherein the target finish time stamp is calculated based on a first amount of time for one or more processors to generate the frame;
determining a number of VSync periods from a last VSync to a target VSync based on the target finish time stamp to obtain a target VSync time stamp; and
calculating a predicted head pose time based on the target VSync time stamp and a fixed platform offset, wherein the fixed platform offset relates to a second amount of time for transferring the frame to the display device for display.
16. The non-transitory computer-readable medium of claim 15 , wherein the operations further comprise:
comparing the target VSync time stamp to the target finish time stamp; and
based on the comparison, delaying the target VSync time stamp by 1 VSync period.
17. The non-transitory computer-readable medium of claim 15 , wherein the operations further comprise:
providing the predicted head pose time to a head pose estimator.
18. The non-transitory computer-readable medium of claim 15 , wherein the operations further comprise:
calculating a head pose based on the predicted head pose time.
19. The non-transitory computer-readable medium of claim 15 , wherein the operations further comprise:
rendering the frame based on the predicted head pose time.
20. The non-transitory computer-readable medium of claim 15 , wherein the operations further comprise:
displaying virtual content at the display device based on the predicted head pose time.