https://www.reddit.com/r/oculus/comments/8fbp7q/my_personal_comparison_of_the_current_pc_vr/
https://tinyurl.com/ycs6heh5 pcvr
https://www.reddit.com/r/oculus/comments/8ggupw/comparison_of_standalone_vr_systems_updated/
https://tinyurl.com/y8tg75ke standalone
有趣的是 Pixel density他用的是PPD
Pixels per Degree (PPD)
经过透镜投影到眼睛的pixel
3K屏 在40度的时候 比2k 高1.3倍
40度应该是正前方??