為了能讓游戲玩家感受身歷其境的臨場體驗(yàn)，頭戴式虛擬實(shí)境(VR)眼鏡的開發(fā)進(jìn)展如今已能實(shí)現(xiàn)逼近15毫秒的反應(yīng)時(shí)間了。開發(fā)人員們展現(xiàn)高超絕技實(shí)現(xiàn)了超低延遲，從而催生出新一類的計(jì)算機(jī)游戲。
在日前于AMD年度開發(fā)者大會(huì)上，Oculus VR公司首席執(zhí)行官Brendan Iribe強(qiáng)調(diào)，“我們將重新點(diǎn)燃起已在2D屏幕上趨于穩(wěn)定的 CPU / GPU競賽。”
Oculus VR公司展示的 Oculus Rift 頭戴式虛擬眼鏡原型在執(zhí)行時(shí)的延遲已低于20ms，并即將邁向7-15ms的神圣目標(biāo)?！拔覀兡壳吧形催_(dá)到目標(biāo)，但我們很快就能實(shí)現(xiàn)了，”但I(xiàn)ribe并 未透露該公司何時(shí)推出眾所期待的 Oculus Rift 頭戴式耳機(jī)。
這一問題就在于用戶移動(dòng)頭部的速度通常比頭戴式眼鏡顯示一幅新影像的速度更快。為了盡量趕上與用戶頭部移動(dòng)同樣的速度，可能造成顯示器上的影像變得模糊，甚至讓用戶感到暈眩惡心。
用戶的頭部動(dòng)作以及像素傳送至顯示器二者之間的平均延遲約有45秒。當(dāng)今的游戲引擎需要其中約三分之一的時(shí)間定義與呈現(xiàn)一格新畫面，同時(shí)，顯示器也需要另外三分之一的時(shí)間來激活像素。
因此，Iribe指出，Oculus公司正針對(duì)顯示器上的影像連貫性進(jìn)行各種研發(fā)。此外，目前的1,920×1,080原型使用OLED屏幕，可支持1ms 的切換時(shí)間。Oculus公司使用所謂的時(shí)間扭曲(time warping)機(jī)制，能以每秒80-95格的最大顯示速率呈現(xiàn)畫面，明顯比游戲引擎快得多了。他解釋說，“它其實(shí)是用一種欺騙人眼的方式，但帶來了極致 的體驗(yàn)?！?
Oculus公司最近還延攬了John Carmack為公司首席技術(shù)官。John Carmack曾經(jīng)參與《毀滅戰(zhàn)士》(Doom)與《雷神之錘》(Quake)等PC游戲的開發(fā)?！稓鐟?zhàn)士》與《雷神之錘》加速了PC用3D加速器的興起。
John Carmack正沉浸于Oculus Rift游戲體驗(yàn)中
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頭戴式虛擬實(shí)境眼鏡可望實(shí)現(xiàn)新一類身臨其境的游戲以及充滿想象力的應(yīng)用程序。
“游戲原型內(nèi)部帶來的最好的體驗(yàn)之一是讓用戶真的漂浮在整個(gè)空間世界，以及讓人贊嘆于其浩瀚規(guī)模，”他說，“目前已開發(fā)出數(shù)百種VR游戲了，許多都來自獨(dú)立制作，因?yàn)樗且环N全新的平臺(tái)──VR將改變世界，”他說。
目前看來，想擺脫頭戴式眼鏡而仍保持與用戶動(dòng)作同步的終極目標(biāo)，還有很長遠(yuǎn)的路要走?！澳憧赡軙?huì)想在虛擬世界中看到你的手，以及透過眼睛追蹤，但這在第一版游戲中還未能實(shí)現(xiàn)?！钡獻(xiàn)ribe強(qiáng)調(diào)，這些都已經(jīng)是該公司下一階段的開發(fā)方向了。
此外，在展示現(xiàn)場，一位來賓詢問這種頭戴式眼鏡是否也適用于戴眼鏡的玩家？ Iribe幽默地說：“當(dāng)然，這已經(jīng)列為我們開發(fā)工作的最優(yōu)先項(xiàng)目了，因?yàn)槲易约阂泊餮坨R！”
本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載
編譯：Susan Hong
參考英文原文：VR Goggles Play Games With Latency，by Rick Merritt
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VR Goggles Play Games With Latency
Rick Merritt
SAN JOSE, Calif. – Virtual reality goggles are edging close to a 15 millisecond response time in an effort to deliver immersive experiences that put game players into a scene. Developers have a few tricks up their sleeves to get to the ultra-low latency that could give birth to a new class of computer games.
"We will reignite the CPU/GPU race which plateaued on 2D screens," said Brendan Iribe, chief executive of Oculus VR in a keynote at AMD's annual developer conference here.
Prototype headsets are already running with latency of less than 20ms, edging toward the Holy Grail of 7-15ms. "We are not there today, but we are getting there very quickly," said Iribe who declined to give a ship date for the company's much anticipated Oculus Rift headset.
The problem is that users can move their heads faster than the headsets can render a new image. Displays can smear images as they try to catch up, giving users nausea.
The average latency between a user's head motion and a new pixel delivered to a display is about 45 milliseconds. Today's game engines need about a third of that time to define and render a new frame and displays need another third to switch on the pixels.
Oculus is "doing all kinds of R&D" on image persistence on a display, said Iribe. "Most of the [60 frames/second] view is black with displays mostly turned off except for the 1-2ms when they are exactly aligned" with the user's head, he said.
In addition, the current 1920 x 1080 prototypes use OLED screens that sport a 1ms switching time. Also, Oculus uses what it calls time warping, rending scenes at the maximum display rate of 80 to 95 frames/second, significantly faster than the game engine. "It's tricking your eyes, and it's a great experience," he said.
Oculus recently recruited as its chief technologist John Carmack, developer of PC games such as Doom and Quake that fueled the rise of 3D accelerator chips for PCs.
John Carmack is immersed in work on Oculus Rift.
Virtual reality goggles promise new immersive games and fantasy apps.
"One of best experiences in prototype internally is literally floating through a space world and being amazed at the scale," he said "There are hundreds of VR games being made, many by indies because it’s a new platform -- VR will change the world," he said.
There's a long horizon beyond the ambitious goal of getting out a headset that can keep up with a moving user. "You want to see your hands [in the virtual world] and you want eye tracking, but it's not going to happen for version one," he said.
An audience member asked for headsets that can work for people who wear glasses. "It's at the top of the priority list -- I wear glasses, too," he said.
