I've tried many 3D augmented reality games animations vs. all of them were based on this concept: your head is on one reference point, standing still, they only allow you to turn your head and look around, maybe arms and legs are included but you are not allowed to walk around or change your position. Right?

Is this because of the graphic processor has enough competing power to look around but not enough power to calculate depth perception when you also move? Because when you calculated, at least 120hz*1080*1080px*3(RGB)*8bits =3359232000 bits data transfer per second is required for monitoring in 1080p resolution with 120 Hz. When you are standing still, 3+ Giga ram may be enough to store calculated datas of other direction of views to cache but when you are moving it may not be enough right? Because your processor will has more like 3 Ghz clk speed and even in most RISC processors calculating new depth perception will require minimum 2-3 assembly instruction step so the processor chip would not be able to support such calculation because even if it achieves to calculate new perception per pixel in 2 steps it will decrease the speed of construction for whole pix lower to 1.5 GHz and the monitor will require minimum 3.3 GHz(I am not counting the dimming information of BLU or RGBs). So, is this the main issue for this or am I wrong and other concerns are included? If so, what are those?


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    \$\begingroup\$ I've seen quite a few VR and AR games that involve movement, so I'm not sure why you'd say there are none. It's not a rendering/processing limitation - game developers have been making fully-explorable 3D spaces for decades, even if the high update rate forces some concessions in terms of fidelity. The figures you've cited are the same for a rendered frame from a stationary or moving perspective, so they're irrelevant to the question you're asking. \$\endgroup\$ – DMGregory Dec 13 '15 at 19:27
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    \$\begingroup\$ Maybe you just haven't looked around enough. Here is one example from Microsoft. youtube.com/watch?v=C3rNIxMlKmI \$\endgroup\$ – Christer Dec 13 '15 at 19:30
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    \$\begingroup\$ To calculate the amount of pixels on 1080p you should say 1920 * 1080 instead of 1080^2 \$\endgroup\$ – KaareZ Dec 13 '15 at 19:40
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    \$\begingroup\$ VR rendering is only more performance-taxing in that you need to render the scene twice - once for each eye. But on the other hand you don't need to render what's already there in the real world, so it can even require less performance. How much performance your rendering takes depends mostly on what level of detail you want. \$\endgroup\$ – Philipp Dec 13 '15 at 20:04
  • \$\begingroup\$ First, there are plenty of 3D games where the character moves. The player doesn't actually walk around to control position, and instead uses the VR headset with a gamepad from a seated position, because otherwise the player would be injured or die and the game developer would lose a customer. Solutions exist: youtube.com/channel/UCqNO2PNJYx9G5yepVEm09bg \$\endgroup\$ – Peter Dec 13 '15 at 22:42

As others have already explained, your question is based on a false premise: that most 3D games don't allow you to move. I think what you actually meant is "Why do you control movement in most VR-first games with a controller, rather than with your body?".

The answer is not to do with technical limitations, but human factors. For most games, it's completely unnecessary - and indeed makes for frustrating gameplay - to control your character with your body rather than a controller. Nobody wants to clear out their room to play a VR FPS only to get annoyed with wires and obstacles. There would be too many compromises needed (unless you literally had a huge hall to play in) to make it so that the controls don't interfere with the game.

That doesn't mean that there aren't games where you can at least move a bit by actually moving your body. The controller is your primary mode of ambulation, but you can still look around corners by moving your head etc. On that front, the commenters on your question are right; most games actually do let you do that.

Regardless, your reasoning is still wrong. Think of a VR headset as just a set of double monitors; anything that can be done on your actual screen can be done here too. IMU input from a headset is equivalent to WASD + mouse or a controller. It has nothing to do with caching a scene in VRAM or limitations of your graphics card or anything of the sort.

The actual UX pitfalls with VR headsets are resolution, FOV, and latency. People might decide to limit how you control your player based on those for example, to prevent motion sickness among other things.

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  • \$\begingroup\$ OK, now I understood my question was full of misleading and wrong statements. However, I still can not do the math. In AR applicatons, there might be 2 seperate graphic processors to drive pixels for each eye. However, in 3D systems with shutter glass, there is only one graphic processor and its clock is not over 4 GHz. You saw the calculation I did, was there something wrong in that? Imagine I constantly change my position while I look around. How will the graphic card manage to support 3D vision? I know graphic cards are not designed for parallel computing. A simple explanation is enough. \$\endgroup\$ – Alper91 Dec 13 '15 at 22:11
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    \$\begingroup\$ I don't see how changing your position is in any way related to how fast your GPU is. Surely that's a constant? And GPUs are designed for exactly that: parallel processing. Just not per-eye but rather per-pixel. Aside from that, anything that can render a scene from one perspective can certainly do it from two at no more than half the frames per second? Even with the same monitor (split screen), you only run a game loop e.g. once for every N times you render a scene per frame. \$\endgroup\$ – Yousef Amar Dec 13 '15 at 22:30
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    \$\begingroup\$ In addition to "frustrating", add "dangerous", "painful" and "darwinistic". Walking in a room while blind and deaf is bad enough, but with VR your eyes and brain are told there isn't a wall directly in front of you and there are no LEGO TM or other torture instruments lying on the floor. And just imagine what happens if a baby crawls into your room while you're playing FIFA 2020 VR edition. \$\endgroup\$ – Peter Dec 13 '15 at 22:32

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