Latency the sine qua non of AR and VRChristmas always makes me think of Mode X which surely requires some explanation, since its not the most common association with this time of year or any time of year, for that matter. IBM introduced the VGA graphics chip in the late 1. Unity Soft Particles Forward Rendering PlantsEGA. The biggest improvement in the VGA was the addition of the first 2. IBM had ever supported Mode 0x. Moreover, Mode 0x. Byzantine architecture of the older 1. So Mode 0x. 13 was a great addition, but it had one downside it was slow. Ingenieria De Software Basada En Componentes Pdf Free more. Mode 0x. 13 only allowed one byte of display memory one pixel to be modified per write access even if you did 1. The hardware used in 1. Main/Inspector-LineRenderer.png' alt='Unity Soft Particles Forward Rendering Programs' title='Unity Soft Particles Forward Rendering Programs' />That four times difference meant that Mode 0x. Mode 0x. 13 also didnt result in square pixels the standard monitor aspect ratio was 4 3, which was a perfect match for the 6. Mode 0x. 13s 3. 202. Mode 0x. 13 was limited to 3. KB, and 3. 202. 40 wouldnt have fit. KB in size. In December of 1. I remember I was rolling Mode 0x. It felt like there was a solution there, but I just couldnt tease it out. One afternoon, my family went to get a Christmas tree, and we brought it back and set it up and started to decorate it. For some reason, the aspect ratio issue started nagging at me, and I remember sitting there for a minute, watching everyone else decorate the tree, phased out while ideas ran through my head, almost like that funny stretch of scrambled thinking just before you fall asleep. KnARYLwNmf0/hqdefault.jpg' alt='Unity Soft Particles Forward Rendering' title='Unity Soft Particles Forward Rendering' />And then, for no apparent reason, it popped into my head Treat it like a 1. You see, the CPU access side of the VGAs frame buffer that is, reading and writing of its contents by software and the CRT controller side reading of pixels to display them turned out to be completely independently configurable. I could leave the CRT controller set up to display 2. CPU access to allow writing to four planes at once, with all the performance benefits of the 1. This meant fills and copies could go four times as fast. Better yet, the 6. KB memory window limitation went away, because now four times as many bytes could be addressed in that window, so a few simple tweaks to get the CRT controller to scan out more lines produced a 3. Unity Soft Particles Forward Rendering BeefI dubbed Mode X and wrote up in the December, 1. Denon Dn-X 1500 Firmware Update here. Dr. Dobbs Journal. Mode X was widely used in games for the next few years, until higher res linear 2. If youre curious about the details of Mode X and theres no reason you should be, because its been a long time since its been useful you can find them here, in Chapters 4. Unity Soft Particles Forward Rendering Services' title='Unity Soft Particles Forward Rendering Services' />One interesting aspect of Mode X is that it was completely obvious in retrospect but then, isnt everything Getting to that breakthrough moment is one of the hardest things there is, because its not a controllable, linear process you need to think and work hard at a problem to make it possible to have the breakthrough, but often you then need to think about or do something anything else, and only then does the key thought slip into your mind while youre not looking for it. The other interesting aspect is that everyone knew that there was a speed of light limit on 2. VGA and then Mode X made it possible to go faster than that limit by changing the hardware rules. You might think of Mode X as a Kobayashi Maru mode. Which brings us, neat as a pin, to todays topic when it comes to latency, virtual reality VR and augmented reality AR are in need of some hardware Kobayashi Maru moments of their own. Latency is fundamental. When it comes to VR and AR, latency is fundamental if you dont have low enough latency, its impossible to deliver good experiences, by which I mean virtual objects that your eyes and brain accept as real. By real, I dont mean that you cant tell theyre virtual by looking at them, but rather that your perception of them as part of the world as you move your eyes, head, and body is indistinguishable from your perception of real objects. The key to this is that virtual objects have to stay in very nearly the same perceived real world locations as you move that is, they have to register as being in almost exactly the right position all the time. Iron Crotch Qigong is a traditional practice followed for thousands of years to protect the male genitalia in China, and has been a major in countless Chinese. We are looking for engineers for our rendering and shading RD team, to help advance rendering technology for photorealistic motion picture visual effects production. Being right 9. 9 percent of the time is no good, because the occasional mis registration is precisely the sort of thing your visual system is designed to detect, and will stick out like a sore thumb. Assuming accurate, consistent tracking and thats a big if, as Ill explain one of these days, the enemy of virtual registration is latency. If too much time elapses between the time your head starts to turn and the time the image is redrawn to account for the new pose, the virtual image will drift far enough so that it has clearly wobbled in VR, or so that is obviously no longer aligned with the same real world features in AR. How much latency is too much Less than you might think. For reference, games generally have latency from mouse movement to screen update of 5. Ive seen numbers as low as about 3. Unity Soft Particles Forward Rendering Companies' title='Unity Soft Particles Forward Rendering Companies' />In contrast, I can tell you from personal experience that more than 2. Open Psd File Gimp Cmyk. VR and especially AR, but research indicates that 1. ARVR is so much more latency sensitive than normal games because, as described above, theyre expected to stay stable with respect to the real world as you move, while with normal games, your eye and brain know theyre looking at a picture. With ARVR, all the processing power that originally served to detect anomalies that might indicate the approach of a predator or the availability of prey is brought to bear on bringing virtual images that are wrong by more than a tiny bit to your attention. That includes images that shift when you move, rather than staying where theyre supposed to be and thats exactly the effect that latency has. Suppose you rotate your head at 6. That sounds fast, but in fact its just a slow turn you are capable of moving your head at hundreds of degreessecond. Also suppose that latency is 5. K x 1. K over a 1. FOV. Then as your head turns, the virtual images being displayed are based on 5. Put another way, the object positions are wrong by 3. Either way, the error is very noticeable. You can do prediction to move the drawing position to the right place, and that works pretty well most of the time. Unfortunately, when there is a sudden change of direction, the error becomes even bigger than with no prediction. Again, its the anomalies that are noticeable, and reversal of direction is a common situation that causes huge anomalies. Finally, latency seems to be connected to simulator sickness, and the higher the latency, the worse the effect. So we need to get latency down to 2. Even 2. 0 ms is very hard to achieve on existing hardware, and 7 ms, while not impossible, would require significant compromises and some true Kobayashi Maru maneuvers. Lets look at why that is. The following steps have to happen in order to draw a properly registered ARVR image 1 Tracking has to determine the exact pose of the HMD that is, the exact position and orientation in the real world. The application has to render the scene, in stereo, as viewed from that pose. Antialiasing is not required but is a big plus, because, as explained in the last post, pixel density is low for wide FOV HMDs. The graphics hardware has to transfer the rendered scene to the HMDs display. This is called scan out, and involves reading sequentially through the frame buffer from top to bottom, moving right to left within each scan line, and streaming the pixel data for the scene over a link such as HDMI to the display.