Rendering a Nuclear Explosion with HDR
- Thread starter pat777
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radar1200gs
Regular
I think that a CRT should be able to provide the sort of effect you are after myself.
Just watch the news (political conferences are good) or any television footage that has photographers firing flashguns in the scene.
I find such scenes highly annoying because the screen does a remarkably good job of reproducing the flash, especially if you are sitting side on to the screen, and my TV is only a cheapie.
Just watch the news (political conferences are good) or any television footage that has photographers firing flashguns in the scene.
I find such scenes highly annoying because the screen does a remarkably good job of reproducing the flash, especially if you are sitting side on to the screen, and my TV is only a cheapie.
[shameless plug for a friend]
There will be some HDR displays at SIGGRAPH this year (sporting contrast ratios of well over 50,000:1, vs the typical contrast ratio of today's displays ~300:1):
http://www.cs.ubc.ca/~mmt/Siggraph.04.pdf
There will be some HDR displays at SIGGRAPH this year (sporting contrast ratios of well over 50,000:1, vs the typical contrast ratio of today's displays ~300:1):
http://www.cs.ubc.ca/~mmt/Siggraph.04.pdf
Sorry but i just had to add my contribution to the thread:
overclocked
Veteran
I think someone out there should make a demo of this, ATI,NVIDIA...
50,000:1???????
<-- *Eyes explode*
<-- *Eyes explode*london-boy said:50,000:1???????
Yep. I saw it in action at last year's Siggraph. Quite impressive. Since then I've been trying to convince my manager that if he gives me 2 HDR LCDs and a pair of cheap sunglasses I'll never go outside again! 8)
The system works by having an array of white LEDs as the backlighting. The LEDs have a much greater absolute range that traditional LCD backlights. The LEDs are not 1x1 pixel though -- more like 16x8 (I don't know the exact numbers). Each LED shines as bright as the brightest pixel in it's zone. Then all of the LCD pixels in that zone adjust their filter rates to compensate.
The LEDs have 256 steps of brightness. The LCDs have 256 steps of filter. It's theoretically 65536-to-1 but I think that 50,000-to-1 is more honest (and simpler to market).
In theory if you had a single super bright pixel in the middle of a dark, subtly lit area it would look bad. In practice the glare (real life, in-your-eyes glare) of the bright pixels covers any such problems.
radar1200gs said:
Isn't that actually the lens on the camera causing the light to diffract and go different directions causing glare. Wear glasses and you will notice a lot of lights in RL look just like they do on TV (lens seem to allow for a lot of vertical and horizontal glare but not much along the diagonals, now in the human visual system inside the brain the way your brain pieces together input it uses something a weighting similar to a gaussian distribution for gathering information from several retina cells for each "pixel" you see (its a lot more complex than that but that the kinda glare you see that causes halo's around lights (actually when you see a real halo its caused by another part of the visual system in your brain but that doesn't matter I'm just referring to a light bloom)).
In rthdrbl you can change the various glare types and you will notice they are a bunch of lenses mainly. When its turned off thats just regular light bloom and if you want you can get your CRT to do the same thing by unfocusing the electron guns where it gets brighter (unfortunately if you unfocus the electron gun it gets darker there so you have to increase brightness above normal while defocusing). Heh then you could have a CRT that creates built-in light blooms
Actually I guess you could tell the CRT to add an extra communication wire that says bloom this much.radar1200gs
Regular
Don't really know why the effect is as good as it is, but it can be hugely irritating if you are doing something else and flashes go off on the TV screen. Its just like having the flash go off in the room for real. Very distracting.
On music channels bright strobe lights on screen have a similar effect too.
On music channels bright strobe lights on screen have a similar effect too.
radar1200gs
Regular
No, its just as annoying in broad daylight.
I'm the sort who notices clouds filtering sunlight even indoors especially when trying to read though.
I'm the sort who notices clouds filtering sunlight even indoors especially when trying to read though.
I think more people need to read that pdf...
The actual brightness values of the white LED's in the second prototype was actually 1024 values... That gives the prototype light intensities of 8500mcd with usable contrast ratios in excess of 80,000:1 ?!?!?
HOLY GOD!
Another cool part of the paper was where they talked about using programmable pixel shaders to generate the data needed for the primary light source (the projector or the white-only LED's). They specifically mention the lack of FP framebuffer and FP alpha blending as causing significant performance degredation. I bet if they tried this with an NV40 now, they'd see much better performance.
The actual brightness values of the white LED's in the second prototype was actually 1024 values... That gives the prototype light intensities of 8500mcd with usable contrast ratios in excess of 80,000:1 ?!?!?
HOLY GOD!
Another cool part of the paper was where they talked about using programmable pixel shaders to generate the data needed for the primary light source (the projector or the white-only LED's). They specifically mention the lack of FP framebuffer and FP alpha blending as causing significant performance degredation. I bet if they tried this with an NV40 now, they'd see much better performance.
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