what is HDR?

[lans]

Just wondering what is meant by HDR, I asked this earlier in a thread - but the reply was just "high dynamic range".Now I know that it was obviously an abbreviation, but what exactly does it mean? what effects does it showcase?

 

[FISKER_Q]

basicly just a technology that's gives that blurred bright light at the edges when seeing a object in the sun.

Someone can probably come with a more technology correct version, but whatever

 

[PvtRyan]

Lets just say its light that is not limited by 8-bit values (0-255) of brightness.
In other games, a lightbulb will have the color white, which is 255,255,255 but the sun has that color too, eventhough it's MUCH brighter. With HDR the values of the sun can be someting like 1000,1000,1000
Your monitor can't display anything brighter than white (it can't display 1000,1000,1000), but you can fake it.
If the brightness is over a certain value, post-processing effects are applied, like light blooms and glare effects. Which you see in the HDR video.

 

[tEd]

With HDR you can capture more realisticly very bright or very dark areas of a scene.

 

[x84D80Yx]

basically

its like 2 things.
1 example- when your focused on a object in real life, say a soda can, the background behind it is blurred, or when you focus on the background, the soda can is kinda blurred.

2nd example- when you look at a object that has a very bright lightsource behind it it the object you look at is darkened and can make it look smaller due to the light.

no games really use HDR yet. HDR just makes a game all the more realistic

 

[CrazyHarij]

Fenric explained it a while ago, here have a spade and start digging

 

[Play4Fun]

basically

its like 2 things.
1 example- when your focused on a object in real life, say a soda can, the background behind it is blurred, or when you focus on the background, the soda can is kinda blurred.

2nd example- when you look at a object that has a very bright lightsource behind it it the object you look at is darkened and can make it look smaller due to the light.

no games really use HDR yet. HDR just makes a game all the more realistic

wow! cool...didnt know

 

[Shuzer]

basically

its like 2 things.
1 example- when your focused on a object in real life, say a soda can, the background behind it is blurred, or when you focus on the background, the soda can is kinda blurred.

2nd example- when you look at a object that has a very bright lightsource behind it it the object you look at is darkened and can make it look smaller due to the light.

no games really use HDR yet. HDR just makes a game all the more realistic

That's not HDR :|

Refer to PvtRyan's post for a proper explanation

 

[M1RAG3]

First off, what was described earlier is called "Depth of Field" meaning the transition\blur brought about by the aperture and lens shape of a camera. (Which really has nothing to do with HDRI, to some extent i.e. extreme bright light sources can cause whitewash and a blurring effect to surrounding objects, kind of like the “glow” effect).

Secondly, HDR also known as HDRI (High Dynamic Range Imaging) is a way to fake the actual luminosity levels in real life (not the 8-bit limitation mentioned earlier being 255,255,255 <--- RGB Values) with an HDR Image the level is actually in the 10,000 range (not just in the thousands) which can be seen directly in the HL2 dx9 demo, with the "glow" effect from the sun brought about by the simulation of extreme levels of luminosity.

For further information on the details of the HDRI specs and the process of making one, check out Paul Devebec's website, http://www.debevec.org.

 

[trantjd]

basically

its like 2 things.
1 example- when your focused on a object in real life, say a soda can, the background behind it is blurred, or when you focus on the background, the soda can is kinda blurred.

2nd example- when you look at a object that has a very bright lightsource behind it it the object you look at is darkened and can make it look smaller due to the light.

no games really use HDR yet. HDR just makes a game all the more realistic

That first example is actually depth of field and has nothing to do with lighting (HDR). Depth of field hasn't been implemented in any games that I know of...it's just too hard to decide what to have in focus and what to have out of focus in a game. I've seen it in cutscenes, but not in actual gameplay. It could be a cool tool to draw somebody's attention to a certain item though. But dynamically focusing on whatever is at the center of the screen and blurring everything else according to the distance from the viewer would be distracting and make it more difficult to play.

Your second example is more correct, but look to the other descriptions for a better idea of the tech.

 

[PvtRyan]

He's not completely wrong though, because according to Epic DOF does need HDR (High Dynamic Range, it's not only for lighting). I don't know why though.

64-bit color High Dynamic Range rendering pipeline. The gamma-correct, linear color space renderer provides for immaculate color precision while supporting a wide range of post processing effects such as light blooms, lenticular halos, and depth-of-field.

Source: www.unrealtechnology.com

 

[trantjd]

He's not completely wrong though, because according to Epic DOF does need HDR (High Dynamic Range, it's not only for lighting). I don't know why though.


Source: www.unrealtechnology.com

Interesting...ya learn something new everyday. I'd be interested in reading how HDR is used to creat DoF...

 

[Brian Damage]

My Atomic Computing mag says that HDR also helps to prevent textures becoming muddy in dark areas, or washed-out in bright ones.

 

[obsidian]

HDR is only need in DOF becuase of its greater precision.

 

[Whatup1049]

I hope it's included in HL2 cause I got the rig to handle all that.

 

[Vany.K]

http://en.wikipedia.org/wiki/High_Dynamic_Range