Advanced lighting?

The place to discuss creating, porting and modifying Celestia's source code.
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t00fri
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Post #41by t00fri » 24.10.2007, 23:38

dirkpitt wrote:
chris wrote:light forward scattered by the atmosphere will make Venus appear brilliant even at 180, though Celestia doesn't account for this in it's magnitude calculation.

In fact a quick search also uncovered a page of Venus transit observations that describe this Titan-like atmospheric "ring": Transit of Venus 2004


No problem to model with our Mie parameters, of course. (backscattering)

Bye Fridger
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dirkpitt
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Post #42by dirkpitt » 28.10.2007, 08:11

Weekend update: Fixed a lot of obvious bugs last week. Now stars dim out if a bright sun is in the scene!

Mercury in shadow - even though we're looking at the dim, night side of Mercury almost no stars are visible
since the bright sun is in the scene:
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Mercury totally eclipsing the sun - stars are visible:
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I also implemented temporal adaptation of exposure. This is impossible to demonstrate without a video, but put simply
it means if you go to a brightly lit scene the brightness does not change suddenly, but smoothly (exponentially) with time.
This simulates the way the human eye reacts to changes in brightness.

Last couple of shots are just showing off bloom working on models.
Hubble glinting in the sun:
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Bloom turned off ("|" key):
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dirkpitt
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Post #43by dirkpitt » 28.10.2007, 08:17

Other bugs fixed:
- Bloom effect is now correctly skipped for point stars, orbits/labels/markers
(achieved by writing black (1-a) alpha for lines, but this unfortunately breaks line smoothing,
but luckily FSAA still works for smoothing lines)

Outstanding issues:
- Stars are not visible from the ground! A smarter magnitude calculation that better takes into account viewing direction is needed.
- Moon does not shine when viewed from the ground at night. Not sure why.. :(
- Night lights are too bright

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Chuft-Captain
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Post #44by Chuft-Captain » 28.10.2007, 08:56

Good stuff Dirkpitt!

Who said Celestia development was dead? :wink:

A question:
Is it correct to assume that all these improvements only apply to the OGL2 path???
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

srosenow_98
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Post #45by srosenow_98 » 28.10.2007, 09:18

8O 8O 8O

I'm just speechless at this!

symaski62
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Post #46by symaski62 » 28.10.2007, 13:49

celestia 1.5.0 pre 3

nvidia 169.01 version BETA

Fournisseur : NVIDIA Corporation
Moteur de rendu : GeForce 6200/AGP/SSE/3DNOW!
Version : 2.1.2
Version GLSG : 1.20 NVIDIA via Cg compiler
Nombre max de textures : 4
Taille de texture max. : 4096
Plage de taille de point : 1.000000 - 63.375000


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----------------------------------------
Ctrl+V

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windows 10 directX 12 version
celestia 1.7.0 64 bits
with a general handicap of 80% and it makes much d' efforts for the community and s' expimer, thank you d' to be understanding.

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dirkpitt
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Post #47by dirkpitt » 28.10.2007, 14:09

Chuft-Captain wrote:Is it correct to assume that all these improvements only apply to the OGL2 path???


Incorrect - My HDR code works on all render paths, not just OGL2.
Also any card that can do alpha blending will work - basically any video card.

symaski62 - not sure what you're saying, but the HDR functionality I have shown in this forum thread is not yet available in any release of Celestia.
The screenshots are from my private, experimental build.

symaski62
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Post #48by symaski62 » 28.10.2007, 14:37

dirkpitt wrote:symaski62 - not sure what you're saying, but the HDR functionality I have shown in this forum thread is not yet available in any release of Celestia.
The screenshots are from my private, experimental build.


TESTE video Hubble

http://www.dailymotion.com/symaski62/vi ... videogames

:evil:
windows 10 directX 12 version
celestia 1.7.0 64 bits
with a general handicap of 80% and it makes much d' efforts for the community and s' expimer, thank you d' to be understanding.

ElChristou
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Post #49by ElChristou » 28.10.2007, 19:21

dirkpitt wrote:Other bugs fixed:
- Bloom effect is now correctly skipped for point stars, orbits/labels/markers
(achieved by writing black (1-a) alpha for lines, but this unfortunately breaks line smoothing,
but luckily FSAA still works for smoothing lines)

Outstanding issues:
- Stars are not visible from the ground! A smarter magnitude calculation that better takes into account viewing direction is needed.
- Moon does not shine when viewed from the ground at night. Not sure why.. :(
- Night lights are too bright


Still not time for a buggy test App?? :mrgreen:
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dirkpitt
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Post #50by dirkpitt » 28.10.2007, 23:14

Christophe, not yet! I want to correct this issue first:

- Stars are not visible from the ground! A smarter magnitude calculation that better takes into account viewing direction is needed.

EDIT: Fixed this bug.

I'm still puzzled by the "dark Moon" issue..
Is it just me, or is the moon in the current version of Celestia (no HDR) too dark? Just look at this:

Image

This screenshot was taken about 600m from the Earth's surface. Lunar lambert is being used. The brightest pixel is only about 0.45 (out of max 1.0).
But I could swear that the full moon as viewed by the naked eye looks white and glows.
What's going on here?
Last edited by dirkpitt on 29.10.2007, 03:44, edited 1 time in total.

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selden
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Post #51by selden » 29.10.2007, 00:30

Yes, the default brightness of the Moon is too dim in pre4. :(

p.s. The Moon seems to have slightly brighter hightlights in v1.4.0 and v1.4.1. I think the lambert function may be part of the "problem" but that the over-all brightness does need to be increased.
Selden

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dirkpitt
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Post #52by dirkpitt » 29.10.2007, 04:29

Wow, don't know what took me so long to discover this paper:

A Physically-Based Nightsky Model (SIGGRAPH 2001)

Apparently the "glow" has less to do with glare due to the brightness of the moon, and more to do with atmospheric scattering.

It's my guess that, we see the halo and interpret it as looking "bright", i.e., it's a purely perceptual effect.
So the solution to the dark-moon issue would be to implement scattering for any light sources viewed through
Celestia's atmospheres.
The trick would be to calculate the amount of scattering correctly, then apply my bloom filter.

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Post #53by ElChristou » 29.10.2007, 09:53

dirkpitt wrote:Christophe, not yet! I want to correct this issue first:

- Stars are not visible from the ground! A smarter magnitude calculation that better takes into account viewing direction is needed.

EDIT: Fixed this bug.

So... ...Buggy test App?? :mrgreen: (again! :wink:)
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dirkpitt
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Post #54by dirkpitt » 30.10.2007, 22:45

Stars from the ground are still not fixed. :(
I just discovered a new issue where the stars become too bright at night, resulting in giant blobs of light (star glares) covering the sky. Yuck!

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dirkpitt
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Post #55by dirkpitt » 31.10.2007, 23:15

Finally fixed the star bug, I think.

Cham, ElChristou: I sent you mail.

ElChristou
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Post #56by ElChristou » 01.11.2007, 00:28

dirkpitt wrote:Finally fixed the star bug, I think.

Cham, ElChristou: I sent you mail.


Rahhh.... no words...

This stuff is just brilliant, horribly slow on my poor config but just brilliant...
I LOVE the way stars fade in/out depending on the approach of a planet... SO much realistic...
I LOVE when you enter the shadow cone and suddenly all is just stars...

Really guys, THAT's the direction Celestia MUST take!

Ok, this will perhaps no please everybody, HDR should be (perhaps during a time) an option, but definitively it's a must...

TX A LOT DW to dig this stuff, I hope the dev team will follow to help polishing...

BRAVO!
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ElChristou
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Post #57by ElChristou » 01.11.2007, 16:20

And the CSM is all shiny! This stuff give the impression of one of those old shots a bit blurry! Really nice! :D

(click to enlarge)

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BobHegwood
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Post #58by BobHegwood » 01.11.2007, 22:52

Very, VERY nice...
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Gateway Pentium Dual-Core CPU E5200, 2.5GHz
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Vincent
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Post #59by Vincent » 02.11.2007, 10:34

Da Woon,

That looks superb and promising !

Please, could you make your patch available to a Windows user too ? :roll:
I'm really looking forward to testing it !
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Hungry4info
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Post #60by Hungry4info » 02.11.2007, 13:13

Wow, very nice screenshots! I look foreward to this experiments completion :D
Current Setup:
Windows 7 64 bit. Celestia 1.6.0.
AMD Athlon Processor, 1.6 Ghz, 3 Gb RAM
ATI Radeon HD 3200 Graphics


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