Planetside Software Forums

General => Image Sharing => Topic started by: Dune on August 28, 2012, 12:16:19 PM

Title: Full moon
Post by: Dune on August 28, 2012, 12:16:19 PM
Yossam's Night Time sparked off my  endeavour for a moonscape. I restricted the minimum height of the stars by a distribution shader, using huge numbers for height and fuzzy zone (2000000 or so) and Y as offset.  The moon's image map is put through the luminosity input of a default shader to make it glow. The definition of the map is a bit lost by compression, however.
Title: Re: Full moon
Post by: inkydigit on August 28, 2012, 12:58:12 PM
great settings Ulco, and a nice little scene here too!
:)
Title: Re: Full moon
Post by: masonspappy on August 28, 2012, 01:40:30 PM
It's a great image - very well done.  I do think the moon's gray areas need to be a bit darker
- Cam
Title: Re: Full moon
Post by: Dune on August 29, 2012, 02:59:51 AM
I was experimenting with PNG, but only had 128 colors, so here's a jpg at 95% quality. The terrain itself was just flung together, I'm afraid. I might do another one, with nicer clouds as well.
Title: Re: Full moon
Post by: choronr on August 29, 2012, 01:53:44 PM
Very nice Ulco. Maybe the moon lust a bit lower; and, a bit larger with a tad of yellowish tint.
Title: Re: Full moon
Post by: Dune on August 30, 2012, 01:22:00 AM
For reality sake I should decrease the moon's size I suppose, but a large yellowish moon would be nice, indeed.

I combined my grass experiment with the moon. But after all, I think real grasses give a better result.
Title: Re: Full moon
Post by: TheBadger on August 30, 2012, 05:44:12 AM
Like the last image. Could easily be a shot from a fantasy flick.
Title: Re: Full moon
Post by: jamfull on August 31, 2012, 05:59:56 AM
Nice!

James
Title: Re: Full moon
Post by: masonspappy on August 31, 2012, 01:00:56 PM
 :) Like this!  :)
Title: Re: Full moon
Post by: bigben on August 31, 2012, 10:23:30 PM
Nothing like a full moon to bring out the nerd in me  ;) 

Here's a twist on a moon model.

Second planet with a texture map (http://www.celestiamotherlode.net/creators/hermes/moon-4k.zip (http://www.celestiamotherlode.net/creators/hermes/moon-4k.zip)) and second sun for moonlight. Position of both matched by using the heading/elevation settings. Colour adjust shader lightens the texture image. Background is only included because I had to change the size to put it behind the moon. Texture positioned by matching rotation of the planet to its heading and elevation.

Phase of the  moon is then set by the position of the sun (as it should), other tweaks are done in your atmosphere settings.  Having visible atmospheric glow around a partial phase of the moon is still a bit problematic, but then you guys are all wimping out with a full moon  :P

If it looks upside down it's probably just because the water goes anti-clockwise down the toilet when you flush.

[edit] had the rotation angles on the wrong axis.. swapped XY to correct.[/edit]
Title: Re: Full moon
Post by: Dune on September 01, 2012, 03:50:53 AM
Thanks for your input, Ben. Martin (Dandel0) had a nice way to restrict the glow to the lit side in his moon post. http://www.planetside.co.uk/forums/index.php?topic=15027.0 (http://www.planetside.co.uk/forums/index.php?topic=15027.0) So I guess we're all set now.
Title: Re: Full moon
Post by: TheBadger on September 01, 2012, 05:00:42 AM
Thanks Ben. Thanks for that link Ulco.

Oops, I mean reminding. Have to get that data down too!
Title: Re: Full moon
Post by: bigben on September 01, 2012, 05:04:12 AM
Not entirely... That looks like it's using an atmosphere on the moon. Looks great for that type of scene, but it may fail for a gibbous moon as the sunlight wouldn't be coming from behind to create the glow.  I have an idea for a simple hack but it's not very flexible.

By coincidence I went looking for some better elevation data of the moon and finished up at the same site Dandelo mentions.  Going for the 256px/deg... 4 tiles down, 6 to go ;)
Title: Re: Full moon
Post by: bigben on September 01, 2012, 06:52:52 AM
Hmmm... it worked   :o  Possibly not the most practical but it was an interesting concept to try out.

A couple of things to note.  Whilst I modeled the moon with relatively realistic numbers the default sunlight diameter of 0.5° was just a little wide (the moon should have been a tad wider than 0.5°). Dropped it back to 0.49°. While visible disc was not checked, the diameter still has an effect on where the glow starts. Setting it to something really small gives you a bright point of light so the best compromise IMO is to match it to the diameter of the moon.

The problem in my images above is that the shaded part of the moon reduces the density of the glow effect. Solution: Only render the portion of the moon lit by the sun.
1. Create square image with a white circle.
2. Load into PTGui and set as a 185° circular fisheye image (a few extra degrees to catch mountains/craters on the terminator when I add the bump map)
3. Set its yaw and pitch to match the heading and elevation of the sun
4. Create 360x180° equirectangular image

Add this image to internal network of moon, spherical projection, same position as moon. Connect to opacity function of default shader.

Fixes one problem but it would also allow stars behind the dark side of the moon to show through, although with a bit of luck the atmospheric glow will be high enough to disguise it. It also means you have to create a new mask image whenever the sun changes position (although there are ways to do this on the fly for animations)

For phases smaller than a half moon it may be necessary to switch to a rectangular source image (equirectangular projection) for PTGui to create a mask to render just a wedge of the moon, but there may be other factors for why this may not be a good idea in that situation.
Title: Re: Full moon
Post by: bigben on September 01, 2012, 09:11:49 AM
And finally a larger render with bump map.
http://www.flickr.com/photos/ben-kreunen/7906046786/sizes/o/ (http://www.flickr.com/photos/ben-kreunen/7906046786/sizes/o/)
4K texture, 7K elevation image (8bit TIFF), slightly exaggerated displacement (20km)
Detail: 1, atmosphere turned off.  Sweet :)
Half size below
Title: Re: Full moon
Post by: bigben on September 01, 2012, 09:08:48 PM
Changed the background colour to check I had this correct, and it wasn't exactly in the example above but it does work in principle. 

Figuring out the transformation of the mask image is doing my head in. Creating a full moon facing the viewer is easy...  the yaw and pitch of the image is just the opposite of the heading and altitude of the planet (the texture is rotated with the planet). The result then has to be transformed to face the hemisphere at the sun.  Time for a paper and pencil  ;)

Quote from: bigben on September 01, 2012, 06:52:52 AM
... For phases smaller than a half moon it may be necessary to switch to a rectangular source image (equirectangular projection) for PTGui to create a mask to render just a wedge of the moon, but there may be other factors for why this may not be a good idea in that situation.


This is wrong (in a good way). I forgot that the planet only renders a single side, so the inside of the hemisphere isn't rendered for a crescent moon :)
Title: Re: Full moon
Post by: Dune on September 03, 2012, 12:43:09 PM
As mentioned in Luno (Dandel0's post): Some experimenting with glow and moon and used a very high 'cirrus' cloud behind the moon, plus a rather large (4) sun behind the moon, which kind of worked as well for a glow around the moon, but with a dark side as well. Perhaps 2 layers of thin cloud is better.