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Graphics artist needed

An exciting "new" option in FlightGear, that includes reflections, lightmaps, the particle system etc.. A lot is yet to be discovered/implemented!

Re: Graphics artist needed

Postby wlbragg » Mon Aug 08, 2016 5:07 am

This effect needs to be used wisely and only where appropriate. Look at Google and you will find this type of feature in real life is more frequent in rural areas. Most modern tracks are hard edged and just don't resemble the surrounding countryside.

One thing that might help is to limit the blending, don't blend the track house's yards, just vacant lots and unimproved areas.
Kansas and Ohio/Midwest scenery development.
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Re: Graphics artist needed

Postby Thorsten » Mon Aug 08, 2016 5:44 am

The overall blending is configurable, and the idea is indeed that chiefly the unoccupied spaces show through. It's a bit of art to get this work nicely for a particular texture combination, not all combinations look good.
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Re: Graphics artist needed

Postby Thorsten » Mon Aug 08, 2016 7:48 am

I've pushed a few more options for large cities.

Code: Select all
      <urban_blend type="int">0</urban_blend>
      <blend_bias type="float">0.4</blend_bias>
      <urban_domains type="int">0</urban_domains>
      <urban_domain_size type="float">1000.0</urban_domain_size>
      <urban_domain_fraction type="float">0.0</urban_domain_fraction>


urban_blend: should there be blending with a second texture - either appearing through the holes or mixed in via domains
blend_bias: should the shader do flat blending of the textures to get color values more similar?
urban_domains: should Voronoi noise be used to rotate parts of the texture sheets to avoid tiling in large urban areas?
urban_domain_size: size scale for the domains
urban_domain_fraction: if blending is on, should a fraction of the domains utilize the alternative texture?

(and the shader now recognizes steep gradients - which is sort of crucial in Rio to get Sugarloaf mountain...)
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Re: Graphics artist needed

Postby erik » Mon Aug 08, 2016 8:22 am

Excellent, blend_bias makes all the difference.

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Re: Graphics artist needed

Postby CaptB » Mon Aug 08, 2016 12:03 pm

Here's another cleaner version of town_europe_south.png to try out. This one had the predominant green areas deleted completely, the parks and close by green areas with partial transparency and buildings and roads with no transparency at all.

https://postimg.org/image/j77e07fo3/
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Re: Graphics artist needed

Postby vnts » Mon Aug 08, 2016 11:40 pm

Just wondering, is there anything to be gained by switching to HSV or similar space, setting hue for uncovered areas to be the same as the underlying terrain texture+any blending operations to SV, then switching back to RGB. The idea would be to preserve the saturation/intensity (high frequency) detail present in the urban texture, while helping blend in to the terrain.

I attempted to see if this makes a difference on the latest nightly, using quickly googled conversion code here, but nightly build for Windows appears to have issues. I'm not sure if this would help, or if there's a less performance intensive conversion.

Mapping hue intervals specified in regional defintions, might allow seasonal change or crop type change without losing detail.
erik wrote in Sun Aug 07, 2016 10:27 pm:I'm not sure yet. I do like the blending of the background color into the texture but the buildings themselves also get very dull.

In other words, the issue is usually urban objects would be expected to contrast with surrounding strongly? It depends what is it exactly that is visible on urban texture photos..

What is the albedo of urban roofs, roads and especially cars compared to surroundings? The dynamic range between urban and surroundings may be much too high, and HDR photos or processing by the artists may be responsible for contrast being visible in photos. Keeping the original texture intensity during blending working in HSV space may help (it may also be possible to do some HDR compensation, or even BDRF differences, now that surfaces can be separated). Just a thought.

Kind regards,
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Re: Graphics artist needed

Postby Thorsten » Tue Aug 09, 2016 6:28 am

Just wondering, is there anything to be gained by switching to HSV or similar space, setting hue for uncovered areas to be the same as the underlying terrain texture+any blending operations to SV, then switching back to RGB.


Been there, done it.

The processing requirements to do it are minimal, but the difficulty is really tagging the color range with sufficient precision. This works for 'clean' situations - for instance the backlight effect of panel labels in cockpits is based on such tagging, but there you're typically looking at high contrast (white labels on dark grey near-homogeneous background), but it does not work for a terrain texture.

You can code increasingly sophisticated tagging, but the processing requirements to simply blend with an underlying texture based on alpha are not huge.

Basically it's better to do all the area tagging offline (i.e. have an artist clean the texture) and not waste shader processing power to get the task done at much lower quality.
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