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By greenhybrid
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A new BRDF for picogen: The Height-Slang-Height-Value-Distorter

In this case I used a mean perlin-function again to produce those reflections.

Downloadable version: 1680*1050 pixels
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1680x1050px 1.17 MB
© 2008 - 2021 greenhybrid
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Chromattix's avatar
Wow, and this is a result of the program you are making yourself? looking amazing so far...I mean, how many can say that they made the entire digital art themselves INCLUDING the program used to make it? :lol: just keep at it 8-)
greenhybrid's avatar
Thanks man, much appreciated :)

It's often very difficult to tell non-programming-people what "I programmed the software behind that" means, and they only see the final image but not the work behind; so comments like yours are rare and highly motivating :D
lyc's avatar
both the land and water are looking good, now it's time to pay some attention to the flora :D need grass and trees instead of RGBs!
greenhybrid's avatar
Thanks mate :)

You will recognize I am working on 2d clouds at the moment. It's hard to get them look plausible ... while not keeping myself 100% inline with the roadmap the flora is definitely under the top 5 in my todo list ... when was it when I first promised the plants? uh oh, *runs*
lyc's avatar
heh, always behind on your schedule eh? me too ;)

clouds are pretty difficult, maybe go for the trees first since you anyway want to use all that l-system stuff? you'll need some sort of lod...
greenhybrid's avatar
oh i haven't implemented a single line of l-system code, yet. height-slang is totally unrelated.

but that reminds me, just yesterday i had an idea for another, more math oriented functional programming language, it goes like:

lsq(x,y,z) -> x*x + y*y + z*z
l(x,y,z) -> sqrt(lsq(x,y,z))
n(x,y,z) -> x/L, y/L, z/L ; with L ::= l(x,y,z)
main () -> echo (l (n (0.5,0.5,0.5)))


lod isn't too important to me (at the moment), as long as i can AA it all :P
lyc's avatar
zomg a part of me dies everytime i read "slang" :|

lod is important, but i suppose if you want ultra-reference images (why not use doubles eh?) then yeah it's the right thing to do. one day when you finally upgrade to a nehalem box you'll have your aa :D
greenhybrid's avatar
hmm i was to lazy to find some buzz-word for height-slang :|

no ultra-reference, really, i call it 'lazyness' *argh* :P

btw, i *am* using doubles. i switched to them when i first rendered terrain of size 200000.0f^2+; you wan't believe how much debugging and epsilon-tweaking i did, before realising it was inaccuracies in floating point.
lyc's avatar
"slang" as you use it (what does it mean anyway?) is the buzzword, tho i actually dunno anyone else who says it ;P
greenhybrid's avatar
"slang" as in "ugly (programming-)language" :D
yeah, i should get some other name, one that sounds funky but also shows that height-slang is somewhat esoteric.
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kram1032's avatar
If that actually could be, your reflections look somewhat lowres...
What's the hshvd? No hint on google^^

Very nice results, though :D
I love the sky and scattering :)
greenhybrid's avatar
Dankeschön :)

The "shader" is a modified brdf for specular reflections with an additional parameter, namely a function f(x,y) -> R. The "vertical" (or 'height', or often simply the y-coordinate) component of the reflection direction is simply multiplied with the output of that function. Of course this is a biased brdf in that it is not reversible, but then it's too easy to not be implemented :)
greenhybrid's avatar
but also biased, as in this form the brdf is not symmetric, and the energy throughput ignores physical laws :P

but i think users can live with that. i just have to look up the propaganda page to eliminate all words of "unbiased ray tracer" :D
kram1032's avatar
kram1032's avatar
"Indigo Renderer is a free, _physically-based unbiased_ render engine."
Pasternak's avatar
You are achieving some amazing results man :thumbsup:
greenhybrid's avatar
Thank you very much, hopefully more to come :D
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