Thread

[digital fable]

I don't think you're going to get correct results by using the tangent space normal map before converting to tangent space

[fast ledge]

oh, woops. missed that

[digital fable]

Using a normal map as the lerp T doesn't really make much sense to me anyway

[fast ledge]

the texture sampler there isn't really supposed to be a normal map

it's supposed to define the amount of the effect

my goal is that black parts use the default normal and white parts use a normal that always faces the view

presumably with some interpolation in between if necessary

on closer inspection my approach indeed doesn't work quite right

my thinking in changing the tangent normal and not the object normal is that i still want to support a regular normal map on top of my effect

[digital fable]

I have no idea how a physically accurate retroreflective material would be presented, or if that's even possible with the non-photonic lighting calculations we have

I was cooking up an example of how I'm doing it but everything crashed so give me a moment

[fast ledge]

i''ve done this once before with a different approach where the shader targeted a specific vector to be the light's 'direction' and it calculated it's own emission based on that

that would only support one light source at a time though

i wanted to try a more versatile approach this time

[digital fable]

Well, you can use a custom function to grab nearby light sources, which is what a lot of toon shaders use for example

Probably even possible to use multi-pass shading to overlay retrorefective shading and the usual lit shading, though that's tricky

[fast ledge]

yeah, it sounds tricky

[digital fable]

I don't know if that'd be the "correct" way to do retroreflectivity either

In reality the eyes and cameras we see them with are still quite different from game camera rendering and exposure

As well as how photons behave

[fast ledge]

yeah

well i've gone back to the simple approach for now, which affects the whole object

it looks pretty good on this cube, which reflects brightly from the correct angle

these cat eyes also appear to be doing what i told them to do but just aren't very bright regardless 🤔

do you know how i might make them brighter?

perhaps i could boost their total color by some amount

[digital fable]

You can, if you use a HDR color with a high intensity or multiply the color above 1 by other means

But that's hacky and can result in very unpredictable brightnesses so I don't recommend that before you get the material looking generally right first

Remember that metallic and smoothness values are important too

[fast ledge]

oh i think i'm just stupid?

okay yeah i painted them black by mistake LOL

they look much better white.

[digital fable]

Blending with a normal map is as simple as this

[fast ledge]

when you lerp between two normal vectors, what happens? does the result rotate, or does it like go 'across the middle' as it were?

pretend this unit circle is a unit sphere

[digital fable]

I'm not sure!
Maybe the result should be normalized to be correct

Doesn't look any different

[fast ledge]

what does Triplanar node do?

[digital fable]

Projects a texture in world/object space
I use it for testing because it works even on meshes with no UV maps

[fast ledge]

oh, all right.

this should be all right?

i think so anyway.

[digital fable]

Normal map is of type default instead of normal

[fast ledge]

ah, i see

i wonder what that actually changes.

i always assumed the value from the texture could go straight in without adjustment

[digital fable]

Normal map textures use a different color space and have their color channels swapped about afaik so it's important for how they're sampled

wish i could make the cone of response narrower

This is what smoothness would do

And metallic too, to an extent

Smoother material makes direct reflections more intense, but more focused

[fast ledge]

is there a way to specify the default color of the sampler when there's no texture asset ?

[digital fable]

Yes, if you have a property you can specify a default

This is important for normal maps

[fast ledge]

mhm

thanks :)

thank you for all your lovely help

if i want to blend the affect in a texture i'd need to essentially...

lerp between the blended normal and the default normal i think

[digital fable]

You can't really "blend" normal vectors as such

[fast ledge]

ah, so it'd be kinda all or nothing?

[digital fable]

The average of two vectors will be pointing between the two directions

[fast ledge]

that doesn't sound good

the effect i want to see seems more like lerping between two possible output colors

[digital fable]

It won't look right, but it's an useful effect
I needed retroreflective clothing so I made a hacky solution that lerps between the usual normals and retroreflection by view angle

The effect "bends" rather than blends, but it looks reasonably okay, especially when smoothness is also lerped by angle

[fast ledge]

i see

[digital fable]

In the Lit shader we don't have access to output color really, as the lighting is calculated on just one normal

[fast ledge]

yeah, i guess it's not really a pixel shader

or a raster shader or however you would call it

i have another question

[digital fable]

My understanding is that calculating lighting more than once requires multiple passes, which is what the complex lit shader does with its clearcoat

[fast ledge]

oh, i see

[digital fable]

But that's unfamiliar area to me

[fast ledge]

this cat eye is painted red but is being totally drowned out by the white of the bright lamp

i've turned off bloom here

the diffuse color is red

[digital fable]

Metallic value?

[fast ledge]

0

[digital fable]

Try 1

Metallic materials tint reflected light by their base color

[fast ledge]

a 1 doesn't reflect very easily

irl i'd expect a red thing to only reflect red light and absorb other light

im not sure how to have that happen in pbr, i'm surprised it isn't just like that already tbh

increasing the metallic value seems to only have the effect of reducing the impact of the bright light in a total way

which makes it more red up close but impacts distant reflection negatively

[digital fable]

That's the difference between metallic and nonmetallic materials

This of course reduces the total reflected light because they rarely "convert" light energy into their own wavelength

[fast ledge]

hmm

that isn't going to work here because these aren't true retro reflectors

so they need as much help as they can get

[digital fable]

For me it works decently well

[fast ledge]

here's a comparison of metal 0 vs metal .95

[digital fable]

Try these and see if they work

Here's my metallic road paint retroreflectors vs nonmetallic

[fast ledge]

i don't think this worked how it was supposed to

o_0

[digital fable]

Is your project on URP?

[fast ledge]

i notice you're making the color HDR though, in the super red

no, it's on HDRP

[digital fable]

Ah, I see

[digital fable]

If you add a target for HDRP here it might work just like that

Though the scene's post processing or cameras probably would not

[digital fable]

In this image there are short red paint strips and long
The short ones cheat with a boosted HDR base color, but the long ones do not

I think both work decently

[fast ledge]

i tried by using the specular color workflow instead of metallic

it goes to white, curiously

[digital fable]

Specular workflow determines specular color from specular color, rather than from metallicness + albedo

[fast ledge]

that's right

but i set my specular color to be red, and yet it goes to white in the distance skjhbs

oh i fixed the distant but it still doesn't have the effect i was hoping for

[digital fable]

What seemed to cause the distance color problem?

[fast ledge]

i changed 'energy conserving specular' setting

can i make the total color HDR? how would i do that?

i want to cheat the same way yours are

[digital fable]

That would work with Boost values above 1

[fast ledge]

it doesn't appear to 😅

[digital fable]

Unless HDRP clamps it somehow

Energy conservation is what we would specifically not want in this situation

If you want a pure red, green or blue glow the color would need to be a pure shade of those colors
Increasing intensity in HDR color space will boost cyan, magenta and yellow tones more, ultimately towards white

Tonemapping often will further dull monochromatic RGB brightness

[fast ledge]

i think im stuck, then

it'll go into HDR ranges either from the boost or from a high power reflection but in both cases will trend to white ;-;

[digital fable]

I'm not familiar enough with HDRP to give more precise advice

[fast ledge]

i appreciate the help though!

[digital fable]

You're a lot closer to the goal than originally though ^^

[fast ledge]

yeah :)

i got a nice effect at distance

i just wish i could get the total color after all of this, and multiply that

[digital fable]

Looks really good already!

[fast ledge]

:)

im not sure if want i want to do next is supported.

cos all this stuff is like, affecting the normal and the albedo and stuff.

but next i want to get like the final result of the render and multiply that.

like that isn't a property of the pbr material but like, a raster technique

pbr expects me to use emissive color to do this sort of thing but that's not really what i want

if part of the surface got put in shadow it should stay black

[digital fable]

It may be possible but definitely not supported, especially with how HDRP does things

If you can find a way to multiply the base color unclamped, that would be well enough as it'd boost reflections which is the important thing here

[fast ledge]

the issue i'm observing with boost is that it looks like HDRP is definitely clamping the base and i don't know how to get it to stop

and this means that after it's multiplied, exactly 1 unit of the sum total comes from the bright reflection and the all other 9999 units are the ambient color

this is kind of annoying tbh

tbh i don't really understand "HDR" color in contrast with non-hdr color and i've kind of never understood it

i don't get the difference, i don't really know why people make it out like there's a difference

to me it just seems that a color is hdr if you decide not to arbitrarily clamp your maximum value to 1, and that's it.

what i want to do is perfectly possible in mathematics and computer graphics but someone at unity arbitrarily decided that this node should clamp and now i'm stuck

[digital fable]

Basically so
Colors usually are 0 to 1 in each channel, as most programs, standards and formats support just that
HDR color is that multiplied by intensity float
Nothing fancier

[digital fable]

I assume it was clamped because HDRP aims for graphical realism and physical accuracy above all else, and albedo values above 1 break that physical accuracy

[fast ledge]

they do, yes

in theory if i do this i can make the cat eye reflect more light than actually entered it

but for my purposes, this is exactly what i want, and im tbh pretty annoyed that i'm not allowed to do it

[digital fable]

It is frustrating!

But it's a bit of a theme
Like 90% of all rules we work with in these programs are arbitrary, often intended to help someone at the unintended effect of making something else harder

There's some hope that upcoming block shaders will give us control over individual parts of the existing Lit shaders

@mint owl Do you happen to know if there's a way to use "above 1" Base Color in HDRP, or some other way to boost reflected light above its normal intensity in the Lit shader, since it seems to be clamped to 1 for physical accuracy
(or if that variable could be unclamped in the future)

A workaround that comes to my mind could be to render the material twice, using a custom pass or the like, another time with an identical shader that's additively transparent
But that seems like a very roundabout way

[fast ledge]

my ultimate goal is to make these more visible at a distance and / or more intense in their albedo color

[mint owl]

No way to have the base color > 1, like you've said, it's clamped.

I think that the only way to do retro-reflection is to use a custom lighting, which HDRP doesn't support :/

[digital fable]

Thanks
Retroreflection works fine on its own, but being able to boost it is useful extra

[mint owl]

"Ugly" solution : re-render the objects with transparent shader, read from the color buffer and output the same value multiplied by constant