Shader Help Thread

[Dr. Van Nostrand]

Ah I see... I've clearly got a lot to learn. I hadn't touched most of these newer features yet. Thanks again!

lol wow the effect is way too fast as I had it originally! Here's a more subtle version in case anyone else is looking for a simple underwater warp shader

[Pixel Eater]

lol wow the effect is way too fast as I had it originally!

Yeah I think I went cross-eyed the first time

[Pixel Eater]

I wonder if someone can explain how the alpha property works for texture shaders? It's always seemed non-linear to me and impossible to counteract. Something I've just tried doing is actually causing me to be suspicious it's a bug but I want to make sure I'm not missing something.

So I have a 3D floor with the line opacity property set to 254. I have the software fuzz shader being applied to it's texture, multiplying the pixels' alpha (ie. colour.a) by values between 0.1875 and 0.65625. But what I get are low alpha values being shunted to zero (or lower?) instead. Previously I've assumed it was my error and just abandoned projects until I can figure it out, only now I'm using someone else's proven code verbatim.



You can see the detail is greatly reduced in the bridge compared to the spectre even though they share identical code. Are we supposed to treat colour.a differently in custom shaders?

[Cherno]

Hello, I have a question regarding shaders in zDoom. First of all, I have writen my own shaders before in some Unity projects so the basic concepts are not new to me.

I would like to know if it's possible to have a material for a md3 model that shows it's bitmap texture mapped to the viewport, as opposed to being uv-mapped to the model's local vertices. So, if the model moves on screen, the triangle(s) in question would just show a different part of the texture. If you remember the "fake specular" effect in Alone in the Dark (for thing like metallic and reflective surfaces), you know what I'm talking about.

The effect can be seen here, in the small mirror item:

https://www.youtube.com/watch?v=9lWaQe8 ... .be&t=1497

Can this be done?

[Cherno]

I know that MD3s can use materials, but can they also use custom shaders?

[SPZ1]

Instead of making a new thread I'm bumping this one

I'm looking to make a shader to rotate a graphic at the center but have been unsuccessful. I tried modifying the shader that is in the wiki all sorts of ways but the results were just varied wave patterns. Is this even possible?