koobas.hobune.stream
How to Bind 3rd (hidden) uv channel in shader?
its possible to assign uv-coords to a 3rd uv-channel (not in the docs) like so:
var uv1: Vector2[] = new Vector2[4];
uv1[0] = new Vector2(0, 0);
uv1[1] = new Vector2(1, 0);
...
mesh.uv1 = uv1;
but how can i Bind that in my shader? currently i bind like this:
BindChannels {
Bind "Vertex", vertex
Bind "texcoord", texcoord0
Bind "texcoord1", texcoord1
-- how to bind these 3rd coords here? --
}
or do you know any other trick to get more than 2 uv channels to work?
If you're going to use a fixed function shader, you may be able to get it to work by taking manual control of rendering. But it would be a big pain; you'd need to render, then update the UVs, then render again. Unity is not set up to deal with that gracefully. Avoid that, if you can stuff the other UVs into some other attribute (normal, tangent, uv1, uv2, color). You'll have to write a programmable shader for that, though.
thanks for your reply! actualy i could calculate the uv coords inside the shader but i have no experience with programmable shaders and wanted to avoid that - wouldnt it hit the performance? (targeting iOS/Android)
I doubt that you could actually do that; shaders need to be massively parallel operations. Your code above doesn't fit that profile. As for performance, it's exactly the opposite. If you don't use programmable shaders, your performance will suffer. Yes, Unity does a bad job at the moment in that regard, with their "mobile" shaders.
would it be possible to offset the primary uv-coords in later passes with values hidden in uv2? is there any command i could google for? thanks! - just discovered your youtube channel
$$anonymous$$atrix does it for fixed function. You don't actually need a full matrix, so you should use programmable shaders to save instructions, but it will work.
