Passing atlas tile's coordinates to a shader

Unity Engine
1

Hi all,
I need to use a texture atlas in order to pack all textures and be able to using a single shared material for several object in my scene.
Actually what I’m working on it’s a shader for procedural texturing of building facades.

I successfully create the atlas and passed it to the shader:

this.texturesAtlasDomains = this.atlas.PackTextures(orderedTextureList.ConvertToArray(), 0,ATLAS_WIDTH);
...
this.material.SetTexture("atlas", this.atlas);

That works fine. Now, in order to make my shader works under unity, the coordinate returned from PackTextures should be available inside the shader ( I need to sample the right tile in the fragment shader, for this reason I need the offset of tiles inside the atlas)

Is there anyway to do that? I’m thinking of packing them inside a Texture2D, but I’m having some troubles to make it work. It seems also that I can’t pass an array of float to a shader through a shader lab property, right?

Does anyone has ever done something similar? Can anyone put me in the right direction?

thanks in advance

2

you can encode them an array of float in a texture ,there are pairs of func in UnityCg.cginc do that work

3

Thanks for the suggestion. Sorry but I’m not an expert in this field, that’s the first time I do such operations.
Could you kindly provide an example on how I can store properly a Rect (x,y,width,height) inside a texture from C#, and how to decode it from inside a cg shader?

4

I am a rookie too,:smile: