How to change the size (u, v) of a texture for one face of a mesh?

[hit2501]

I can apply a texture to a complete exported model (lets say a dodecahedron) from Blender and change its size with vScale and uScale. But now I'm trying change the size of only 1 face of the dodecahedron, is there a way or sample to achieve this? It would be necessary to apply the texture for each mesh by separated?

Thank you all.

[Wingnut]

Hi hit, good to see you again.  I can TRY to answer this... probably wrong... but I will tell some things.

Let's playground-up and do some thinkin'.

https://www.babylonjs-playground.com/#2GXQ13#11

Ok, that's all the further I'M going.  The rest... scares me.  FaceUV's.  Phew.

http://doc.babylonjs.com/how_to/createbox_per_face_textures_and_colors#polyhedra

http://doc.babylonjs.com/playground/?code=CreatePolyhedron

Flat.  Flat is important... which is one parameter of the possible options of a CreatePolyhedron() call, I think.  Look at console.  After convert-to-flat, our dodec has many more verts.  I THINK... a flat-shaded mesh has THREE available UV's at EACH corner/vert-position.  This is because their are actually 3 verts at each corner-point, on a flat-shaded mesh.

And that... is what YOU need, I believe.  You want to affect the texture on ONE face of the dodec, but not affect other faces.  Without flat-shaded... adjusting the UV at ONE vert-point... would affect the texture of all faces that intersected at that vert-point.  You just want to affect one face, so you need a "private uv", right?  heh.  No affecting the neighbors. 

Understand the difference between faceUVs adjusting scale/size of a face texture AT CREATION TIME, versus adjusting it later, "live".

I think one way is easy, the other way, not so easy.  Let's ping @jerome, just because I know he LOVES being pinged.

That guy drives faceUV's amazingly well.  He sort-of invented them for BJS, I think. 

[dbawel]

@hit2501

This is not necessarily simple in your code. If it were me, I would unwrap your texture, and modify the texture and or most likely the UV mapping in your application. Then export, which is far faster and far less calculations - if doable at all for your needs.

DB

[NasimiAsl]

hi @hit2501

i have one solution 

https://www.babylonjs-playground.com/#UXCB15#45

step 1 make png and select your selected face on this and  cut it

make custom shader  and read texture 2 ways

   diffuseColor = texture2D(mainTexture,vDiffuseUV).rgb;   // main texture
 
   float specialFart = texture2D(colorpatern,vDiffuseUV).a;   // special face condition
 
   vec3 def2 = texture2D(mainTexture,vDiffuseUV*20.).rgb; // read new  texture by scale 20
   

and in final mix them

 diffuseColor =  diffuseColor*(specialFart)+def2*(1.-specialFart)  ;

 

[hit2501]

Thank you Nasimi I'll try it.

[NasimiAsl]

** just notice CustomMaterial Have special bug when you wanna update lights or something we can't fix it yet

[Wingnut]

13 hours ago, dbawel said:

This is not necessarily simple in your code. If it were me, I would unwrap your texture, and modify the texture and or most likely the UV mapping in your application. Then export, which is far faster and far less calculations - if doable at all for your needs.

Hi guys.  This, and some of the other ideas... are "done at creation time" ideas.

Hit2501... you haven't yet told us if/not you need to resize a face texture... AFTER creation/first-render (later, during game-play).

If you DO need to resize a face's texture... later... after creation, that requires a different kind of solution, I think.  *shrug*