Metallic and roughness textures in PBR

Questions
,
1

Hi guys,

I would like to know if it’s possible to set separately the roughness and metallic textures in the PBRMetallicRoughnessMaterial class. As far as I can tell, the only way to use both textures is to merge them both and use the metallicRoughnessTexture attribute. The green channel is then used for roughness and the blue one for metallic.

Thank you for your help,
Yoann

2

I also posted about this in the past , it was not something babylon was interested to expose themselves so I resorted to adding this functionality at runtime myself , here is my function , but take note :

• It was specific to my usage and I didnt need to control metallic variations , so I just used the loaded roughness texture and white values for all other channels. If you want to control both you would need to read the current metallicTexture ( if it exists ) and write only the roughness to it. etc

• I stored/cached the texture I created onto the material to avoid running the code again if not needed , this could be a memory concern but again , it is a controlled environment and I know my usage of this will not cause issues for me.

That all said , the code should point you in the direction you need and you can makee any changes you require :

Object.defineProperty(PBRBaseMaterial.prototype, "roughnessTexture", {
    configurable: true,
    set: function (newValue) {
      if (this[newValue.name]) {
        this.metallicTexture = this[newValue.name];
        return;
      }
      let texBuff;
      newValue.readPixels().then((val) => {
        texBuff = val;
        for (let i = 0; i < texBuff.length; i += 4) {
          texBuff[i] = 255;
          texBuff[i + 2] = 255;
          texBuff[i + 3] = 255;
        }
        let dimention = Math.sqrt(texBuff.length / 4);
        this[newValue.name] = new RawTexture(texBuff, dimention, dimention, 5, scene, true, true);
        this.roughness = 1;
        this.useRoughnessFromMetallicTextureAlpha = false;
        this.useRoughnessFromMetallicTextureGreen = true;
        this.metallicTexture = this[newValue.name];
      });
    },
  });
3 Likes
3

Thank you for your suggestion. Will take some time to look at your code, and get back to you if I have any questions.