docs: public void setTexCoord(String texName, String texCoordAttr, String shaderVarName)
      {
          synchronized (textures)
          {
              GVRTexture tex = textures.get(texName);
  
              if (tex != null)
              {
                  tex.setTexCoord(texCoordAttr, shaderVarName);
              }
              else
              {
                  throw new UnsupportedOperationException("Texture must be set before updating texture coordinate information");
              }
          }
      }