When there are multiple textures in effect, depending on the Texture Blend Mode in use, it may be important to control the order in which the textures apply. For instance, although Modulate mode and Add mode are order-independent, texture order makes a big difference to Decal mode, Replace mode, and Blend mode.
To specify the texture order, use
TextureStage.setSort() on one or more of your TextureStages. If you do not specify a sort value, the default sort value is 0. When the geometry is rendered, all of the textures are rendered in increasing order of sort value, such that the largest sort value is rendered on top. Thus, if you want to use Decal mode, for instance, to apply a texture on top of a lower texture, it would be a good idea to use setSort() to give a higher sort value to your decal texture.
Also, since some hardware might not be able to render all of the TextureStages that you have defined on a particular node, Panda provides a way for you to specify which texture(s) are the most important. Use
TextureStage.setPriority() for this.
The priority value is only consulted when you have applied more TextureStages to a particular node than your current hardware can render. In this case, Panda will select the n textures with the highest priority value (and then sort them in order by the setSort() value). Between two textures with the same priority, Panda will prefer the one with the lower sort value. The default priority is 0.