TextureProgressBars Should Allow For Individual Material/Shaders On Each Texture

[TheNichKing]

Hello,

I've run into this issue a few times since Godot 3 but it would be really helpful if TextureProgressBars allowed you to set an individual shader/material on each texture. Right now, the shader/material provided by CanvasItem applies to the entire bar and all of its textures.

I've searched online and there are a great number of various levels of hacky solutions to accomplish these kinds of effects. Namely, a lot of people seem to be interested in applying a shader only to the progress texture alone. Many solutions I've seen either require the use of multiple Control/TextureRect/TextureProgressBar nodes or an entirely custom written solution that replicates most of the features of a TextureProgressBar just to expose the textures directly to the draw renderer, which seems inelegant and prone to a lot of bugs and issues to me.

I think having the ability to apply custom shaders/materials to each texture in the TextureProgressBar would make it a lot easier to make higher graphical fidelity texture bars. As an example, I could have a shader that gives a particular pattern to the progress texture while having another shader that gives a shine effect to the over or under textures. Given that display bars are a relatively common feature in most games (health bars, timer bars, load bars, progress bars, etc) and the number of people I've seen posting various forms of solutions, I think this would be a highly beneficial feature to the community.

[Calinou]

Each TextureProgressBar node is its own CanvasItem. Each CanvasItem can only have one shader applied at a time, so this isn't technically possible to my knowledge.