Cannot get Blended Alpha to reliable stack in the correct order

Armory Engine
1

Hi,

I can’t get Blended Alpha to reliable stack in the correct order.

I have a character 2D cut out character and the minute I set up the blending for alpha over behaviour on both the head and the eyeballs, as well as giving them both access to read and write from depth, and I have alpha test off; it’s losing the natural Y axis depth set up in my scene in the way I have my objects stacked in front of the camera.

I have event tried sorting elements.

I just can’t get this to reliable sort blended alpha properly.

Can anyone guide me forward on this?

-S

2

I came up with a ‘A’ solution to this. It’s not an ideal one because it means additional draw calls.

To get the look of a Spine character in your game engine the only thing I can think of to reliably stack alpha blended materials is to keep the character in parts, use sorting index on each mesh and avoid batching the meshes. Then:

-Tick depth texture in the render settings
-Ensure ‘batch meshes’ is off.
-Under: Armory Render Path/Render:

  • Renderer: ‘Forward Clustered.’
  • Materials: (This can be set to solid for Spine-like behaviour)
  • Blending: ON: This must be on for alpha blend, multiply, add etc.
  • Depth Texture: ON.
  • Draw Order: Index (Per object setting)

-For each object, under: ‘Object Properties’ / ‘Armory Props’ ‘Sorting Index’;
Assign a independent ‘Sorting index value’. Then look at the materials settings.

-For each object’s materials settings, under ‘Armory Props’ settings:

  • Cast Shadow: OFF
  • Receive Shadow: OFF
  • Read Depth: ON
  • Draw Depth: ON
  • Alpha Test: OFF
  • Blending: ON

BLENDING (For regular Alpha over):

  • Source = SourceAlpha,
  • Destination = InverseSourceAlpha
  • Operation = Add
  • Source (Alpha) = One
  • Destination (Alpha) = Inverse Source Alpha
  • Operation (Alpha) = Add

What I’m interested in before I consider this properly solved:

Is there a way to batch models in geo nodes where the index is stored as an attribute and accessed to draw things in the right order?

Essentially, I still want to be able to batch meshes AND get my meshes ordered correctly.

For now I will continue on with my project.
Would love to hear from someone on this.

-S