Instance uniforms are not implemented for 2D shaders

[Knand1861]

Godot version

4.11 alpha

System information

Windows 11

Issue description

Instance keyword makes hints disappear and makes GDscript helpless in controlling the value in any way [It defaults to 0, as for float];
Delete instance keyword, and it works again.

Steps to reproduce

shader:

shader_type canvas_item;
instance uniform float opacity :hint_range(0.0, 1.0, 0.1)=0.5;

void fragment(){
	vec4 color = texture(TEXTURE,UV);
	color.a-=opacity;
	COLOR = color;
}

sprite with an area2d and collisionshape:

extends Sprite2D


func _on_area_2d_area_entered(area):
	material.set_shader_param("opacity",1.0)

[Calinou]

I guess this is because the editor isn't aware of per-instance uniforms. These were likely designed to be changed via code first and foremost.

Edit: The issue is that per-instance uniforms (and likely global uniforms) aren't implemented for use in 2D (canvas_item) shaders yet. They only work with 3D (spatial) shaders.
As per the other linked issues, can you test this in a 3D (spatial) shader instead of a 2D (canvas_item) shader?

[clayjohn]

Edit: The issue is that per-instance uniforms (and likely global uniforms) aren't implemented for use in 2D (canvas_item) shaders yet.

Just to note, Global Uniforms should work with every shader type including sky, particles, and fog. Per-instance uniforms are a different story (although they could likely be made to work with FogVolumes)

Instance keyword makes hints disappear and makes GDscript helpless in controlling the value in any way [It defaults to 0, as for float];

Instance Uniforms belong to the GeometryInstance, not to the shader, so you don't set them using material.set_shader_param() you set them with mesh_instance.set_shader_instance_uniform()

[SmartySmart702]

Instance Uniforms belong to the GeometryInstance, not to the shader, so you don't set them using material.set_shader_param() you set them with mesh_instance.set_shader_instance_uniform()

Had some trouble debugging this issue because I used material.set_shader_param(). This should trigger a warning in the debugger.

[KoBeWi]

I tried :<
KoBeWi@9220e5e
The uniforms show up in the inspector, but in a wrong place and editing them has no effect. Also the implementation is trash. But maybe it will be useful as a starting point for someone.

[riazey]

This is still a major issue in the beta, I noticed it wasn't included in the 4.0 roadmap was it decided that having this new shader feature be unavailable for 2D in the full 4.0 release?

I might be blind so just double checking cuz I was super looking forward to it for my color palette* swapping xD

[Calinou]

I noticed it wasn't included in the 4.0 roadmap was it decided that having this new shader feature be unavailable for 2D in the full 4.0 release?

We don't know whether this feature will be added in time for 4.0. It all depends on a motivated contributor being able to implement this 🙂

[Praytic]

What is the workaround for instance uniforms for canvas_item shaders? We have like 600 instances of duplicated shader code...