Godot: UVs are unusable if VisualServer doesn't also get a texture

[Zylann]

I am trying to draw geometry in 2D using VisualServer::get_singleton()->canvas_item_add_triangle_array, however I noticed that UVs are unusable in a shader unless you also specify a texture. That can be annoying if all you have is a procedural material that doesn't need a main texture. The workaround is then to put a dummy texture RID as an argument.
Is this subject to change in 3.0?

[bojidar-bg]

What's the status on this one for 3.0?

[reduz]

I don't think I understand it

On Sat, Jan 28, 2017 at 7:09 PM, Bojidar Marinov [e-mail]
wrote:

What's the status on this one for 3.0?

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[Zylann]

If there is no texture on the material of the thing you draw, using UVs doesn't work when using a custom shader.

[ghost]

First of all thank you for your report and sorry for the delay.

We released Godot 3.0 in January 2018 after 18 months of work, fixing many old issues either directly, or by obsoleting/replacing the features they were referring to.

We still have hundreds of issues whose relevance/reproducibility needs to be checked against the current stable version, and that's where you can help us.
Could you check if the issue that you described initially is still relevant/reproducible in Godot 3.0 or any newer version, and comment about it here?

For bug reports, please also make sure that the issue contains detailed steps to reproduce the bug and, if possible, a zipped project that can be used to reproduce it right away. This greatly speeds up debugging and bugfixing tasks for our contributors.

Our Bugsquad will review this issue more in-depth in 15 days, and potentially close it if its relevance could not be confirmed.

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[Zylann]

It still happens in Godot 3.0.2, if you attempt to draw a polygon for example. If you make a shader that makes use of UVs but doesn't need a texture, it still won't draw anything.

extends Node2D


func _draw():
    var points = PoolVector2Array()
    points.append(Vector2(0,0))
    points.append(Vector2(100,0))
    points.append(Vector2(100,100))
    points.append(Vector2(0,100))

    var colors = PoolColorArray()
    colors.append(Color(1,1,1,1))
    colors.append(Color(1,1,1,1))
    colors.append(Color(1,1,1,1))
    colors.append(Color(1,1,1,1))

    var uvs = PoolVector2Array()
    uvs.append(Vector2(0,0))
    uvs.append(Vector2(1,0))
    uvs.append(Vector2(1,1))
    uvs.append(Vector2(0,1))

    draw_polygon(points, colors, uvs)

ERROR: VisualServerCanvas::canvas_item_add_polygon: Condition ' uv_size != 0 && (uv_size != pointcount || !p_texture.is_valid()) ' is true.
   At: servers\visual\visual_server_canvas.cpp:668

UVsWithoutTexture.zip

[eon-s]

I think shaders need a texture to work, try with a ColorFrame, shaders won't work without a texture on it.

[Zylann]

@eon-s but my point is, main textures are useless when using a ShaderMaterial that doesn't use TEXTURE, and UVs should be accessible if the shader makes use of UV.

[akien-mga]

Cherry-picked for 3.0.7.