line_draw always draws with width=1

[nunodonato]

Operating system or device - Godot version: Godot 3(master), Linux

Issue description:
Using any width value in draw_line seems to be useless, the drawn line is always 1px(?) in width.

[akien-mga]

From IRC logs:

[17:33] <reduz_> nunod, in 3.0? not sure what to do about it, opengl 3.x does not support it
[17:33] <reduz_> nunod, as well as antialiasing, it's not supported either
[17:34] <reduz_> nunod, there probably should be a way around this, but i have no idea how to solve it
[17:34] <reduz_> for line width, a triangle could be used, which is not too bad
[17:34] <reduz_> well, two triangles
[17:34] <reduz_> but for antialiasing, no clue
[17:34] <nunod> reduz_, antialiasing seems to work fine
[17:34] <nunod> only the width is ignored
[17:35] <reduz_> i know, i mean antialiased thick lines
[17:39] <reduz_> nunod, it could be done with a shader without that much difficulty i guess, will have to see how to fix this eventually
[17:40] <reduz_> it must be fixable somehow
[17:40] <reduz_> i can think of ways to fix it, it's just not simple
[17:41] <Akien> reduz_: https://mattdesl.svbtle.com/drawing-lines-is-hard
[17:42] <Akien> Looks useful

[Zylann]

In Godot master it's possible to draw polygon-based thick lines with Line2D ;)

[nunodonato]

@Zylann I tried it, but can't get anything to show on the screen, thought it was broken. Any examples available?

[Zylann]

2D shapes themselves aren't broken, but this is: #7840 (comment)

Currently Line2D is just a Node2D with a list of points and some rendering options.
An example while it was WIP: https://www.youtube.com/watch?v=ikrJy9y7PEs

[nunodonato]

@Zylann so... it doesnt work at the moment, right? :)

[Zylann]

It works but you can't see it (in the issue I linked you can see the wireframe is correct), so... for the end user it doesn't works indeed, until that bug is fixed^^

[nunodonato]

so I guess its safe to close this, since the problem is basically in #7840 , right?

[Zylann]

I found SpatialMaterial has an option for line width, which I needed to make some debug lines more visible, but it has no effect. Should it be removed or are there plans to implement general purpose line rendering in both 2D and 3D?

[JohnMeadow1]

I consider this an regression since Godot 2.1.5 where I had this:

As for Godot 3.1. alpha 2 I have this :

Parameter Line Width for GeometryInstance does nothing, and is drawn as 1.

[akien-mga]

If not done already, it could probably be reimplemented in the GLES2 backend. According to @reduz in #8289 (comment) the usual method is not supported in GLES3, so it needs a different implementation (or it will be fixed only when properly implemented in the Vulkan backend).

[JohnMeadow1]

I have tested GLES2 on Godot 3.1 alpha 2, and it is the same.
So maybe we should drop or disable Line Width property in GeometryInstance for now?
It can be quite confusing, at current state.

[JohnMeadow1]

I have researched this a bit, and apparently this is not a bug.
According to some standards (sorry no source) rendering API should support rendering a line with at least 1px wide.
What I managed to dig up is that modern Opengl, and DirectX support line_width=1 and that is all.
This is probably because drawing a line as a geometry is usually used only for debuging (e.g. ray tracing) and wireframe rendering. For game purposes you will most of the time use textured quads, So this is why they might have dropped it.

Regarding Line Width property in GeometryInstance. If we want to render lines that are thicker, we need to write our own method for doing so. Line Width property is just not supported.
Unless I'm completely wrong, we might just need to drop Line Width property altogether, and think about Lines3D node.

As mentioned before drawing-lines-is-hard.

[blakeearth]

Draw_line's width parameter works as expected on my Windows machine running 3.0.6 Stable.

[Skaruts]

I'm having this problem in 3D (SpatialMaterial) in Godot 3.1.1, in both GLES2 and 3.

Should there be a separate issue for 3D?

[Calinou]

@Skaruts It seems the 3D issue has been mentioned above in this thread, no need to create a new issue.

[Skaruts]

@Calinou, indeed. I was just wondering.

Although, I'm also wondering how the editor's 3D gizmos are drawn. Because they have thick lines. Could you point me to the place in Godot's source where this happens? I've no clue where to find it, but I wonder if I might find a workaround there.

[Calinou]

@Skaruts It's in editor/spatial_editor_gizmos.cpp:

godot/editor/spatial_editor_gizmos.cpp

Line 203 in ad0d87b

void EditorSpatialGizmo::add_lines(const Vector<Vector3> &p_lines, const Ref<Material> &p_material, bool p_billboard) {

3D gizmos are drawn using procedural meshes generated using ArrayMesh. The add_lines() method above uses PRIMITIVE_LINES, which means it will still rely on OpenGL line drawing. However, some other kinds of "lines" (like the manipulator gizmo) use cubes or cylinders to emulate thick lines.

[Skaruts]

@Calinou interesting... I always thought the manipulators would be made with ImmediateGeometry.

Anyway, thanks a lot for pointing me to it.

[bluenote10]

For me (v3.1.2 stable, Linux) the width seems to be working, but it is the antialiased=true which doesn't seem to have any effect:

draw_line(Vector2(0, 0), Vector2(100, 200), Color(255, 0, 0), 3.0, true)

Is this expected / tracked by this or another issue?

[ScribbleFen]

For me (v3.1.2 stable, Linux) the width seems to be working, but it is the antialiased=true which doesn't seem to have any effect:

draw_line(Vector2(0, 0), Vector2(100, 200), Color(255, 0, 0), 3.0, true)

Is this expected / tracked by this or another issue?

I'm on v3.2 stable, Linux, having the same issue with anti-aliasing

[Calinou]

@bluenote10 Color(255, 0, 0) will create an extremely overbright red color (255 times brighter than a non-overbright red). This is why you can't see the antialiasing effect at all, even though it's technically there. You want to use Color(1, 0, 0) or Color8(255, 0, 0) instead 😉

[KoBeWi]

Can anyone still reproduce this bug in Godot 3.2.3 or any later release?

If yes, please ensure that an up-to-date Minimal Reproduction Project (MRP) is included in this report (a MRP is a zipped Godot project with the minimal elements necessary to reliably trigger the bug). You can upload ZIP files in an issue comment with a drag and drop.

[Skaruts]

@KoBeWi it's not working for me in 3D, netiher in GLES2 nor GLES3. Lines are all 1 width. However, GLES3 doesn't work well anyway in my old Radeon HD 4870, and I don't know if it's supposed to work in GLES2 to begin with.

I suppose I can try to find time to make an MRP, if this is supposed to work in GLES2. I won't fiddle with GLES3, as it stalls a lot on my end.

[Calinou]

However, GLES3 doesn't work well anyway in my old Radeon HD 4870, and I don't know if it's supposed to work in GLES2 to begin with.

GLES2 should work on old GPUs, but GLES3 isn't expected to work correctly indeed.

That said, unlike NVIDIA, AMD didn't implement line widths above 1 in their OpenGL line drawing code. This is why #43828 in 4.0 solves this problem entirely by not relying on OpenGL line drawing in the first place.

[Skaruts]

GLES2 should work on old GPUs, but GLES3 isn't expected to work correctly indeed.

I meant the line widths, though. But I guess you answered my question, and it's not supposed to work at all in my gfx card, at least in 3.x. (I'll be switching to an NVIDIA soon anyway.)

Although it's odd then, that I had line widths in Godot 2.

[YuriSizov]

I don't think this a problem in master, especially after fixes like #69851. Hardware limitation still applies of course, as described above.