Viewport: edge drawing artefacts (hidden edges are partially visible) #66008

New Issue

artem ivanov · 2019-06-22T00:46:39+02:00

artem ivanov commented

2019-06-22 00:46:39 +02:00

System Information
Operating system: Windows 10
Graphics card: GeForce GTX 1070

Blender Version
Broken: version: 2.80, branch: master, commit date: 2019-06-19 18:29, hash: d30f72dfd8

Short description of error
About 1.5-2px of the hidden edges are drawn in the viewport under certain angles (see screenshots below).
This artefact is more noticeable if "viewport rendered" with 400% scale (properties -> output panel -> dimensions -> %).
Interface resolution scale and viewport anti-aliasing settings have no effect on this issue.
This bug is not specific to the attached .blend and can be reproduced on my side with pretty much any geometry.

With default View -> Focal Length = 50mm it is slightly noticeable, but with Focal Length = 250mm it is clearly visible.

edge_draw_bug.blend

**System Information** Operating system: Windows 10 Graphics card: GeForce GTX 1070 **Blender Version** Broken: version: 2.80, branch: master, commit date: 2019-06-19 18:29, hash: `d30f72dfd8` **Short description of error** About 1.5-2px of the hidden edges are drawn in the viewport under certain angles (see screenshots below). This artefact is more noticeable if "viewport rendered" with 400% scale (properties -> output panel -> dimensions -> %). Interface resolution scale and viewport anti-aliasing settings have no effect on this issue. This bug is not specific to the attached .blend and can be reproduced on my side with pretty much any geometry. With default View -> Focal Length = 50mm it is slightly noticeable, but with Focal Length = 250mm it is clearly visible. ![image.png](https://archive.blender.org/developer/F7443533/image.png) ![image.png](https://archive.blender.org/developer/F7443590/image.png) ![image.png](https://archive.blender.org/developer/F7443592/image.png) ![image.png](https://archive.blender.org/developer/F7443257/image.png) ![image.png](https://archive.blender.org/developer/F7443266/image.png) [edge_draw_bug.blend](https://archive.blender.org/developer/F7443602/edge_draw_bug.blend)

artem ivanov commented

2019-06-22 00:46:39 +02:00

Added subscriber: @ixd

artem ivanov commented

2019-06-22 06:16:00 +02:00

Possible fix: tweaking zoffset value for edges. But there is a tradeoff: the lower the zoffset, the higher the zfighting.
But on the screenshot below (Focal Len 250mm) zfighting artifacts of zoffset = 0.51f is almost the same as with the default 1.0.

With zoffset <= 0.6f and View -> Focal Length = 50 (default) edge artifacts are disappeared for me. Edit: this works only for 90+deg lines. Smaller angles (more complex geometry) require smaller zoffset values => more zfighting.

P1010: #66008: possible fix

diff --git a/source/blender/draw/modes/edit_mesh_mode.c b/source/blender/draw/modes/edit_mesh_mode.c
index eca60c291fe..d6b6f2ca7f9 100644
--- a/source/blender/draw/modes/edit_mesh_mode.c
+++ b/source/blender/draw/modes/edit_mesh_mode.c
@@ -332,7 +332,7 @@ static void EDIT_MESH_engine_init(void *vedata)
     /* Create view with depth offset */
     stl->g_data->view_faces = (DRWView *)DRW_view_default_get();
     stl->g_data->view_faces_cage = DRW_view_create_with_zoffset(draw_ctx->rv3d, 0.5f);
-    stl->g_data->view_edges = DRW_view_create_with_zoffset(draw_ctx->rv3d, 1.0f);
+    stl->g_data->view_edges = DRW_view_create_with_zoffset(draw_ctx->rv3d, 0.6f);
     stl->g_data->view_verts = DRW_view_create_with_zoffset(draw_ctx->rv3d, 1.5f);
   }
 }

zfighting was tested with this file:
edge_draw_bug_ztest.blend

Edit: Added another case: small angles

Possible fix: tweaking zoffset value for edges. But there is a tradeoff: the lower the zoffset, the higher the zfighting. But on the screenshot below (Focal Len 250mm) zfighting artifacts of `zoffset = 0.51f` is almost the same as with the default 1.0. ![image.png](https://archive.blender.org/developer/F7443916/image.png) With `zoffset <= 0.6f` and View -> Focal Length = 50 (default) edge artifacts are disappeared for me. *Edit: this works only for 90+deg lines. Smaller angles (more complex geometry) require smaller zoffset values => more zfighting.* [P1010: #66008: possible fix](https://archive.blender.org/developer/P1010.txt) ```diff diff --git a/source/blender/draw/modes/edit_mesh_mode.c b/source/blender/draw/modes/edit_mesh_mode.c index eca60c291fe..d6b6f2ca7f9 100644 --- a/source/blender/draw/modes/edit_mesh_mode.c +++ b/source/blender/draw/modes/edit_mesh_mode.c @@ -332,7 +332,7 @@ static void EDIT_MESH_engine_init(void *vedata) /* Create view with depth offset */ stl->g_data->view_faces = (DRWView *)DRW_view_default_get(); stl->g_data->view_faces_cage = DRW_view_create_with_zoffset(draw_ctx->rv3d, 0.5f); - stl->g_data->view_edges = DRW_view_create_with_zoffset(draw_ctx->rv3d, 1.0f); + stl->g_data->view_edges = DRW_view_create_with_zoffset(draw_ctx->rv3d, 0.6f); stl->g_data->view_verts = DRW_view_create_with_zoffset(draw_ctx->rv3d, 1.5f); } } ``` zfighting was tested with this file: [edge_draw_bug_ztest.blend](https://archive.blender.org/developer/F7443925/edge_draw_bug_ztest.blend) *Edit: Added another case: small angles* ![image.png](https://archive.blender.org/developer/F7445506/image.png)

Sebastian Parborg commented

2019-06-24 11:33:54 +02:00

Added subscribers: @fclem, @ZedDB

Clément Foucault was assigned by Sebastian Parborg

2019-06-24 11:33:54 +02:00

Sebastian Parborg commented

2019-06-24 11:33:54 +02:00

@fclem any input on this?

Clément Foucault commented

2019-06-27 17:00:56 +02:00

The issue was present in 2.79. But the issue seems to have double in proportion. I don't know why exactly because we use the same function for the bias.

blender-admin commented

2019-07-08 14:18:12 +02:00

This issue was referenced by 7767e080a0

This issue was referenced by 7767e080a03174d0538444a82d3d7baf72d7b843

Clément Foucault commented

2019-07-08 18:19:18 +02:00

Changed status from 'Open' to: 'Resolved'

Clément Foucault closed this issue

2019-07-08 18:19:18 +02:00

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Viewport: edge drawing artefacts (hidden edges are partially visible) #66008