Grease Pencil Erase: removes lines behind the view #50345

New Issue

Campbell Barton · 2016-12-31T08:22:28+01:00

Campbell Barton commented

2016-12-31 08:22:28 +01:00

In 2.78 (current master) the grease pencil erase tool doesn't check if the line is in front of the view or not.

In this file, use the eraser in the top viewport, (just erase over the whole view a few strokes). notice in the bottom viewport that lines are removed which aren't visible.

erase_behind_me.blend

Likely cause is gp_point_to_xy not passing V3D_PROJ_TEST_CLIP_NEAR flag.
view3d_point_depth also isn't correctly checking the depth - should probably call mul_project_m4_v3_zfac directly since ED_view3d_calc_zfac flips negative values - since its intended for tool code.

In 2.78 (current master) the grease pencil erase tool doesn't check if the line is in front of the view or not. In this file, use the eraser in the top viewport, (just erase over the whole view a few strokes). notice in the bottom viewport that lines are removed which aren't visible. [erase_behind_me.blend](https://archive.blender.org/developer/F425396/erase_behind_me.blend) ---- Likely cause is `gp_point_to_xy` not passing `V3D_PROJ_TEST_CLIP_NEAR` flag. `view3d_point_depth` also isn't correctly checking the depth - should probably call `mul_project_m4_v3_zfac` directly since `ED_view3d_calc_zfac` flips negative values - since its intended for tool code.

Campbell Barton commented

2016-12-31 08:22:28 +01:00

Changed status to: 'Open'

Campbell Barton commented

2016-12-31 08:22:28 +01:00

Added subscriber: @ideasman42

C.G.Vedant commented

2016-12-31 13:43:54 +01:00

Added subscriber: @Chipe1

C.G.Vedant commented

2016-12-31 15:55:52 +01:00

Looks like the problem is not limited to 'erase'. A newly drawn line also falls behind the view after certain zoom.

Antonio Vazquez commented

2016-12-31 19:08:31 +01:00

Added subscribers: @JoshuaLeung, @antoniov

Antonio Vazquez commented

2016-12-31 19:08:31 +01:00

@JoshuaLeung Could you look at this? I don't know this part of the code. Let me know if I can help you.

Joshua Leung commented

2017-01-02 04:27:57 +01:00

Hey Campbell, thanks for the tips!

IIRC, the eraser and the sculpt brushes don't currently take occlusion (geometry/zbuf stuff) into account when determining what to affect, though we should add support for that as it is quite useful to have.

Hey Campbell, thanks for the tips! IIRC, the eraser and the sculpt brushes don't currently take occlusion (geometry/zbuf stuff) into account when determining what to affect, though we should add support for that as it is quite useful to have.

Antonio Vazquez commented

2019-12-28 10:09:07 +01:00

Changed status from 'Confirmed' to: 'Archived'

Antonio Vazquez closed this issue

2019-12-28 10:09:07 +01:00

Antonio Vazquez self-assigned this 2019-12-28 10:09:07 +01:00

Antonio Vazquez commented

2019-12-28 10:09:07 +01:00

This is a design limitation

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Grease Pencil Erase: removes lines behind the view #50345