Grease pencil sculpt stroke size not displayed in the viewport. #47783

New Issue

Alexey Khoral · 2016-03-13T20:20:19+01:00

Alexey Khoral commented

2016-03-13 20:20:19 +01:00

System Information
Xubuntu 14.04 x64 3.19.0-51-generic

Blender Version
Broken: 2.77 RC1, RC2

Short description of error
Grease pencil sculpt stroke size not displayed in the viewport, but i can see white circle on bottom panel. See include screen.

**System Information** Xubuntu 14.04 x64 3.19.0-51-generic **Blender Version** Broken: 2.77 RC1, RC2 **Short description of error** Grease pencil sculpt stroke size not displayed in the viewport, but i can see white circle on bottom panel. See include screen. ![gpenscil.png](https://archive.blender.org/developer/F289913/gpenscil.png)

Alexey Khoral commented

2016-03-13 20:20:19 +01:00

Changed status to: 'Open'

Alexey Khoral commented

2016-03-13 20:20:19 +01:00

Added subscriber: @allkhor

blender-admin commented

2016-03-13 20:20:19 +01:00

#47878 was marked as duplicate of this issue

Joshua Leung commented

2016-03-13 22:00:05 +01:00

Added subscriber: @JoshuaLeung

Joshua Leung commented

2016-03-13 22:00:05 +01:00

Does this happen for any other types of brush (eg go eraser, sculpt brush, particle edit brush)?

From the screenshot it looks like you've got Only Render enabled for that viewport?

Please include details about your graphics card as this could be an opengl related issue.

Does this happen for any other types of brush (eg go eraser, sculpt brush, particle edit brush)? From the screenshot it looks like you've got Only Render enabled for that viewport? Please include details about your graphics card as this could be an opengl related issue.

Joshua Leung self-assigned this 2016-03-13 22:00:21 +01:00

Julian Eisel commented

2016-03-13 22:13:36 +01:00

Added subscriber: @JulianEisel

Julian Eisel commented

2016-03-13 22:13:36 +01:00

Agree that information here could be better, anyhow, I can easily recreate with any brush using GPencil sculpt modal.

Joshua Leung commented

2016-03-14 02:38:28 +01:00

@JulianEisel: I can't reproduce this issue here (Windows 8.1 + Nvidia GeForce 740M)

Joshua Leung was unassigned by Julian Eisel

2016-03-14 02:51:43 +01:00

Julian Eisel self-assigned this 2016-03-14 02:51:43 +01:00

Julian Eisel commented

2016-03-14 02:51:43 +01:00

Yuk! Can investigate tomorrow on my machine in the institute then (Linux, Nvidia GTX260 or something like that :S)

Alexey Khoral commented

2016-03-14 03:22:49 +01:00

My hardware: Video card: Nvidia GTX 750ti 2gb, driver 352.79, cpu core i5 750, 8 GB ram...
Eraser, sculpt brush and other brushs display correct. It's not only render mode, you cant's see mouse cursor, because xubuntu don't grub it when i make screenshot.

Tested on blender-softwaregl issue reproduced here.

My hardware: Video card: Nvidia GTX 750ti 2gb, driver 352.79, cpu core i5 750, 8 GB ram... Eraser, sculpt brush and other brushs display correct. It's not only render mode, you cant's see mouse cursor, because xubuntu don't grub it when i make screenshot. Tested on blender-softwaregl issue reproduced here.

Alexey Khoral commented

2016-03-14 03:37:12 +01:00

Tested on windows 8.1 x32, video integrated intel, some here.

Tested on windows 8.1 x32, video integrated intel, some here. ![gpencil_windows.PNG](https://archive.blender.org/developer/F290234/gpencil_windows.PNG)

perfection cat commented

2016-03-14 08:57:30 +01:00

Added subscriber: @sindra1961

perfection cat commented

2016-03-14 08:57:30 +01:00

windows 10 pro 64bits
NVidia GTX960 + GT730
version: 2.77 (sub 0), hash: 34fe03c

windows 10 pro 64bits NVidia GTX960 + GT730 version: 2.77 (sub 0), hash: 34fe03c ![Grease Pencil2.png](https://archive.blender.org/developer/F290456/Grease_Pencil2.png) ![Grease Pencil.png](https://archive.blender.org/developer/F290458/Grease_Pencil.png)

Joshua Leung commented

2016-03-14 11:11:53 +01:00

@sindra1961 Thanks for the screenshots. I can now reproduce the bug, and I think I might know why it happens :)

Julian Eisel commented

2016-03-14 22:10:54 +01:00

Cheeesis, this is tricky. Spent some hours investigating, here's what's going on (if I'm not mistaken):

Selecting the item from the menu makes the ui-handler return WM_UI_HANDLER_BREAK which again makes the wm-handler return WM_HANDLER_BREAK.
Because of this, wm_event_do_handlers doesn't call the functions needed to set the right context for drawing the cursors (ED_screen_set_subwinactive & wm_paintcursor_test).
To trigger an update of the cursor, it's usually enough to send a mouse move event, which is done in fact.
Issue is though, that now the modal operator for stroke sculpting runs, and - unlike other modal operators - it doesn't return OPERATOR_PASS_THROUGH for the mouse move event added (nor for any other mouse move event).
This means, as long as the operator runs, the wm_event_do_handlers never calls the functions for updating the cursor context.
The wrong context causes a glScissor call for the wrong region.

Possible ways to fix this:

Let stroke sculpt operator pass the first event - P334
Always return OPERATOR_PASS_THROUGH on mouse move during stroke sculpting and use paintcursor poll to check for correct region (to lazy to write patch, should work though ;) )
Always let WM call the cursor context update functions after cursor was changed (a bit ugly and just another event system hack, but technically it would be a correct fix) - P333
Always let WM call the cursor context update on mouse move - P335 (also a correct fix - here we had to add a paintcursor poll check for correct region too though)

While investigating I also noticed that the return values in gpsculpt_brush_modal are managed in a pretty odd way. For example it's assuming that view rotation is set to middle mouse button. The operator should return OPERATOR_PASS_THROUGH by default and only block events it really uses (doing that would basically include #2.)

BTW: Invoking the stroke sculpt operator from the search menu outside of the main 3D view region causes a crash :| Instead of using CTX_wm_region to get the region we should search for a region that supports gpencil drawing (we'd also need that for #2.).

Cheeesis, this is tricky. Spent some hours investigating, here's what's going on (if I'm not mistaken): * Selecting the item from the menu makes the ui-handler return `WM_UI_HANDLER_BREAK` which again makes the wm-handler return `WM_HANDLER_BREAK`. * Because of this, `wm_event_do_handlers` doesn't call the functions needed to set the right context for drawing the cursors (`ED_screen_set_subwinactive` & `wm_paintcursor_test`). * To trigger an update of the cursor, it's usually enough to send a mouse move event, which is done in fact. * Issue is though, that now the modal operator for stroke sculpting runs, and - unlike other modal operators - it doesn't return `OPERATOR_PASS_THROUGH` for the mouse move event added (nor for any other mouse move event). * This means, as long as the operator runs, the `wm_event_do_handlers` never calls the functions for updating the cursor context. * The wrong context causes a `glScissor` call for the wrong region. Possible ways to fix this: - Let stroke sculpt operator pass the first event - [P334](https://archive.blender.org/developer/P334.txt) - Always return `OPERATOR_PASS_THROUGH` on mouse move during stroke sculpting and use paintcursor poll to check for correct region (to lazy to write patch, should work though ;) ) - Always let WM call the cursor context update functions after cursor was changed (a bit ugly and just another event system hack, but technically it would be a correct fix) - [P333](https://archive.blender.org/developer/P333.txt) - Always let WM call the cursor context update on mouse move - [P335](https://archive.blender.org/developer/P335.txt) (also a correct fix - here we had to add a paintcursor poll check for correct region too though) While investigating I also noticed that the return values in `gpsculpt_brush_modal` are managed in a pretty odd way. For example it's assuming that view rotation is set to middle mouse button. The operator should return `OPERATOR_PASS_THROUGH` by default and only block events it really uses (doing that would basically include #2.) BTW: Invoking the stroke sculpt operator from the search menu outside of the main 3D view region causes a crash :| Instead of using `CTX_wm_region` to get the region we should search for a region that supports gpencil drawing (we'd also need that for #2.).

Julian Eisel commented

2016-03-14 22:46:17 +01:00

This is also reproducible from other editors btw, e.g. call stroke sculpting from search menu in node editor toolbar.

We could fix the crash by ensuring the operator is only called in the main region in case of a 3D View, but that would make it inconsistent with other areas (wouldn't be a big annoyance though).

I'd propose we continue as follows:

Add bool ED_region_supports_gpencil(ARegion *ar)
Use it for implementing #4
Use it for fixing crash
Cleanup gpsculpt_brush_modal for a more streamlined event handling

This is also reproducible from other editors btw, e.g. call stroke sculpting from search menu in node editor toolbar. We could fix the crash by ensuring the operator is only called in the main region in case of a 3D View, but that would make it inconsistent with other areas (wouldn't be a big annoyance though). I'd propose we continue as follows: * Add `bool ED_region_supports_gpencil(ARegion *ar)` * Use it for implementing #4 * Use it for fixing crash * Cleanup `gpsculpt_brush_modal` for a more streamlined event handling

Joshua Leung commented

2016-03-22 00:35:38 +01:00

Added subscriber: @mendio