Regression - depth buffer drawing go bonkers when selecting object on second collection #83482

New Issue

Jose Conseco · 2020-12-06T20:50:05+01:00

Jose Conseco commented

2020-12-06 20:50:05 +01:00

System Information
Operating system: Linux-5.8.18-1-MANJARO-x86_64-with-arch-Manjaro-Linux 64 Bits
Graphics card: GeForce GTX 1660 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.100

Blender Version
Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: 0f45cab862
Worked: 2.90

Short description of error
After drawing simple 3d lines with python script - depth buffer is drawn incorrectly when deselecting object that is placed on second collection.
Script itself is very generic - from blender gpu docs examples. It worked ok in all previous blender versions.

Linde_draw_depth_bug.mp4

Exact steps for others to reproduce the error

run script - it will draw 2 lines in 3d view for 8 seconds
if you select/deselect box which is placed on second layer/collection you will see those lines are drawn incorrectly on object deselect.

3d_view_lines_bug.blend

**System Information** Operating system: Linux-5.8.18-1-MANJARO-x86_64-with-arch-Manjaro-Linux 64 Bits Graphics card: GeForce GTX 1660 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.100 **Blender Version** Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: `0f45cab862` Worked: 2.90 **Short description of error** After drawing simple 3d lines with python script - depth buffer is drawn incorrectly when deselecting object that is placed on **second collection**. Script itself is very generic - from blender gpu docs examples. It worked ok in all previous blender versions. [Linde_draw_depth_bug.mp4](https://archive.blender.org/developer/F9480991/Linde_draw_depth_bug.mp4) **Exact steps for others to reproduce the error** - run script - it will draw 2 lines in 3d view for 8 seconds - if you select/deselect box which is placed on second layer/collection you will see those lines are drawn incorrectly on object deselect. [3d_view_lines_bug.blend](https://archive.blender.org/developer/F9480987/3d_view_lines_bug.blend)

Jose Conseco commented

2020-12-06 20:50:05 +01:00

Added subscriber: @JoseConseco

Robert Guetzkow commented

2020-12-07 11:41:44 +01:00

Added subscriber: @rjg

Robert Guetzkow commented

2020-12-07 11:41:44 +01:00

This is the same issue as reported in #82647 which is caused by a missing bgl.glDepthMask(bgl.GL_TRUE) in the script. Adding this before the bgl.glEnable(bgl.GL_DEPTH_TEST) to your script solves the problem.

This is the same issue as reported in #82647 which is caused by a missing `bgl.glDepthMask(bgl.GL_TRUE)` in the script. Adding this before the `bgl.glEnable(bgl.GL_DEPTH_TEST)` to your script solves the problem.

Robert Guetzkow commented

2020-12-07 11:41:53 +01:00

Closed as duplicate of #82647

Robert Guetzkow closed this issue

2020-12-07 11:41:53 +01:00

Jose Conseco commented

2020-12-07 12:31:17 +01:00

@rjg Did you actually test the change?Adding bgl.glDepthMask(bgl.GL_TRUE) changed nothing for me. I cant reopen the task now.
From what I googled: glDepthMask - enables writing to depth buffer. But in my bug report - the problem is - depth buffer is messed up when drawing with bgl on second collection only when no object is selected Maybe I'm missing somehting. Update code that still wont work:

import bpy
import gpu
import bgl
from gpu_extras.batch import batch_for_shader

coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)]
shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR')
batch = batch_for_shader(shader, 'LINES', {"pos": coords})


def draw():
    bgl.glEnable(bgl.GL_BLEND)
    bgl.glDepthMask(bgl.GL_TRUE)
    bgl.glEnable(bgl.GL_DEPTH_TEST)
    
    shader.bind()
    shader.uniform_float("color", (1, 1, 0, 0.6))
    batch.draw(shader)
    bgl.glDisable(bgl.GL_DEPTH_TEST)

    bgl.glDisable(bgl.GL_BLEND)

args = ()
handle=bpy.types.SpaceView3D.draw_handler_add(draw, args, 'WINDOW', 'POST_VIEW')
def in_5_seconds():
    print("Hello World")
    bpy.types.SpaceView3D.draw_handler_remove(handle, 'WINDOW')


bpy.app.timers.register(in_5_seconds, first_interval=8)

@rjg Did you actually test the change?Adding **bgl.glDepthMask(bgl.GL_TRUE)** changed nothing for me. I cant reopen the task now. From what I googled: glDepthMask - enables writing to depth buffer. But in my bug report - the problem is - depth buffer is messed up when drawing with bgl **on second collection only when no object is selected** Maybe I'm missing somehting. Update code that still wont work: ``` import bpy import gpu import bgl from gpu_extras.batch import batch_for_shader coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)] shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR') batch = batch_for_shader(shader, 'LINES', {"pos": coords}) def draw(): bgl.glEnable(bgl.GL_BLEND) bgl.glDepthMask(bgl.GL_TRUE) bgl.glEnable(bgl.GL_DEPTH_TEST) shader.bind() shader.uniform_float("color", (1, 1, 0, 0.6)) batch.draw(shader) bgl.glDisable(bgl.GL_DEPTH_TEST) bgl.glDisable(bgl.GL_BLEND) args = () handle=bpy.types.SpaceView3D.draw_handler_add(draw, args, 'WINDOW', 'POST_VIEW') def in_5_seconds(): print("Hello World") bpy.types.SpaceView3D.draw_handler_remove(handle, 'WINDOW') bpy.app.timers.register(in_5_seconds, first_interval=8) ```

Robert Guetzkow commented

2020-12-07 12:44:44 +01:00

@JoseConseco My bad, that was a misunderstanding and error on my part.

Robert Guetzkow commented

2020-12-07 12:46:36 +01:00

Changed status from 'Duplicate' to: 'Needs Triage'

Robert Guetzkow reopened this issue

2020-12-07 12:46:36 +01:00

Robert Guetzkow commented

2020-12-07 15:38:45 +01:00

Added subscriber: @fclem

Robert Guetzkow commented

2020-12-07 15:38:45 +01:00

My initial remark was nonsense since you don't attempt to clear the depth buffer. I've tested for a different use case than what you were attempting achieve.

The problem you're having happens when unselecting an object from a collection other than the first, while the first collection is hidden. The drawing issue can be avoided by setting the function for the depth test: bgl.glDepthFunc(bgl.GL_LEQUAL) .

import bpy
import gpu
import bgl
from gpu_extras.batch import batch_for_shader

coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)]
shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR')
batch = batch_for_shader(shader, 'LINES', {"pos": coords})


def draw():
    bgl.glDepthFunc(bgl.GL_LEQUAL)
    bgl.glEnable(bgl.GL_BLEND)
    bgl.glEnable(bgl.GL_DEPTH_TEST)
    shader.bind()
    shader.uniform_float("color", (1, 1, 0, 0.6))
    batch.draw(shader)
    bgl.glDisable(bgl.GL_DEPTH_TEST)
    bgl.glDisable(bgl.GL_BLEND)

handle = bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_VIEW')

def in_5_seconds():
    print("Hello World")
    bpy.types.SpaceView3D.draw_handler_remove(handle, 'WINDOW')


bpy.app.timers.register(in_5_seconds, first_interval=10)

@fclem this seems like a bug to me but my OpenGL is a little rusty. Could you check how this is supposed to work in 2.91? It seems that when the first collection is invisible, deselecting an object in another collection causes the comparison function for the depth buffer to be GL_GEQUAL or something with a similar effect.

My initial remark was nonsense since you don't attempt to clear the depth buffer. I've tested for a different use case than what you were attempting achieve. The problem you're having happens when unselecting an object from a collection other than the first, while the first collection is hidden. The drawing issue can be avoided by setting the function for the depth test: `bgl.glDepthFunc(bgl.GL_LEQUAL)` . ``` import bpy import gpu import bgl from gpu_extras.batch import batch_for_shader coords = [(1, 1, 1), (-2, 0, 0), (-2, -1, 3), (0, 1, 1)] shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR') batch = batch_for_shader(shader, 'LINES', {"pos": coords}) def draw(): bgl.glDepthFunc(bgl.GL_LEQUAL) bgl.glEnable(bgl.GL_BLEND) bgl.glEnable(bgl.GL_DEPTH_TEST) shader.bind() shader.uniform_float("color", (1, 1, 0, 0.6)) batch.draw(shader) bgl.glDisable(bgl.GL_DEPTH_TEST) bgl.glDisable(bgl.GL_BLEND) handle = bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_VIEW') def in_5_seconds(): print("Hello World") bpy.types.SpaceView3D.draw_handler_remove(handle, 'WINDOW') bpy.app.timers.register(in_5_seconds, first_interval=10) ``` @fclem this seems like a bug to me but my OpenGL is a little rusty. Could you check how this is supposed to work in 2.91? It seems that when the first collection is invisible, deselecting an object in another collection causes the comparison function for the depth buffer to be `GL_GEQUAL` or something with a similar effect.

Robert Guetzkow commented

2020-12-07 15:38:54 +01:00

Changed status from 'Needs Triage' to: 'Needs Developer To Reproduce'

Jose Conseco commented

2020-12-08 12:02:52 +01:00

bgl.glDepthFunc(bgl.GL_LEQUAL) - indeed fixed the problem, but I still think this is a bug. Its weird first collection works ok, and it depends if object is selected or not

Robert Guetzkow commented

2020-12-10 13:38:21 +01:00

Changed status from 'Needs Developer To Reproduce' to: 'Confirmed'

Robert Guetzkow commented

2020-12-10 13:38:21 +01:00

Since I can reproduce the problem and there doesn't seem to be any change in behavior documented in the release notes or manual, I will confirm this issue.

hujin commented

2021-06-15 03:03:21 +02:00

Added subscriber: @2046411367

Philipp Oeser removed the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Regression - depth buffer drawing go bonkers when selecting object on second collection #83482