inverted GL_DEPTH_TEST behavior depending on object selection or presence of non-geo object #82843

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MACHIN3 · 2020-11-19T14:18:45+01:00

MACHIN3 commented

2020-11-19 14:18:45 +01:00

System Information
Operating system: Linux-4.15.0-117-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 435.21

Blender Version
Broken: version: 2.91.0 Beta, branch: master, commit date: 2020-11-18 18:54, hash: ad58999b0d
Worked: 2.90.1

Short description of error
Drawing anything using the GPU shader module and using bgl.GL_DEPTH_TEST produces odd behavior in 2.91.
In the example below bgl.GL_DEPTH_TEST is enabled to have geometry occlude what is drawn. This worked fine in the past.

In 2.91, this only works if geometry is selected(and so the selection outline overlay is drawn). With the object not selected, the depth test occlusion will behave inverted: Drawing when occluded and not drawing when revealed.

In addition to selecting, having an empty or other non-geo objects present will also correct this behavior.

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

def draw():
    shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR')
    shader.bind()
    shader.uniform_float("color", (1, 0, 0, 0.5))

    bgl.glEnable(bgl.GL_DEPTH_TEST)

    bgl.glPointSize(10)

    batch = batch_for_shader(shader, 'POINTS', {"pos": [Vector((0, 0, 1))]})
    batch.draw(shader)
    

bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_VIEW')
bpy.context.area.tag_redraw()

demo video
inverted GL_DEPTH_TEST behavior depending on object selection or non-geo object presence.blend

Exact steps for others to reproduce the error

open the blend file in a recent 2.91 beta build
run the script, a red dot will be drawn in the 3d view (move the viewport to force the area to redraw)
the dot should be occluded, but isn't
select the cube and it will be occluded, move it to reveal the dot
deselect the cube and the dot will be hidden, even though its outside the cube now
create an empty and the dot will again be drawn when outside the cube, and hidden when occluded by it, no matter what your selection is, as you'd expect

**System Information** Operating system: Linux-4.15.0-117-generic-x86_64-with-debian-buster-sid 64 Bits Graphics card: GeForce GTX 1050/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 435.21 **Blender Version** Broken: version: 2.91.0 Beta, branch: master, commit date: 2020-11-18 18:54, hash: `ad58999b0d` Worked: 2.90.1 **Short description of error** Drawing anything using the GPU shader module and using `bgl.GL_DEPTH_TEST` produces odd behavior in 2.91. In the example below `bgl.GL_DEPTH_TEST` is enabled to have geometry occlude what is drawn. This worked fine in the past. In 2.91, this only works if geometry is selected(and so the selection outline overlay is drawn). With the object not selected, the depth test occlusion will behave inverted: Drawing when occluded and not drawing when revealed. In addition to selecting, having an empty or other non-geo objects present will also correct this behavior. ``` import bpy from mathutils import Vector import gpu from gpu_extras.batch import batch_for_shader import bgl def draw(): shader = gpu.shader.from_builtin('3D_UNIFORM_COLOR') shader.bind() shader.uniform_float("color", (1, 0, 0, 0.5)) bgl.glEnable(bgl.GL_DEPTH_TEST) bgl.glPointSize(10) batch = batch_for_shader(shader, 'POINTS', {"pos": [Vector((0, 0, 1))]}) batch.draw(shader) bpy.types.SpaceView3D.draw_handler_add(draw, (), 'WINDOW', 'POST_VIEW') bpy.context.area.tag_redraw() ``` [demo video ](https://www.youtube.com/watch?v=oy3PDDSdSdY) [inverted GL_DEPTH_TEST behavior depending on object selection or non-geo object presence.blend](https://archive.blender.org/developer/F9325495/inverted_GL_DEPTH_TEST_behavior_depending_on_object_selection_or_non-geo_object_presence.blend) **Exact steps for others to reproduce the error** * open the blend file in a recent 2.91 beta build * run the script, a red dot will be drawn in the 3d view (move the viewport to force the area to redraw) * the dot should be occluded, but isn't * select the cube and it will be occluded, move it to reveal the dot * deselect the cube and the dot will be hidden, even though its outside the cube now * create an empty and the dot will again be drawn when outside the cube, and hidden when occluded by it, no matter what your selection is, as you'd expect

MACHIN3 commented

2020-11-19 14:18:45 +01:00

Added subscriber: @MACHIN3

Piotr commented

2020-11-19 18:37:21 +01:00

Added subscriber: @Pinnhead

Piotr commented

2020-11-19 18:37:21 +01:00

version: 2.91.0 Beta, branch: master, commit date: 2020-11-18 18:54, hash: ad58999b0d, type: Release
build date: 2020-11-19, 00:04:58
platform: Windows

Exactly the same behavior as described.

version: 2.91.0 Beta, branch: master, commit date: 2020-11-18 18:54, hash: ad58999b0d46, type: Release build date: 2020-11-19, 00:04:58 platform: Windows Exactly the same behavior as described.

Germano Cavalcante commented

2020-11-20 15:34:45 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-11-20 15:34:45 +01:00

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

Germano Cavalcante commented

2020-11-20 15:34:45 +01:00

Apparently the default status has changed and now you have to put a bgl.glDepthFunc(bgl.GL_LEQUAL) before :
This change is inconvenient as it can break some addons and GL_LEQUAL is certainly more suitable as the default.
However, it is good to keep in mind that some addon callbacks can change the drawing status without warning.

Perhaps this is another problem to be considered in blender/blender-addons#80730 (BGL deprecation).

Apparently the default status has changed and now you have to put a `bgl.glDepthFunc(bgl.GL_LEQUAL)` before :\ This change is inconvenient as it can break some addons and `GL_LEQUAL` is certainly more suitable as the default. However, it is good to keep in mind that some addon callbacks can change the drawing status without warning. Perhaps this is another problem to be considered in blender/blender-addons#80730 (BGL deprecation).

MACHIN3 commented

2020-11-20 15:56:12 +01:00

Thanks for pointing that out, much appreciated!

Campbell Barton commented

2021-01-28 12:15:49 +01:00

Closed as duplicate of #81334

Campbell Barton closed this issue

2021-01-28 12:15:49 +01:00

Campbell Barton commented

2021-01-28 12:15:58 +01:00

Changed status from 'Duplicate' to: 'Resolved'

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inverted GL_DEPTH_TEST behavior depending on object selection or presence of non-geo object #82843