3D: Strange shadows - Githubissues

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3D: Strange shadows #49601

Open benoitdm-oslandia opened 2 years ago

benoitdm-oslandia commented 2 years ago

What is the bug or the crash?

When displaying shadows with a flat or dtm terrain, a strange big black appears and no shadows are displayed inside.

Here with a dtm: strange_shadow_dtm

Here without a dtm ie. all dtm layers are removed (only building layer remains), using a flat terrain: strange_shadow_wo_dtm

Also when this bug occurs, only a small scene part can have shadows: strange_shadow_partial_triangle

Here is a screencast: strange_shadow

Steps to reproduce the issue

Here is an example project: elevation_building_issue.zip elevation_building_issue_attachments.zip

dtm and building are from the test data folder (tests/testdata/3d/dtm.tif and tests/testdata/3d/buildings.shp).

Versions

Built from master source tree

Supported QGIS version

[ ] I'm running a supported QGIS version according to the roadmap.

New profile

[ ] I tried with a new QGIS profile

Additional context

No response

wonder-sk commented 2 years ago

Yeah in some cases the shadow rendering does not work well. Some of it may be bugs in the implementation, but more generally I think we need a different approach to shadow rendering (there are lots of different algorithms with different tradeoffs)