[TRACKER] LightmapGI (GPU lightmapper) issues

[Calinou]

This is a tracker issue for the GPU-based lightmapper in the master branch. See #55328 for VoxelGI issues, #55327 for SDFGI issues and #66628 for ReflectionProbe issues. See #56080 for issues specific to the CPU-based BakedLightmap in 3.x.

This tracker only tracks issues in the master branch, not 3.x.

Bugs

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1. Vulkan: LightmapProbes only bake indirect light #40181
   archived bug confirmed topic:3d topic:rendering +5
2. Vulkan: LightmapGI's Directional property only works correctly when lights' bake mode is Dynamic, not Static #49936
   bug confirmed topic:3d topic:rendering +4
3. Vulkan: LightmapGI does not take light nodes' indirect energy into account (unlike BakedLightmap in 3.x) #52257
   bug regression topic:3d topic:rendering +4
4. Vulkan: LightmapGI banding visible on baked lighting due to 8 bpc lossless compression being used by default (even with denoising enabled) #53436
   bug topic:3d topic:editor topic:rendering +4
5. Vulkan: Importing 3D scene with Static Lightmaps disables automatic LOD #53818
   bug confirmed performance topic:3d topic:rendering +5
6. Vulkan: Crash when baking lightmaps with LightmapGI if the resulting image is too large (due to CowData using 32-bit ints) #54679
   bug confirmed crash topic:3d topic:editor topic:rendering +6
7. Vulkan Mobile backend: LightmapGI is not sampled during rendering if a DirectionalLight3D with shadows enabled is visible #55867
   bug confirmed topic:3d topic:rendering +4
8. Vulkan Mobile backend: LightmapGI baking does not take environment lighting into account #55868
   bug confirmed topic:3d topic:rendering +4
9. Vulkan: LightmapGI does not take MultiMeshes into account for baking #56027
   bug topic:3d topic:rendering +3
10. Vulkan: LightmapGI does not take GridMap into account for baking #56030
    bug regression topic:3d topic:rendering +4
11. Vulkan: LightmapGI environment lighting samples the sky upside-down #56079
    bug regression topic:3d topic:rendering +4
12. Vulkan: LightmapGI does not take custom sky rotation into account #56135
    bug regression topic:3d topic:rendering +4
13. Vulkan: LightmapGI does not react to non-default environment Color, Energy or Sky Contribution when using the Scene environment mode #56138
    bug topic:3d topic:rendering +3
14. Vulkan: LightmapGI always bakes direct light shadows (for fully baked lights), even for lights that have shadows disabled #56611
    bug discussion topic:3d topic:rendering +4
15. Vulkan: LightmapGI does not obey the GeometryInstance3D Cast Shadow property set to Off #56870
    bug regression topic:3d topic:rendering +4
16. Vulkan: LightmapGI dynamic object lighting does not work (objects are fully black) #57890
    bug confirmed topic:3d topic:rendering +4
17. LightmapGI: Freeze when trying to bake with custom UV2 #63423
    bug confirmed topic:3d topic:rendering +4
18. Vulkan: LightmapGI exhibits light bleeding through occluded areas and face edges #63437
    bug confirmed regression topic:3d topic:rendering +5
19. Vulkan: Directional LightmapGI does not look correct with emissive surface light #64645
    archived bug topic:3d topic:rendering +4
20. Vulkan: Broken colors when baking LightmapGI #65586
    bug confirmed topic:3d topic:rendering +4
    
21. Vulkan: LightmapGI with Environment Mode set to a value other than Disabled exhibits light leaking through one-sided surfaces #69126
    bug topic:3d topic:rendering +3
22. Vulkan: Error when baking LightmapGI if Bounces is set to 0 and there are no lights with Static bake mode #69129
    bug topic:3d topic:editor topic:rendering +4
23. Vulkan: LightmapGI is culled as soon as its origin is outside the camera frustum #71585
    bug topic:3d topic:rendering +3
24. LightmapGI: Some meshes become completely unlit or black when baking lightmaps #73124
    bug confirmed topic:3d topic:rendering +4
25. LightmapGI doesn't take CameraAttributes into account when baking indirect light in lightmaps (and only partially for direct light) #74139
    bug topic:3d topic:rendering +3
26. LightmapGI does not take into account the alpha channel of texture #74947
    archived bug topic:3d topic:rendering +4
27. Vulkan Mobile: Baking lightmaps on Android causes the editor to crash #77001
    bug crash needs testing platform:android topic:rendering topic:thirdparty +6
28. LightmapGI: Dynamic objects don't update immediately after baking lightmaps or (re)loading a scene #77167
    bug confirmed topic:3d topic:rendering +4
29. LightmapGI: Lightmap bake creates probes with invalid bright green/magenta colors #77168
    bug confirmed topic:3d topic:rendering +4
30. LightmapGI: Baking lightmap in medium quality or more generate green invalid probes (low generate black invalid probes) #77169
    bug confirmed topic:3d topic:rendering +4
31. LightmapGI does not take transparency into account when baking shadows. #77590
    bug confirmed topic:3d topic:rendering +4
32. Vulkan: LightmapGI has incorrect indirect light probes when using static directional light #77356
    bug confirmed topic:3d topic:rendering +4
33. Vulkan: Baking LightmapGI incorrectly uses current editor environment #78184
    bug topic:3d topic:editor topic:rendering +4
34. Vulkan: LightmapGI generates completely black output and probes on macOS (Intel driver bug) #80154
    bug platform:macos topic:3d topic:rendering topic:thirdparty +5
35. Lightmap baking crashes if the size required by the mesh is bigger than the size allowed by LightmapGI. #81453
    bug crash topic:3d topic:rendering +4
36. Vulkan: LightmapGI with Directional enabled exhibits negative-colored specular reflections on metallic materials #81556
    bug topic:3d topic:rendering +3
37. Vulkan: Geometric artifacts in LightmapGI texture when baking with Directional enabled #82307
    bug topic:3d topic:rendering +3
38. Vulkan: Baking LightmapGI results in dozens of "Inconsistency found in triangulation while building BSP" messages #82642
    bug confirmed topic:3d topic:rendering +4
39. Vulkan Mobile: LightmapGI rendering exhibits pixelation artifacts on Android #85172
    bug platform:android topic:3d topic:rendering +4
40. SDFGI will only enable if you unassign baked light data from LightmapGI nodes #85702
    bug topic:3d topic:rendering +3
41. Meshes with dynamic GI mode have wrong lighting with lightmaps and Physical Light Units enabled #87568
    bug topic:3d topic:rendering +3
42. Dynamic mesh lighting breaks with Physical Light Units and LightmapGI #88168
    bug topic:3d topic:rendering +3
43. Unshaded debug draw mode still draws lightmaps on meshes #88341
    bug topic:3d topic:rendering +3
44. LightmapGI Directional results in more aliased shadows for lights with Static bake mode #88470
    bug confirmed topic:3d topic:rendering +4
45. LightmapGI does not recognise cull mode in the material #89402
    bug topic:3d topic:rendering +3
46. Lightmap bake fails when trying to bake for the second time to the same path #94214
    bug confirmed topic:3d topic:editor topic:rendering +5
47. Vulkan Mobile: LightmapGI baking makes environment light twice as dark as it should be #94401
    bug topic:3d topic:rendering +3
48. OpenGL: Baking lightmaps has broken emissive material properties #94406
    bug topic:3d topic:rendering +3
49. OpenGL: Condition "t->is_render_target" is true. is printed every time LightmapGI is baked with Environment mode set to Scene or Custom Sky #94407
    bug confirmed topic:3d topic:rendering +4
50. LightMapGI does not correctly apply GI information to inherited GridMap scenes when reopening scenes #95327
    bug topic:3d topic:rendering +3
51. Lightmap bake crash at the beginning of the baking #98180
    bug crash needs testing topic:3d topic:rendering +5
52. Shadow Caster Mask does not affect LightmapGI baking for lights with Static bake mode #98684
    bug discussion topic:3d topic:rendering +4
53. LightmapGI leaks on box PrimitiveMeshes due to poor UV2 generation quality #98685
    bug topic:3d topic:rendering +3

Missing features compared to 3.x's BakedLightmap

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1. Vulkan: LightmapGI bicubic sampling not implemented (unlike BakedLightmap in 3.x) #49935
   confirmed regression topic:3d topic:rendering +4
2. Vulkan: LightmapGI energy not implemented (unlike BakedLightmapData in 3.x) #49968
   enhancement topic:3d topic:rendering +3
3. Vulkan: LightmapGI Environment Min Light property not implemented (unlike BakedLightmap in 3.x) #50568
   enhancement topic:3d topic:rendering +3
4. Vulkan: LightmapGI Use Color property not implemented (unlike BakedLightmap in 3.x) #50569
   enhancement topic:3d topic:rendering +3
5. Vulkan: LightmapGI Use Hdr property not implemented (unlike BakedLightmap in 3.x) #50570
   enhancement topic:3d topic:rendering +3
6. Vulkan: LightmapGI Bounce Indirect Energy property not implemented (unlike BakedLightmap in 3.x) #50938
   enhancement topic:3d topic:rendering +3
7. Vulkan: LightmapGI soft shadows not reimplemented yet (unlike BakedLightmap in 3.x) #52199
   bug topic:3d topic:rendering +3
8. Vulkan: LightmapGI's bake() function is not exposed to scripting (unlike BakedLightmap in 3.x) #59217
   regression topic:3d topic:rendering +3

Enhancements

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1. Vulkan: Importing 3D scene with Static Lightmaps disables automatic LOD #53818
   bug confirmed performance topic:3d topic:rendering +5
2. LightmapGI: Lightmap bounces increase indirect light energy too much #73295
   confirmed discussion topic:3d topic:rendering +4
3. LightmapGI: Lightmap static lights are still counted in real-time light calculations #73289
   archived discussion enhancement performance topic:3d topic:rendering +6
4. Normal maps are not sampled when using lightmap (even if the light still on) #82124
   discussion topic:3d topic:rendering +3
5. Lightmap set to directional bake normal with too little strength #82125
   discussion topic:3d topic:rendering +3
6. Add a property to control emissive material energy in LightmapGI #82839
   enhancement topic:3d topic:rendering +3
7. Implement support for subtractive shadowmapping or shadowmasking in DirectionalLight (for use with BakedLightmap) godot-proposals#2354
   performance topic:3d topic:rendering +3
8. Add debug draw modes to display UV1 and UV2 (lightmap) texel density in the 3D editor godot-proposals#3213
   topic:3d topic:rendering +2
9. Add an editor setting to limit the maximum GPU usage ratio for lightmap baking godot-proposals#3867
   topic:3d topic:editor topic:rendering +3
10. Add a global lightmap texel size multiplier in LightmapGI to speed up preview baking godot-proposals#3893
    topic:3d topic:rendering +2

Pull requests

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1. Add Environment Min Light property to LightmapGI #50572
   enhancement topic:3d topic:rendering +3
2. Add Use Color and Use HDR properties to LightmapGI #50574
   enhancement topic:3d topic:rendering +3
3. Use the Light3D Indirect Energy property in LightmapGI #52256
   archived bug topic:3d topic:rendering +4
4. Add support for soft shadows to the GPU lightmapper #62054
   enhancement topic:3d topic:rendering +3
5. Add a debug draw mode for displaying UV2 (lightmap) texel density #62987
   enhancement salvageable topic:3d topic:rendering +4
6. Make the lightmap size hint property appear as read-only in the editor #77260
   enhancement topic:3d topic:editor topic:rendering +4
7. Reimplement support for bicubic sampling in LightmapGI #77912
   archived enhancement topic:3d topic:rendering +4
8. Add a Preview Bake button for quick iteration with LightmapGI #80518
   enhancement topic:3d topic:editor topic:rendering usability +5
9. Cache lightprobe generation in ligthtmap baking #82915
   enhancement performance topic:3d topic:rendering +4
10. Improve display for lightmap probes in the editor #83863
    enhancement topic:3d topic:editor +3
11. Implement LightmapGI shadowmasks #85653
    enhancement performance topic:3d topic:rendering +4
12. Add Specular Occlusion to meshes under influence of LightmapGI #86102
    enhancement topic:3d topic:rendering +3
13. Implement GI Reflections (SDFGI, VoxelGI) for LightmapGI #86135
    enhancement for pr meeting topic:3d topic:rendering +4
14. Implement bicubic sampling for lightmaps #89919
    enhancement topic:3d topic:rendering +3
15. Add transparency support for LightmapGI #90109
    bug salvageable topic:3d topic:rendering +4
16. LightmapGI: Fix lightleaks caused by insufficient padding and add denoiser range property for LightmapGI #91601
    bug topic:3d topic:rendering +3
17. Add an option to downsample on bake in LightmapGI #93445
    enhancement needs testing topic:3d topic:rendering +4
18. Add Generate LODs, Shadow Mesh and Lightmap UV2 options to OBJ mesh import #94108
    enhancement topic:3d topic:import +3
19. Fix Image CowData crash when baking large lightmaps #94243
    bug topic:core topic:rendering +3
20. Antialias direct light samples in LightmapperRD #95828
    bug topic:3d topic:rendering +3
21. LightmapGI: Clean up and improve lightmap atlas storage #98289
    enhancement topic:3d topic:rendering +3
22. Improve "No meshes to bake" LightmapGI error dialog in the editor #98297
    enhancement topic:3d topic:editor +3