[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

• Vulkan: LightmapProbes only bake indirect light #40181
• Vulkan: LightmapGI's Directional property only works correctly when lights' bake mode is Dynamic, not Static #49936
• Vulkan: LightmapGI does not take light nodes' indirect energy into account (unlike BakedLightmap in 3.x) #52257
• Vulkan: LightmapGI banding visible on baked lighting due to 8 bpc lossless compression being used by default (even with denoising enabled) #53436
• Vulkan: Importing 3D scene with Static Lightmaps disables automatic LOD #53818
• Vulkan: Crash when baking lightmaps with LightmapGI if the resulting image is too large (due to CowData using 32-bit ints) #54679
• Vulkan Mobile backend: LightmapGI is not sampled during rendering if a DirectionalLight3D with shadows enabled is visible #55867
• Vulkan Mobile backend: LightmapGI baking does not take environment lighting into account #55868
• Vulkan: LightmapGI does not take MultiMeshes into account for baking #56027
• Vulkan: LightmapGI does not take GridMap into account for baking #56030
• Vulkan: LightmapGI environment lighting samples the sky upside-down #56079
• Vulkan: LightmapGI does not take custom sky rotation into account #56135
• Vulkan: LightmapGI does not react to non-default environment Color, Energy or Sky Contribution when using the Scene environment mode #56138
• Vulkan: LightmapGI always bakes direct light shadows (for fully baked lights), even for lights that have shadows disabled #56611
• Vulkan: LightmapGI does not obey the GeometryInstance3D Cast Shadow property set to Off #56870
• Vulkan: LightmapGI dynamic object lighting does not work (objects are fully black) #57890
• LightmapGI: Freeze when trying to bake with custom UV2 #63423
• Vulkan: LightmapGI exhibits light bleeding through occluded areas and face edges #63437
• Vulkan: Directional LightmapGI does not look correct with emissive surface light #64645
• Vulkan: Broken colors when baking LightmapGI #65586
• Vulkan: LightmapGI with Environment Mode set to a value other than Disabled exhibits light leaking through one-sided surfaces #69126
• Vulkan: Error when baking LightmapGI if Bounces is set to 0 and there are no lights with Static bake mode #69129
• Vulkan: LightmapGI is culled as soon as its origin is outside the camera frustum #71585
• LightmapGI: Some meshes become completely unlit or black when baking lightmaps #73124
• LightmapGI doesn't take CameraAttributes into account when baking indirect light in lightmaps (and only partially for direct light) #74139
• LightmapGI does not take into account the alpha channel of texture #74947
• Vulkan Mobile: Baking lightmaps on Android causes the editor to crash #77001
• LightmapGI: Dynamic objects don't update immediately after baking lightmaps or (re)loading a scene #77167
• LightmapGI: Lightmap bake creates probes with invalid bright green/magenta colors #77168
• LightmapGI: Baking lightmap in medium quality or more generate green invalid probes (low generate black invalid probes) #77169
• LightmapGI does not take transparency into account when baking shadows. #77590
• Vulkan: LightmapGI has incorrect indirect light probes when using static directional light #77356
• Vulkan: Baking LightmapGI incorrectly uses current editor environment #78184
• Vulkan: LightmapGI generates completely black output and probes on macOS (Intel driver bug) #80154
• Lightmap baking crashes if the size required by the mesh is bigger than the size allowed by LightmapGI. #81453
• Vulkan: LightmapGI with Directional enabled exhibits negative-colored specular reflections on metallic materials #81556
• Vulkan: Geometric artifacts in LightmapGI texture when baking with Directional enabled #82307
• Vulkan: Baking LightmapGI results in dozens of "Inconsistency found in triangulation while building BSP" messages #82642
• Vulkan Mobile: LightmapGI rendering exhibits pixelation artifacts on Android #85172
• SDFGI will only enable if you unassign baked light data from LightmapGI nodes #85702
• Meshes with dynamic GI mode have wrong lighting with lightmaps and Physical Light Units enabled #87568
• Dynamic mesh lighting breaks with Physical Light Units and LightmapGI #88168
• Unshaded debug draw mode still draws lightmaps on meshes #88341
• LightmapGI Directional results in more aliased shadows for lights with Static bake mode #88470
• LightmapGI does not recognise cull mode in the material #89402
• Lightmap bake fails when trying to bake for the second time to the same path #94214
• Vulkan Mobile: LightmapGI baking makes environment light twice as dark as it should be #94401
• OpenGL: Baking lightmaps has broken emissive material properties #94406
• 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
• LightMapGI does not correctly apply GI information to inherited GridMap scenes when reopening scenes #95327
• Lightmap bake crash at the beginning of the baking #98180
• Shadow Caster Mask does not affect LightmapGI baking for lights with Static bake mode #98684
• LightmapGI leaks on box PrimitiveMeshes due to poor UV2 generation quality #98685
• LightmapGI: Custom Sky environment does not contribute to ambient light #100591
• Baking a lightmap on a scene that already has a lightmap causes crash #101790
• LightmapGI: Lightmaps with UV2 imported from Blender are broken on 4.4 Beta1 #102164
• LightmapGI appears too saturated with static colored lights since 4.4.beta1 #102203
• LightmapGI makes dynamic objects too bright in indoor scenes, even when Interior is enabled #102949
• Lightmap UV Island Scale Doesn't Match Mesh Scale #104005
• Compatibility: Tonemapper Exposure Affects Lightmapping #104472
• Editor progress dialog's Cancel button does not work on Windows and macOS #104392
• OpenGL: Glowing spots when using LightmapGI [4.4.1 Stable] #106450
• Lightmap bake stall at "Optimizing acceleration structure" for large scenes #106839
• Vulkan Mobile: Lightmaps flicker and unload when there’s more than 2 instances in screen #106906
• Lightmap bake crashes at direct light calculation #106975
• LightmapGI: Light leaks from directional light/environment in closed room #107179
• LightmapGI occasionally displays negative colors on dynamic objects #108526

Missing features compared to 3.x's BakedLightmap

• Vulkan: LightmapGI bicubic sampling not implemented (unlike BakedLightmap in 3.x) #49935
• Vulkan: LightmapGI energy not implemented (unlike BakedLightmapData in 3.x) #49968
• Vulkan: LightmapGI Environment Min Light property not implemented (unlike BakedLightmap in 3.x) #50568
• Vulkan: LightmapGI Use Color property not implemented (unlike BakedLightmap in 3.x) #50569
• Vulkan: LightmapGI Use Hdr property not implemented (unlike BakedLightmap in 3.x) #50570
• Vulkan: LightmapGI Bounce Indirect Energy property not implemented (unlike BakedLightmap in 3.x) #50938
• Vulkan: LightmapGI soft shadows not reimplemented yet (unlike BakedLightmap in 3.x) #52199
• Vulkan: LightmapGI's bake() function is not exposed to scripting (unlike BakedLightmap in 3.x) #59217

Enhancements

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

Pull requests

• Add Environment Min Light property to LightmapGI #50572
• Add Use Color and Use HDR properties to LightmapGI #50574
• Use the Light3D Indirect Energy property in LightmapGI #52256
• Add support for soft shadows to the GPU lightmapper #62054
• Add a debug draw mode for displaying UV2 (lightmap) texel density  #62987
• Make the lightmap size hint property appear as read-only in the editor #77260
• Reimplement support for bicubic sampling in LightmapGI #77912
• Add a Preview Bake button for quick iteration with LightmapGI #80518
• Cache lightprobe generation in ligthtmap baking #82915
• Improve display for lightmap probes in the editor #83863
• Implement LightmapGI shadowmasks #85653
• Add Specular Occlusion to meshes under influence of LightmapGI #86102
• Implement GI Reflections (SDFGI, VoxelGI) for LightmapGI #86135
• Implement bicubic sampling for lightmaps #89919
• Add transparency support for LightmapGI #90109
• LightmapGI: Fix lightleaks caused by insufficient padding and add denoiser range property for LightmapGI #91601
• Add an option to downsample on bake in LightmapGI #93445
• Add Generate LODs, Shadow Mesh and Lightmap UV2 options to OBJ mesh import #94108
• Fix Image CowData crash when baking large lightmaps #94243
• Antialias direct light samples in LightmapperRD #95828
• LightmapGI: Clean up and improve lightmap atlas storage #98289
• Improve "No meshes to bake" LightmapGI error dialog in the editor #98297
• Fix dynamic object light leaking in LightmapGI when Interior is enabled #103023

[jcostello]

@clayjohn consider to set 4.1 for the milestone of the lightmaps fixes as they are really important for realistic lighting and mobile performance

[clayjohn]

@clayjohn consider to set 4.1 for the milestone of the lightmaps fixes as they are really important for realistic lighting and mobile performance

It would be amazing if someone tackled these for 4.1! But I can't promise that someone will, volunteers work on what they are interested in working on. 4.x basically means that anything here can get merged as soon as someone makes a PR. 4.1 means that we will have PRs ready to close this issue by 4.1 which is just not realistic.