[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
• LightmapGI Cancel Button Does Not Work #104392

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