Baking directional lightmaps raises Too many pixels for Image exception

[jcostello]

Tested versions

Godot Engine v4.5.beta.custom_build.46c495ca2

System information

Ubuntu 24.04 nvidia 2060

Issue description

When baking directional lightmap in MRP with texel density = 10 raises exception below. Same bake without directional bakes just fine even to texel density = 20

  ERROR: Too many pixels for Image. Maximum is 16777216x16777216 = 268435456 pixels.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: core/io/image.cpp:2888 - Condition "dsize == 0" is true.
  ERROR: Image format not supported for saving as EXR. Consider saving as PNG.
  ERROR: Saving EXR failed.
  ERROR: scene/3d/lightmap_gi.cpp:871 - Condition "save_err" is true. Returning: LightmapGI::BAKE_ERROR_CANT_CREATE_IMAGE
  ERROR: scene/3d/lightmap_gi.cpp:1291 - Condition "save_err != BAKE_ERROR_OK" is true. Returning: save_err

Steps to reproduce

Use MRP.

bake directional lightmap at 10 texel density

Minimal reproduction project (MRP)

https://drive.google.com/file/d/1x-mvEmF4oaU53j43FKGmysFu9pcENvSh/view?usp=sharing

[Natehhggh]

doing some testing, I can recreate the error, printing the dimensions at the time of the error I'm getting it's generating an 8192x65536 pixel Image, which is 536,870,912 total pixels, the max pixel limit is half that at 268,435,456.

the error message is a bit misleading still as it prints the max size as 16777216x16777216 which is 281,474,976,710,656, and not max pixel value and it might want to be printed as 16384x16384 instead, which appears to be the max texture size

I tried commenting out the error to see what would happen, which caused a crash with a stack trace, I'm assuming the texture size limitation is the reason

[1] /lib/x86_64-linux-gnu/libc.so.6(+0x45330) [0x73b786845330] (??:0) [2] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x521852c) [0x5ced2277252c] (??:0) [3] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x387340d) [0x5ced20dcd40d] (??:0) [4] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x387baa5) [0x5ced20dd5aa5] (??:0) [5] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x2737ef2) [0x5ced1fc91ef2] (??:0) [6] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x2738c62) [0x5ced1fc92c62] (??:0) [7] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0xc53a86) [0x5ced1e1ada86] (??:0) [8] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x56f3686) [0x5ced22c4d686] (??:0) [9] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x53a7288) [0x5ced22901288] (??:0) [10] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x56fcfc5) [0x5ced22c56fc5] (??:0) [11] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x3310214) [0x5ced2086a214] (??:0) [12] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x3311833) [0x5ced2086b833] (??:0) [13] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x3311d0b) [0x5ced2086bd0b] (??:0) [14] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x327d6a5) [0x5ced207d76a5] (??:0) [15] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x327e493) [0x5ced207d8493] (??:0) [16] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x329b44c) [0x5ced207f544c] (??:0) [17] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x32eedfd) [0x5ced20848dfd] (??:0) [18] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x72cd81) [0x5ced1dc86d81] (??:0) [19] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x74a315) [0x5ced1dca4315] (??:0) [20] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x5338bb0) [0x5ced22892bb0] (??:0) [21] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x533c0ed) [0x5ced228960ed] (??:0) [22] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x746172) [0x5ced1dca0172] (??:0) [23] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x711580) [0x5ced1dc6b580] (??:0) [24] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x6b7448) [0x5ced1dc11448] (??:0) [25] /lib/x86_64-linux-gnu/libc.so.6(+0x2a1ca) [0x73b78682a1ca] (??:0) [26] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x8b) [0x73b78682a28b] (??:0) [27] /home/nate/repos/godot/bin/godot.linuxbsd.editor.x86_64(+0x70f0f5) [0x5ced1dc690f5] (??:0) -- END OF C++ BACKTRACE -- ================================================================

[jcostello]

The limit is because higher dimensions can't be handled correctly I guess. But the issue is that directional lightmaps causes this while regular don't. I wonder if this PR could potentially fix this issue #100790

@BlueCube3310

[Natehhggh]

tried that branch to see, it helps but not enough for directional at 10 texel scale brings it down to 402,653,184 total pixels, unsure if undirectional is better, both main and that branch dont bake for me at 20 like you were able to crashes without output

[BlueCube3310]

LightmapGI has a system in place for situations like this, it's supposed to split the lightmaps into multiple textures. The issue is that it only functions in situations when the atlas' height exceeds 16777216, which happens less often than simply going over the maximal pixel count