[TRACKER] 4.x OpenGL Compatibility renderer issues

[Calinou]

This issue tracks issues specific to the OpenGL renderer in Godot 4. Godot 3 issues are not tracked here.

See also #55871, which is specific to Vulkan Mobile-only issues.

Bugs

• OpenGL: Directional Shadow Splits debug draw mode is not implemented #46129
• Implement automatic OpenGL fallback for GPUs not supporting Vulkan #58927
• Console errors on the 4.0 Web editor #65702
• OpenGL: GUI rendering issues when hiding nodes #65977
• OpenGL: Environment fog does not affect sky rendering #66456
• OpenGL: Fog color is incorrect if one of the components is exactly 0 #66459
• OpenGL: Fog color is inverted if density is exactly 0 #66462
• OpenGL: Font rendering quality is worse than in Vulkan #66463
• OpenGL: FPS reported by View Frame Time is incorrect due to missing CPU/GPU frame timing information #66464
• NaN diffuse lighting artifacts on lights with very high Attenuation values #68464
• OpenGL: Window stretch mode canvas_items or viewport leaves uncleared section if using keep, keep_width or keep_height stretch aspect #71799
• A 3D material with blend mode "subtract" causes the editor to render completely black in compatibility mode. #72488
• Viewport background transparency not working with environment sky in Compatibility renderer #72602
• OpenGL: Shader render mode blend_mul not working correctly in (and alpha effecting blend modes that shouldn't use alpha) #72873
• OpenGL: GPUParticles2D with Color alpha set to 0 are not transparent #72882
• OpenGL: Point rendering not working #73826
• GridMap renders 3D meshes as solid black with "Compatibility" renderer #74111
• OpenGL: Blend modes other than Mix don't work unless Depth Draw Mode is set to Never #76334
• OpenGL: Godot Editor renders blank interface at launch when using eGPU on macOS #76802
• Anisotropic Filtering not disabled when switching filtering mode in Compatibility renderer #79567
• Project windows jump up after they appear on screen #79581
• Mobile/Compatibility: SpotLight and OmniLight cull masks don't cull moving meshes #82263
• OpenGL: Debug draw modes are not working #82485
• OpenGL: Directional shadow rendering works in the editor, but not in the running project #82503
• OpenGL: DirectionalLight3D applies Fade Start incorrectly when using PSSM 2 Splits or 4 Splits mode #82505
• OpenGL: Clearcoat has no effect if BaseMaterial3D roughness is exactly 0 #83223
• OpenGL: OmniLight3D PCF shadow filtering not implemented #83313
• HDR skybox colors are too dark/bright with compatibility renderer #83788
• Shadows cannot be disabled in the material in the Compatibility renderer #84386
• Physical sky is too dark on compatibility renderer #84441
• VisibleOnScreenNotifier3D does not work with gles3 #87176
• --gpu-index is ineffective when using the Compatibility rendering method #87763
• Proximity Fade broken in Compatibility (OpenGL) #89942
• OpenGL: SpotLight3D shadows occasionally use the wrong texture after moving the camera away from them #92091
• FOG writing in shaders fails with Compatibility renderer unless enabled via WorldEnvironment #94183
• 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
• OpenGL: Selecting a lightmap EXR texture in the FileSystem dock prints an error about SamplerCubeArray not being supported #94408
• Black screen in XR on linux when using compatibility renderer #94455
• On a GPUParticles2D, when using Compatibility renderer, "reverse lifetime" draw order and non-local coords don't play nice. #95042
• Editor freeze when right clicking on second display with Compatibility rendering mode #95873
• When changing screen resolution, having a shader that use 'hint_depth_texture' will cause all shader that use 'hint_screen_texture' to turn black #97728
• Web export renders 1px wide textures completely black. #99399
• OpenGL: Changing Scaling 3D Scale away from 1.0 breaks tonemapping #102860
• Compatibility: Cull Mask on DirectionalLight3D doesn't work #103595
• Compatibility: Tonemapper Exposure Affects Reflection Brightness #104429
• Compatibility: Tonemapper Exposure Affects Lightmapping #104472
• OpenGL: Glowing spots when using LightmapGI [4.4.1 Stable] #106450
• Screen Reading Textures ignore "nearest" filtering flag in compatibility render. #106787
• Glow in Compatibility makes screen texture very dark #107552
• Double-sided shadow casting mode causes MeshInstance3Ds to render without backface culling in the Compatibility renderer #108941

Missing features compared to 3.x GLES3

• OpenGL: Environment glow not implemented yet #66455
• OpenGL: Environment adjustments not implemented yet #66457
• OpenGL: Light3D shadow rendering is not reimplemented yet  #66596
• OpenGL: 2D MSAA antialiasing is not reimplemented yet (3D available since 4.3.dev1) #69462
• OpenGL: FXAA antialiasing is not reimplemented yet #69463
• OpenGL: textureLod() is blocky due to using linear mipmaps instead of Gaussian #72823
• OpenGL: TextureArrays and Texture3D samplers not implemented yet #71029
• OpenGL: ReflectionProbe is not reimplemented yet #86318

Enhancements

• OpenGL: Light3D Shadow Blur property is ignored #82504
• GeometryInstance3D transparency does not work in mobile or compatibility renderers #76774
• Compatibility renderer has lower-quality (ir)radiance map generation than Forward+ and Mobile #95091
• OpenGL: Alpha Hash transparency (and ALPHA_HASH_SCALE in a custom shader) is not implemented yet #103094
• Implement SSAO in the Compatibility rendering method godot-proposals#12059

Pull requests

• Hide volumetric fog, SSIL and SDFGI on Mobile/Compatibility renderers #66465
• Disable creating RD projects in project manager if RD is not supported #91172

[acedogblast]

Missing issue #71799.