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(Before)  (After)   # Objective - Improve lighting; especially reflections. - Closes https://github.com/bevyengine/bevy/issues/4581. ## Solution - Implement environment maps, providing better ambient light. - Add microfacet multibounce approximation for specular highlights from Filament. - Occlusion is no longer incorrectly applied to direct lighting. It now only applies to diffuse indirect light. Unsure if it's also supposed to apply to specular indirect light - the glTF specification just says "indirect light". In the case of ambient occlusion, for instance, that's usually only calculated as diffuse though. For now, I'm choosing to apply this just to indirect diffuse light, and not specular. - Modified the PBR example to use an environment map, and have labels. - Added `FallbackImageCubemap`. ## Implementation - IBL technique references can be found in environment_map.wgsl. - It's more accurate to use a LUT for the scale/bias. Filament has a good reference on generating this LUT. For now, I just used an analytic approximation. - For now, environment maps must first be prefiltered outside of bevy using a 3rd party tool. See the `EnvironmentMap` documentation. - Eventually, we should have our own prefiltering code, so that we can have dynamically changing environment maps, as well as let users drop in an HDR image and use asset preprocessing to create the needed textures using only bevy. --- ## Changelog - Added an `EnvironmentMapLight` camera component that adds additional ambient light to a scene. - StandardMaterials will now appear brighter and more saturated at high roughness, due to internal material changes. This is more physically correct. - Fixed StandardMaterial occlusion being incorrectly applied to direct lighting. - Added `FallbackImageCubemap`. Co-authored-by: IceSentry <c.giguere42@gmail.com> Co-authored-by: James Liu <contact@jamessliu.com> Co-authored-by: Rob Parrett <robparrett@gmail.com>
6 lines
750 B
Text
6 lines
750 B
Text
The pisa_*.ktx2 files were generated from https://github.com/KhronosGroup/glTF-Sample-Environments/blob/master/pisa.hdr using the following tools and commands:
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- IBL environment map prefiltering to cubemaps: https://github.com/KhronosGroup/glTF-IBL-Sampler
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- Diffuse: ./cli -inputPath pisa.hdr -outCubeMap pisa_diffuse.ktx2 -distribution Lambertian -cubeMapResolution 32
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- Specular: ./cli -inputPath pisa.hdr -outCubeMap pisa_specular.ktx2 -distribution GGX -cubeMapResolution 512
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- Converting to rgb9e5 format with zstd 'supercompression': https://github.com/DGriffin91/bevy_mod_environment_map_tools
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- cargo run --release -- --inputs pisa_diffuse.ktx2,pisa_specular.ktx2 --outputs pisa_diffuse_rgb9e5_zstd.ktx2,pisa_specular_rgb9e5_zstd.ktx2
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