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https://github.com/bevyengine/bevy
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dd14f3a477
 # Objective Lightmaps, textures that store baked global illumination, have been a mainstay of real-time graphics for decades. Bevy currently has no support for them, so this pull request implements them. ## Solution The new `Lightmap` component can be attached to any entity that contains a `Handle<Mesh>` and a `StandardMaterial`. When present, it will be applied in the PBR shader. Because multiple lightmaps are frequently packed into atlases, each lightmap may have its own UV boundaries within its texture. An `exposure` field is also provided, to control the brightness of the lightmap. Note that this PR doesn't provide any way to bake the lightmaps. That can be done with [The Lightmapper] or another solution, such as Unity's Bakery. --- ## Changelog ### Added * A new component, `Lightmap`, is available, for baked global illumination. If your mesh has a second UV channel (UV1), and you attach this component to the entity with that mesh, Bevy will apply the texture referenced in the lightmap. [The Lightmapper]: https://github.com/Naxela/The_Lightmapper --------- Co-authored-by: Carter Anderson <mcanders1@gmail.com>
29 lines
1 KiB
WebGPU Shading Language
29 lines
1 KiB
WebGPU Shading Language
#define_import_path bevy_pbr::lightmap
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#import bevy_pbr::mesh_bindings::mesh
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@group(1) @binding(4) var lightmaps_texture: texture_2d<f32>;
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@group(1) @binding(5) var lightmaps_sampler: sampler;
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// Samples the lightmap, if any, and returns indirect illumination from it.
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fn lightmap(uv: vec2<f32>, exposure: f32, instance_index: u32) -> vec3<f32> {
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let packed_uv_rect = mesh[instance_index].lightmap_uv_rect;
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let uv_rect = vec4<f32>(vec4<u32>(
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packed_uv_rect.x & 0xffffu,
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packed_uv_rect.x >> 16u,
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packed_uv_rect.y & 0xffffu,
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packed_uv_rect.y >> 16u)) / 65535.0;
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let lightmap_uv = mix(uv_rect.xy, uv_rect.zw, uv);
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// Mipmapping lightmaps is usually a bad idea due to leaking across UV
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// islands, so there's no harm in using mip level 0 and it lets us avoid
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// control flow uniformity problems.
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//
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// TODO(pcwalton): Consider bicubic filtering.
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return textureSampleLevel(
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lightmaps_texture,
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lightmaps_sampler,
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lightmap_uv,
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0.0).rgb * exposure;
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}
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