# Objective allow extending `Material`s (including the built in `StandardMaterial`) with custom vertex/fragment shaders and additional data, to easily get pbr lighting with custom modifications, or otherwise extend a base material. # Solution - added `ExtendedMaterial<B: Material, E: MaterialExtension>` which contains a base material and a user-defined extension. - added example `extended_material` showing how to use it - modified AsBindGroup to have "unprepared" functions that return raw resources / layout entries so that the extended material can combine them note: doesn't currently work with array resources, as i can't figure out how to make the OwnedBindingResource::get_binding() work, as wgpu requires a `&'a[&'a TextureView]` and i have a `Vec<TextureView>`. # Migration Guide manual implementations of `AsBindGroup` will need to be adjusted, the changes are pretty straightforward and can be seen in the diff for e.g. the `texture_binding_array` example. --------- Co-authored-by: Robert Swain <robert.swain@gmail.com>
54 lines
2.0 KiB
WebGPU Shading Language
54 lines
2.0 KiB
WebGPU Shading Language
#import bevy_pbr::pbr_fragment pbr_input_from_standard_material
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#import bevy_pbr::pbr_functions alpha_discard
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#ifdef PREPASS_PIPELINE
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#import bevy_pbr::prepass_io VertexOutput, FragmentOutput
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#import bevy_pbr::pbr_deferred_functions deferred_output
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#else
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#import bevy_pbr::forward_io VertexOutput, FragmentOutput
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#import bevy_pbr::pbr_functions apply_pbr_lighting, main_pass_post_lighting_processing
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#endif
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struct MyExtendedMaterial {
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quantize_steps: u32,
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}
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@group(1) @binding(100)
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var<uniform> my_extended_material: MyExtendedMaterial;
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@fragment
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fn fragment(
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in: VertexOutput,
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@builtin(front_facing) is_front: bool,
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) -> FragmentOutput {
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// generate a PbrInput struct from the StandardMaterial bindings
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var pbr_input = pbr_input_from_standard_material(in, is_front);
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// we can optionally modify the input before lighting and alpha_discard is applied
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pbr_input.material.base_color.b = pbr_input.material.base_color.r;
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// alpha discard
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pbr_input.material.base_color = alpha_discard(pbr_input.material, pbr_input.material.base_color);
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#ifdef PREPASS_PIPELINE
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// in deferred mode we can't modify anything after that, as lighting is run in a separate fullscreen shader.
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let out = deferred_output(in, pbr_input);
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#else
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var out: FragmentOutput;
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// apply lighting
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out.color = apply_pbr_lighting(pbr_input);
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// we can optionally modify the lit color before post-processing is applied
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out.color = vec4<f32>(vec4<u32>(out.color * f32(my_extended_material.quantize_steps))) / f32(my_extended_material.quantize_steps);
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// apply in-shader post processing (fog, alpha-premultiply, and also tonemapping, debanding if the camera is non-hdr)
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// note this does not include fullscreen postprocessing effects like bloom.
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out.color = main_pass_post_lighting_processing(pbr_input, out.color);
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// we can optionally modify the final result here
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out.color = out.color * 2.0;
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#endif
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return out;
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}
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