473 lines
16 KiB
WebGPU Shading Language
473 lines
16 KiB
WebGPU Shading Language
#define_import_path bevy_pbr::pbr_fragment
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#import bevy_pbr::{
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pbr_functions,
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pbr_functions::SampleBias,
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pbr_bindings,
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pbr_types,
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prepass_utils,
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lighting,
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mesh_bindings::mesh,
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mesh_view_bindings::view,
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parallax_mapping::parallaxed_uv,
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lightmap::lightmap,
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}
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#ifdef SCREEN_SPACE_AMBIENT_OCCLUSION
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#import bevy_pbr::mesh_view_bindings::screen_space_ambient_occlusion_texture
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#import bevy_pbr::gtao_utils::gtao_multibounce
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#endif
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#ifdef MESHLET_MESH_MATERIAL_PASS
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#import bevy_pbr::meshlet_visibility_buffer_resolve::VertexOutput
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#else ifdef PREPASS_PIPELINE
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#import bevy_pbr::prepass_io::VertexOutput
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#else
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#import bevy_pbr::forward_io::VertexOutput
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#endif
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// prepare a basic PbrInput from the vertex stage output, mesh binding and view binding
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fn pbr_input_from_vertex_output(
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in: VertexOutput,
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is_front: bool,
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double_sided: bool,
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) -> pbr_types::PbrInput {
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var pbr_input: pbr_types::PbrInput = pbr_types::pbr_input_new();
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#ifdef MESHLET_MESH_MATERIAL_PASS
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pbr_input.flags = in.mesh_flags;
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#else
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pbr_input.flags = mesh[in.instance_index].flags;
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#endif
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pbr_input.is_orthographic = view.clip_from_view[3].w == 1.0;
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pbr_input.V = pbr_functions::calculate_view(in.world_position, pbr_input.is_orthographic);
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pbr_input.frag_coord = in.position;
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pbr_input.world_position = in.world_position;
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#ifdef VERTEX_COLORS
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pbr_input.material.base_color = in.color;
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#endif
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pbr_input.world_normal = pbr_functions::prepare_world_normal(
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in.world_normal,
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double_sided,
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is_front,
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);
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#ifdef LOAD_PREPASS_NORMALS
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pbr_input.N = prepass_utils::prepass_normal(in.position, 0u);
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#else
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pbr_input.N = normalize(pbr_input.world_normal);
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#endif
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return pbr_input;
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}
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// Prepare a full PbrInput by sampling all textures to resolve
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// the material members
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fn pbr_input_from_standard_material(
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in: VertexOutput,
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is_front: bool,
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) -> pbr_types::PbrInput {
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let double_sided = (pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DOUBLE_SIDED_BIT) != 0u;
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var pbr_input: pbr_types::PbrInput = pbr_input_from_vertex_output(in, is_front, double_sided);
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pbr_input.material.flags = pbr_bindings::material.flags;
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pbr_input.material.base_color *= pbr_bindings::material.base_color;
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pbr_input.material.deferred_lighting_pass_id = pbr_bindings::material.deferred_lighting_pass_id;
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// Neubelt and Pettineo 2013, "Crafting a Next-gen Material Pipeline for The Order: 1886"
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let NdotV = max(dot(pbr_input.N, pbr_input.V), 0.0001);
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// Fill in the sample bias so we can sample from textures.
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var bias: SampleBias;
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#ifdef MESHLET_MESH_MATERIAL_PASS
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bias.ddx_uv = in.ddx_uv;
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bias.ddy_uv = in.ddy_uv;
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#else // MESHLET_MESH_MATERIAL_PASS
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bias.mip_bias = view.mip_bias;
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#endif // MESHLET_MESH_MATERIAL_PASS
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#ifdef VERTEX_UVS
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let uv_transform = pbr_bindings::material.uv_transform;
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#ifdef VERTEX_UVS_A
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var uv = (uv_transform * vec3(in.uv, 1.0)).xy;
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#endif
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#ifdef VERTEX_UVS_B
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var uv_b = (uv_transform * vec3(in.uv_b, 1.0)).xy;
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#else
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var uv_b = uv;
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#endif
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#ifdef VERTEX_TANGENTS
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DEPTH_MAP_BIT) != 0u) {
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let V = pbr_input.V;
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let N = in.world_normal;
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let T = in.world_tangent.xyz;
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let B = in.world_tangent.w * cross(N, T);
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// Transform V from fragment to camera in world space to tangent space.
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let Vt = vec3(dot(V, T), dot(V, B), dot(V, N));
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#ifdef VERTEX_UVS_A
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uv = parallaxed_uv(
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pbr_bindings::material.parallax_depth_scale,
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pbr_bindings::material.max_parallax_layer_count,
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pbr_bindings::material.max_relief_mapping_search_steps,
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uv,
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// Flip the direction of Vt to go toward the surface to make the
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// parallax mapping algorithm easier to understand and reason
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// about.
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-Vt,
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);
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#endif
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#ifdef VERTEX_UVS_B
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uv_b = parallaxed_uv(
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pbr_bindings::material.parallax_depth_scale,
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pbr_bindings::material.max_parallax_layer_count,
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pbr_bindings::material.max_relief_mapping_search_steps,
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uv_b,
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// Flip the direction of Vt to go toward the surface to make the
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// parallax mapping algorithm easier to understand and reason
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// about.
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-Vt,
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);
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#else
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uv_b = uv;
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#endif
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}
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#endif // VERTEX_TANGENTS
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_BASE_COLOR_TEXTURE_BIT) != 0u) {
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pbr_input.material.base_color *= pbr_functions::sample_texture(
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pbr_bindings::base_color_texture,
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pbr_bindings::base_color_sampler,
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#ifdef STANDARD_MATERIAL_BASE_COLOR_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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);
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#ifdef ALPHA_TO_COVERAGE
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// Sharpen alpha edges.
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//
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// https://bgolus.medium.com/anti-aliased-alpha-test-the-esoteric-alpha-to-coverage-8b177335ae4f
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let alpha_mode = pbr_bindings::material.flags &
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pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_RESERVED_BITS;
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if alpha_mode == pbr_types::STANDARD_MATERIAL_FLAGS_ALPHA_MODE_ALPHA_TO_COVERAGE {
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pbr_input.material.base_color.a = (pbr_input.material.base_color.a -
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pbr_bindings::material.alpha_cutoff) /
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max(fwidth(pbr_input.material.base_color.a), 0.0001) + 0.5;
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}
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#endif // ALPHA_TO_COVERAGE
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}
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#endif // VERTEX_UVS
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pbr_input.material.flags = pbr_bindings::material.flags;
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// NOTE: Unlit bit not set means == 0 is true, so the true case is if lit
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_UNLIT_BIT) == 0u) {
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pbr_input.material.reflectance = pbr_bindings::material.reflectance;
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pbr_input.material.ior = pbr_bindings::material.ior;
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pbr_input.material.attenuation_color = pbr_bindings::material.attenuation_color;
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pbr_input.material.attenuation_distance = pbr_bindings::material.attenuation_distance;
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pbr_input.material.alpha_cutoff = pbr_bindings::material.alpha_cutoff;
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// emissive
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var emissive: vec4<f32> = pbr_bindings::material.emissive;
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#ifdef VERTEX_UVS
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_EMISSIVE_TEXTURE_BIT) != 0u) {
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emissive = vec4<f32>(emissive.rgb * pbr_functions::sample_texture(
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pbr_bindings::emissive_texture,
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pbr_bindings::emissive_sampler,
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#ifdef STANDARD_MATERIAL_EMISSIVE_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).rgb, emissive.a);
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}
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#endif
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pbr_input.material.emissive = emissive;
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// metallic and perceptual roughness
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var metallic: f32 = pbr_bindings::material.metallic;
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var perceptual_roughness: f32 = pbr_bindings::material.perceptual_roughness;
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let roughness = lighting::perceptualRoughnessToRoughness(perceptual_roughness);
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#ifdef VERTEX_UVS
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_METALLIC_ROUGHNESS_TEXTURE_BIT) != 0u) {
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let metallic_roughness = pbr_functions::sample_texture(
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pbr_bindings::metallic_roughness_texture,
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pbr_bindings::metallic_roughness_sampler,
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#ifdef STANDARD_MATERIAL_METALLIC_ROUGHNESS_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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);
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// Sampling from GLTF standard channels for now
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metallic *= metallic_roughness.b;
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perceptual_roughness *= metallic_roughness.g;
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}
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#endif
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pbr_input.material.metallic = metallic;
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pbr_input.material.perceptual_roughness = perceptual_roughness;
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// Clearcoat factor
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pbr_input.material.clearcoat = pbr_bindings::material.clearcoat;
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#ifdef VERTEX_UVS
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#ifdef PBR_MULTI_LAYER_MATERIAL_TEXTURES_SUPPORTED
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_CLEARCOAT_TEXTURE_BIT) != 0u) {
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pbr_input.material.clearcoat *= pbr_functions::sample_texture(
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pbr_bindings::clearcoat_texture,
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pbr_bindings::clearcoat_sampler,
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#ifdef STANDARD_MATERIAL_CLEARCOAT_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).r;
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}
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#endif // PBR_MULTI_LAYER_MATERIAL_TEXTURES_SUPPORTED
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#endif // VERTEX_UVS
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// Clearcoat roughness
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pbr_input.material.clearcoat_perceptual_roughness = pbr_bindings::material.clearcoat_perceptual_roughness;
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#ifdef VERTEX_UVS
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#ifdef PBR_MULTI_LAYER_MATERIAL_TEXTURES_SUPPORTED
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_CLEARCOAT_ROUGHNESS_TEXTURE_BIT) != 0u) {
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pbr_input.material.clearcoat_perceptual_roughness *= pbr_functions::sample_texture(
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pbr_bindings::clearcoat_roughness_texture,
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pbr_bindings::clearcoat_roughness_sampler,
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#ifdef STANDARD_MATERIAL_CLEARCOAT_ROUGHNESS_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).g;
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}
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#endif // PBR_MULTI_LAYER_MATERIAL_TEXTURES_SUPPORTED
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#endif // VERTEX_UVS
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var specular_transmission: f32 = pbr_bindings::material.specular_transmission;
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#ifdef VERTEX_UVS
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#ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_SPECULAR_TRANSMISSION_TEXTURE_BIT) != 0u) {
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specular_transmission *= pbr_functions::sample_texture(
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pbr_bindings::specular_transmission_texture,
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pbr_bindings::specular_transmission_sampler,
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#ifdef STANDARD_MATERIAL_SPECULAR_TRANSMISSION_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).r;
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}
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#endif
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#endif
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pbr_input.material.specular_transmission = specular_transmission;
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var thickness: f32 = pbr_bindings::material.thickness;
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#ifdef VERTEX_UVS
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#ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_THICKNESS_TEXTURE_BIT) != 0u) {
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thickness *= pbr_functions::sample_texture(
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pbr_bindings::thickness_texture,
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pbr_bindings::thickness_sampler,
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#ifdef STANDARD_MATERIAL_THICKNESS_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).g;
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}
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#endif
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#endif
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// scale thickness, accounting for non-uniform scaling (e.g. a “squished” mesh)
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// TODO: Meshlet support
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#ifndef MESHLET_MESH_MATERIAL_PASS
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thickness *= length(
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(transpose(mesh[in.instance_index].world_from_local) * vec4(pbr_input.N, 0.0)).xyz
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);
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#endif
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pbr_input.material.thickness = thickness;
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var diffuse_transmission = pbr_bindings::material.diffuse_transmission;
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#ifdef VERTEX_UVS
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#ifdef PBR_TRANSMISSION_TEXTURES_SUPPORTED
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_DIFFUSE_TRANSMISSION_TEXTURE_BIT) != 0u) {
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diffuse_transmission *= pbr_functions::sample_texture(
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pbr_bindings::diffuse_transmission_texture,
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pbr_bindings::diffuse_transmission_sampler,
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#ifdef STANDARD_MATERIAL_DIFFUSE_TRANSMISSION_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).a;
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}
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#endif
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#endif
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pbr_input.material.diffuse_transmission = diffuse_transmission;
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var diffuse_occlusion: vec3<f32> = vec3(1.0);
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var specular_occlusion: f32 = 1.0;
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#ifdef VERTEX_UVS
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_OCCLUSION_TEXTURE_BIT) != 0u) {
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diffuse_occlusion *= pbr_functions::sample_texture(
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pbr_bindings::occlusion_texture,
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pbr_bindings::occlusion_sampler,
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#ifdef STANDARD_MATERIAL_OCCLUSION_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).r;
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}
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#endif
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#ifdef SCREEN_SPACE_AMBIENT_OCCLUSION
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let ssao = textureLoad(screen_space_ambient_occlusion_texture, vec2<i32>(in.position.xy), 0i).r;
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let ssao_multibounce = gtao_multibounce(ssao, pbr_input.material.base_color.rgb);
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diffuse_occlusion = min(diffuse_occlusion, ssao_multibounce);
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// Use SSAO to estimate the specular occlusion.
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// Lagarde and Rousiers 2014, "Moving Frostbite to Physically Based Rendering"
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specular_occlusion = saturate(pow(NdotV + ssao, exp2(-16.0 * roughness - 1.0)) - 1.0 + ssao);
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#endif
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pbr_input.diffuse_occlusion = diffuse_occlusion;
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pbr_input.specular_occlusion = specular_occlusion;
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// N (normal vector)
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#ifndef LOAD_PREPASS_NORMALS
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pbr_input.N = normalize(pbr_input.world_normal);
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pbr_input.clearcoat_N = pbr_input.N;
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#ifdef VERTEX_UVS
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#ifdef VERTEX_TANGENTS
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let TBN = pbr_functions::calculate_tbn_mikktspace(pbr_input.world_normal, in.world_tangent);
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#ifdef STANDARD_MATERIAL_NORMAL_MAP
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let Nt = pbr_functions::sample_texture(
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pbr_bindings::normal_map_texture,
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pbr_bindings::normal_map_sampler,
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#ifdef STANDARD_MATERIAL_NORMAL_MAP_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).rgb;
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pbr_input.N = pbr_functions::apply_normal_mapping(
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pbr_bindings::material.flags,
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TBN,
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double_sided,
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is_front,
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Nt,
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);
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#endif // STANDARD_MATERIAL_NORMAL_MAP
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#ifdef STANDARD_MATERIAL_CLEARCOAT
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// Note: `KHR_materials_clearcoat` specifies that, if there's no
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// clearcoat normal map, we must set the normal to the mesh's normal,
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// and not to the main layer's bumped normal.
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#ifdef STANDARD_MATERIAL_CLEARCOAT_NORMAL_MAP
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let clearcoat_Nt = pbr_functions::sample_texture(
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pbr_bindings::clearcoat_normal_texture,
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pbr_bindings::clearcoat_normal_sampler,
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#ifdef STANDARD_MATERIAL_CLEARCOAT_NORMAL_UV_B
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uv_b,
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#else
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uv,
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#endif
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bias,
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).rgb;
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pbr_input.clearcoat_N = pbr_functions::apply_normal_mapping(
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pbr_bindings::material.flags,
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TBN,
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double_sided,
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is_front,
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clearcoat_Nt,
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);
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#endif // STANDARD_MATERIAL_CLEARCOAT_NORMAL_MAP
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#endif // STANDARD_MATERIAL_CLEARCOAT
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#endif // VERTEX_TANGENTS
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#endif // VERTEX_UVS
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// Take anisotropy into account.
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//
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// This code comes from the `KHR_materials_anisotropy` spec:
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// <https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md#individual-lights>
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#ifdef VERTEX_TANGENTS
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#ifdef STANDARD_MATERIAL_ANISOTROPY
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var anisotropy_strength = pbr_bindings::material.anisotropy_strength;
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var anisotropy_direction = pbr_bindings::material.anisotropy_rotation;
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// Adjust based on the anisotropy map if there is one.
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if ((pbr_bindings::material.flags & pbr_types::STANDARD_MATERIAL_FLAGS_ANISOTROPY_TEXTURE_BIT) != 0u) {
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let anisotropy_texel = pbr_functions::sample_texture(
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pbr_bindings::anisotropy_texture,
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pbr_bindings::anisotropy_sampler,
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#ifdef STANDARD_MATERIAL_ANISOTROPY_UV_B
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uv_b,
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#else // STANDARD_MATERIAL_ANISOTROPY_UV_B
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uv,
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#endif // STANDARD_MATERIAL_ANISOTROPY_UV_B
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bias,
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).rgb;
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let anisotropy_direction_from_texture = normalize(anisotropy_texel.rg * 2.0 - 1.0);
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// Rotate by the anisotropy direction.
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anisotropy_direction =
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mat2x2(anisotropy_direction.xy, anisotropy_direction.yx * vec2(-1.0, 1.0)) *
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anisotropy_direction_from_texture;
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|
anisotropy_strength *= anisotropy_texel.b;
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}
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|
|
|
pbr_input.anisotropy_strength = anisotropy_strength;
|
|
|
|
let anisotropy_T = normalize(TBN * vec3(anisotropy_direction, 0.0));
|
|
let anisotropy_B = normalize(cross(pbr_input.world_normal, anisotropy_T));
|
|
pbr_input.anisotropy_T = anisotropy_T;
|
|
pbr_input.anisotropy_B = anisotropy_B;
|
|
|
|
#endif // STANDARD_MATERIAL_ANISOTROPY
|
|
#endif // VERTEX_TANGENTS
|
|
|
|
#endif // LOAD_PREPASS_NORMALS
|
|
|
|
// TODO: Meshlet support
|
|
#ifdef LIGHTMAP
|
|
pbr_input.lightmap_light = lightmap(
|
|
in.uv_b,
|
|
pbr_bindings::material.lightmap_exposure,
|
|
in.instance_index);
|
|
#endif
|
|
}
|
|
|
|
return pbr_input;
|
|
}
|