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