increase max num of lights

src/main.rs

@@ -1,5 +1,7 @@
 use bevy::{input::system::exit_on_esc_system, pbr::AmbientLight, prelude::*};
 
+mod rendering;
+
 mod light_balls;
 use light_balls::*;
 mod player;
@@ -10,7 +12,7 @@ use columns::*;
 fn main() {
     App::build()
         .insert_resource(Msaa { samples: 4 })
-        .add_plugins(DefaultPlugins)
+        .add_plugins(rendering::CustomPlugins)
         .init_resource::<LightBallMaterials>()
         .add_startup_system(setup.system())
         .add_system(exit_on_esc_system.system())

src/player.rs

@@ -31,7 +31,7 @@ pub fn spawn_player(
             light_material.emissive = Color::rgb(15.0, 15.0, 15.0);
             let light_material = materials.add(light_material);
 
-            for i in 0..5 {
+            for i in 0..10 {
                 parent
                     .spawn_bundle(PbrBundle {
                         mesh: meshes.add(Mesh::from(shape::Icosphere {

src/rendering/mod.rs

@@ -0,0 +1,102 @@
+use bevy::app::{PluginGroup, PluginGroupBuilder};
+use bevy::pbr::render_graph::{LightsNode, PBR_PIPELINE_HANDLE};
+use bevy::prelude::*;
+use bevy::render::{
+    pipeline::PipelineDescriptor,
+    render_graph::{base, AssetRenderResourcesNode, RenderGraph, RenderResourcesNode},
+    shader::Shader,
+};
+
+mod pipeline;
+use pipeline::build_pbr_pipeline;
+
+pub struct CustomPlugins;
+impl PluginGroup for CustomPlugins {
+    fn build(&mut self, group: &mut PluginGroupBuilder) {
+        group.add(bevy::log::LogPlugin::default());
+        group.add(bevy::core::CorePlugin::default());
+        group.add(bevy::transform::TransformPlugin::default());
+        group.add(bevy::diagnostic::DiagnosticsPlugin::default());
+        group.add(bevy::input::InputPlugin::default());
+        group.add(bevy::window::WindowPlugin::default());
+        group.add(bevy::asset::AssetPlugin::default());
+        group.add(bevy::scene::ScenePlugin::default());
+
+        group.add(bevy::render::RenderPlugin::default());
+        group.add(bevy::sprite::SpritePlugin::default());
+        group.add(CustomPbrPlugin::default());
+        group.add(bevy::ui::UiPlugin::default());
+        group.add(bevy::text::TextPlugin::default());
+        group.add(bevy::gilrs::GilrsPlugin::default());
+        group.add(bevy::gltf::GltfPlugin::default());
+        group.add(bevy::winit::WinitPlugin::default());
+        group.add(bevy::wgpu::WgpuPlugin::default());
+    }
+}
+
+#[derive(Default)]
+pub struct CustomPbrPlugin;
+impl Plugin for CustomPbrPlugin {
+    fn build(&self, app: &mut AppBuilder) {
+        app.add_asset::<StandardMaterial>()
+            .register_type::<Light>()
+            .add_system_to_stage(
+                CoreStage::PostUpdate,
+                bevy::render::shader::asset_shader_defs_system::<StandardMaterial>.system(),
+            )
+            .init_resource::<bevy::pbr::AmbientLight>();
+        add_pbr_graph(app.world_mut());
+
+        // add default StandardMaterial
+        let mut materials = app
+            .world_mut()
+            .get_resource_mut::<Assets<StandardMaterial>>()
+            .unwrap();
+        materials.set_untracked(
+            Handle::<StandardMaterial>::default(),
+            StandardMaterial {
+                base_color: Color::PINK,
+                unlit: true,
+                ..Default::default()
+            },
+        );
+    }
+}
+
+/// the names of pbr graph nodes
+mod node {
+    pub const TRANSFORM: &str = "transform";
+    pub const STANDARD_MATERIAL: &str = "standard_material";
+    pub const LIGHTS: &str = "lights";
+}
+
+fn add_pbr_graph(world: &mut World) {
+    {
+        let mut graph = world.get_resource_mut::<RenderGraph>().unwrap();
+        graph.add_system_node(
+            node::TRANSFORM,
+            RenderResourcesNode::<GlobalTransform>::new(true),
+        );
+        graph.add_system_node(
+            node::STANDARD_MATERIAL,
+            AssetRenderResourcesNode::<StandardMaterial>::new(true),
+        );
+        graph.add_system_node(node::LIGHTS, LightsNode::new(30));
+
+        // TODO: replace these with "autowire" groups
+        graph
+            .add_node_edge(node::STANDARD_MATERIAL, base::node::MAIN_PASS)
+            .unwrap();
+        graph
+            .add_node_edge(node::TRANSFORM, base::node::MAIN_PASS)
+            .unwrap();
+        graph
+            .add_node_edge(node::LIGHTS, base::node::MAIN_PASS)
+            .unwrap();
+    }
+    let pipeline = build_pbr_pipeline(&mut world.get_resource_mut::<Assets<Shader>>().unwrap());
+    let mut pipelines = world
+        .get_resource_mut::<Assets<PipelineDescriptor>>()
+        .unwrap();
+    pipelines.set_untracked(PBR_PIPELINE_HANDLE, pipeline);
+}

src/rendering/pbr.frag

@@ -0,0 +1,392 @@
+// From the Filament design doc
+// https://google.github.io/filament/Filament.html#table_symbols
+// Symbol Definition
+// v    View unit vector
+// l    Incident light unit vector
+// n    Surface normal unit vector
+// h    Half unit vector between l and v
+// f    BRDF
+// f_d    Diffuse component of a BRDF
+// f_r    Specular component of a BRDF
+// α    Roughness, remapped from using input perceptualRoughness
+// σ    Diffuse reflectance
+// Ω    Spherical domain
+// f0    Reflectance at normal incidence
+// f90    Reflectance at grazing angle
+// χ+(a)    Heaviside function (1 if a>0 and 0 otherwise)
+// nior    Index of refraction (IOR) of an interface
+// ⟨n⋅l⟩    Dot product clamped to [0..1]
+// ⟨a⟩    Saturated value (clamped to [0..1])
+
+// The Bidirectional Reflectance Distribution Function (BRDF) describes the surface response of a standard material
+// and consists of two components, the diffuse component (f_d) and the specular component (f_r):
+// f(v,l) = f_d(v,l) + f_r(v,l)
+//
+// The form of the microfacet model is the same for diffuse and specular
+// f_r(v,l) = f_d(v,l) = 1 / { |n⋅v||n⋅l| } ∫_Ω D(m,α) G(v,l,m) f_m(v,l,m) (v⋅m) (l⋅m) dm
+//
+// In which:
+// D, also called the Normal Distribution Function (NDF) models the distribution of the microfacets
+// G models the visibility (or occlusion or shadow-masking) of the microfacets
+// f_m is the microfacet BRDF and differs between specular and diffuse components
+//
+// The above integration needs to be approximated.
+
+#version 450
+
+const int MAX_LIGHTS = 10;
+
+struct Light {
+    mat4 proj;
+    vec4 pos;
+    vec4 color;
+};
+
+layout(location = 0) in vec3 v_WorldPosition;
+layout(location = 1) in vec3 v_WorldNormal;
+layout(location = 2) in vec2 v_Uv;
+
+#ifdef STANDARDMATERIAL_NORMAL_MAP
+layout(location = 3) in vec4 v_WorldTangent;
+#endif
+
+layout(location = 0) out vec4 o_Target;
+
+layout(set = 0, binding = 0) uniform CameraViewProj {
+    mat4 ViewProj;
+};
+layout(std140, set = 0, binding = 1) uniform CameraPosition {
+    vec4 CameraPos;
+};
+
+layout(std140, set = 1, binding = 0) uniform Lights {
+    vec4 AmbientColor;
+    uvec4 NumLights;
+    Light SceneLights[MAX_LIGHTS];
+};
+
+layout(set = 3, binding = 0) uniform StandardMaterial_base_color {
+    vec4 base_color;
+};
+
+#ifdef STANDARDMATERIAL_BASE_COLOR_TEXTURE
+layout(set = 3, binding = 1) uniform texture2D StandardMaterial_base_color_texture;
+layout(set = 3,
+       binding = 2) uniform sampler StandardMaterial_base_color_texture_sampler;
+#endif
+
+#ifndef STANDARDMATERIAL_UNLIT
+
+layout(set = 3, binding = 3) uniform StandardMaterial_roughness {
+    float perceptual_roughness;
+};
+
+layout(set = 3, binding = 4) uniform StandardMaterial_metallic {
+    float metallic;
+};
+
+#    ifdef STANDARDMATERIAL_METALLIC_ROUGHNESS_TEXTURE
+layout(set = 3, binding = 5) uniform texture2D StandardMaterial_metallic_roughness_texture;
+layout(set = 3,
+       binding = 6) uniform sampler StandardMaterial_metallic_roughness_texture_sampler;
+#    endif
+
+layout(set = 3, binding = 7) uniform StandardMaterial_reflectance {
+    float reflectance;
+};
+
+#    ifdef STANDARDMATERIAL_NORMAL_MAP
+layout(set = 3, binding = 8) uniform texture2D StandardMaterial_normal_map;
+layout(set = 3,
+       binding = 9) uniform sampler StandardMaterial_normal_map_sampler;
+#    endif
+
+#    if defined(STANDARDMATERIAL_OCCLUSION_TEXTURE)
+layout(set = 3, binding = 10) uniform texture2D StandardMaterial_occlusion_texture;
+layout(set = 3,
+       binding = 11) uniform sampler StandardMaterial_occlusion_texture_sampler;
+#    endif
+
+layout(set = 3, binding = 12) uniform StandardMaterial_emissive {
+    vec4 emissive;
+};
+
+#    if defined(STANDARDMATERIAL_EMISSIVE_TEXTURE)
+layout(set = 3, binding = 13) uniform texture2D StandardMaterial_emissive_texture;
+layout(set = 3,
+       binding = 14) uniform sampler StandardMaterial_emissive_texture_sampler;
+#    endif
+
+#    define saturate(x) clamp(x, 0.0, 1.0)
+const float PI = 3.141592653589793;
+
+float pow5(float x) {
+    float x2 = x * x;
+    return x2 * x2 * x;
+}
+
+// distanceAttenuation is simply the square falloff of light intensity
+// combined with a smooth attenuation at the edge of the light radius
+//
+// light radius is a non-physical construct for efficiency purposes,
+// because otherwise every light affects every fragment in the scene
+float getDistanceAttenuation(const vec3 posToLight, float inverseRadiusSquared) {
+    float distanceSquare = dot(posToLight, posToLight);
+    float factor = distanceSquare * inverseRadiusSquared;
+    float smoothFactor = saturate(1.0 - factor * factor);
+    float attenuation = smoothFactor * smoothFactor;
+    return attenuation * 1.0 / max(distanceSquare, 1e-4);
+}
+
+// Normal distribution function (specular D)
+// Based on https://google.github.io/filament/Filament.html#citation-walter07
+
+// D_GGX(h,α) = α^2 / { π ((n⋅h)^2 (α2−1) + 1)^2 }
+
+// Simple implementation, has precision problems when using fp16 instead of fp32
+// see https://google.github.io/filament/Filament.html#listing_speculardfp16
+float D_GGX(float roughness, float NoH, const vec3 h) {
+    float oneMinusNoHSquared = 1.0 - NoH * NoH;
+    float a = NoH * roughness;
+    float k = roughness / (oneMinusNoHSquared + a * a);
+    float d = k * k * (1.0 / PI);
+    return d;
+}
+
+// Visibility function (Specular G)
+// V(v,l,a) = G(v,l,α) / { 4 (n⋅v) (n⋅l) }
+// such that f_r becomes
+// f_r(v,l) = D(h,α) V(v,l,α) F(v,h,f0)
+// where
+// V(v,l,α) = 0.5 / { n⋅l sqrt((n⋅v)^2 (1−α2) + α2) + n⋅v sqrt((n⋅l)^2 (1−α2) + α2) }
+// Note the two sqrt's, that may be slow on mobile, see https://google.github.io/filament/Filament.html#listing_approximatedspecularv
+float V_SmithGGXCorrelated(float roughness, float NoV, float NoL) {
+    float a2 = roughness * roughness;
+    float lambdaV = NoL * sqrt((NoV - a2 * NoV) * NoV + a2);
+    float lambdaL = NoV * sqrt((NoL - a2 * NoL) * NoL + a2);
+    float v = 0.5 / (lambdaV + lambdaL);
+    return v;
+}
+
+// Fresnel function
+// see https://google.github.io/filament/Filament.html#citation-schlick94
+// F_Schlick(v,h,f_0,f_90) = f_0 + (f_90 − f_0) (1 − v⋅h)^5
+vec3 F_Schlick(const vec3 f0, float f90, float VoH) {
+    // not using mix to keep the vec3 and float versions identical
+    return f0 + (f90 - f0) * pow5(1.0 - VoH);
+}
+
+float F_Schlick(float f0, float f90, float VoH) {
+    // not using mix to keep the vec3 and float versions identical
+    return f0 + (f90 - f0) * pow5(1.0 - VoH);
+}
+
+vec3 fresnel(vec3 f0, float LoH) {
+    // f_90 suitable for ambient occlusion
+    // see https://google.github.io/filament/Filament.html#lighting/occlusion
+    float f90 = saturate(dot(f0, vec3(50.0 * 0.33)));
+    return F_Schlick(f0, f90, LoH);
+}
+
+// Specular BRDF
+// https://google.github.io/filament/Filament.html#materialsystem/specularbrdf
+
+// Cook-Torrance approximation of the microfacet model integration using Fresnel law F to model f_m
+// f_r(v,l) = { D(h,α) G(v,l,α) F(v,h,f0) } / { 4 (n⋅v) (n⋅l) }
+vec3 specular(vec3 f0, float roughness, const vec3 h, float NoV, float NoL,
+              float NoH, float LoH) {
+    float D = D_GGX(roughness, NoH, h);
+    float V = V_SmithGGXCorrelated(roughness, NoV, NoL);
+    vec3 F = fresnel(f0, LoH);
+
+    return (D * V) * F;
+}
+
+// Diffuse BRDF
+// https://google.github.io/filament/Filament.html#materialsystem/diffusebrdf
+// fd(v,l) = σ/π * 1 / { |n⋅v||n⋅l| } ∫Ω D(m,α) G(v,l,m) (v⋅m) (l⋅m) dm
+
+// simplest approximation
+// float Fd_Lambert() {
+//     return 1.0 / PI;
+// }
+//
+// vec3 Fd = diffuseColor * Fd_Lambert();
+
+// Disney approximation
+// See https://google.github.io/filament/Filament.html#citation-burley12
+// minimal quality difference
+float Fd_Burley(float roughness, float NoV, float NoL, float LoH) {
+    float f90 = 0.5 + 2.0 * roughness * LoH * LoH;
+    float lightScatter = F_Schlick(1.0, f90, NoL);
+    float viewScatter = F_Schlick(1.0, f90, NoV);
+    return lightScatter * viewScatter * (1.0 / PI);
+}
+
+// From https://www.unrealengine.com/en-US/blog/physically-based-shading-on-mobile
+vec3 EnvBRDFApprox(vec3 f0, float perceptual_roughness, float NoV) {
+    const vec4 c0 = { -1, -0.0275, -0.572, 0.022 };
+    const vec4 c1 = { 1, 0.0425, 1.04, -0.04 };
+    vec4 r = perceptual_roughness * c0 + c1;
+    float a004 = min(r.x * r.x, exp2(-9.28 * NoV)) * r.x + r.y;
+    vec2 AB = vec2(-1.04, 1.04) * a004 + r.zw;
+    return f0 * AB.x + AB.y;
+}
+
+float perceptualRoughnessToRoughness(float perceptualRoughness) {
+    // clamp perceptual roughness to prevent precision problems
+    // According to Filament design 0.089 is recommended for mobile
+    // Filament uses 0.045 for non-mobile
+    float clampedPerceptualRoughness = clamp(perceptualRoughness, 0.089, 1.0);
+    return clampedPerceptualRoughness * clampedPerceptualRoughness;
+}
+
+// from https://64.github.io/tonemapping/
+// reinhard on RGB oversaturates colors
+vec3 reinhard(vec3 color) {
+    return color / (1.0 + color);
+}
+
+vec3 reinhard_extended(vec3 color, float max_white) {
+    vec3 numerator = color * (1.0f + (color / vec3(max_white * max_white)));
+    return numerator / (1.0 + color);
+}
+
+// luminance coefficients from Rec. 709.
+// https://en.wikipedia.org/wiki/Rec._709
+float luminance(vec3 v) {
+    return dot(v, vec3(0.2126, 0.7152, 0.0722));
+}
+
+vec3 change_luminance(vec3 c_in, float l_out) {
+    float l_in = luminance(c_in);
+    return c_in * (l_out / l_in);
+}
+
+vec3 reinhard_luminance(vec3 color) {
+    float l_old = luminance(color);
+    float l_new = l_old / (1.0f + l_old);
+    return change_luminance(color, l_new);
+}
+
+vec3 reinhard_extended_luminance(vec3 color, float max_white_l) {
+    float l_old = luminance(color);
+    float numerator = l_old * (1.0f + (l_old / (max_white_l * max_white_l)));
+    float l_new = numerator / (1.0f + l_old);
+    return change_luminance(color, l_new);
+}
+
+#endif
+
+void main() {
+    vec4 output_color = base_color;
+#ifdef STANDARDMATERIAL_BASE_COLOR_TEXTURE
+    output_color *= texture(sampler2D(StandardMaterial_base_color_texture,
+                                      StandardMaterial_base_color_texture_sampler),
+                            v_Uv);
+#endif
+
+#ifndef STANDARDMATERIAL_UNLIT
+    // calculate non-linear roughness from linear perceptualRoughness
+#    ifdef STANDARDMATERIAL_METALLIC_ROUGHNESS_TEXTURE
+    vec4 metallic_roughness = texture(sampler2D(StandardMaterial_metallic_roughness_texture, StandardMaterial_metallic_roughness_texture_sampler), v_Uv);
+    // Sampling from GLTF standard channels for now
+    float metallic = metallic * metallic_roughness.b;
+    float perceptual_roughness = perceptual_roughness * metallic_roughness.g;
+#    endif
+
+    float roughness = perceptualRoughnessToRoughness(perceptual_roughness);
+
+    vec3 N = normalize(v_WorldNormal);
+
+#    ifdef STANDARDMATERIAL_NORMAL_MAP
+    vec3 T = normalize(v_WorldTangent.xyz);
+    vec3 B = cross(N, T) * v_WorldTangent.w;
+#    endif
+
+#    ifdef STANDARDMATERIAL_DOUBLE_SIDED
+    N = gl_FrontFacing ? N : -N;
+#        ifdef STANDARDMATERIAL_NORMAL_MAP
+    T = gl_FrontFacing ? T : -T;
+    B = gl_FrontFacing ? B : -B;
+#        endif
+#    endif
+
+#    ifdef STANDARDMATERIAL_NORMAL_MAP
+    mat3 TBN = mat3(T, B, N);
+    N = TBN * normalize(texture(sampler2D(StandardMaterial_normal_map, StandardMaterial_normal_map_sampler), v_Uv).rgb * 2.0 - 1.0);
+#    endif
+
+#    ifdef STANDARDMATERIAL_OCCLUSION_TEXTURE
+    float occlusion = texture(sampler2D(StandardMaterial_occlusion_texture, StandardMaterial_occlusion_texture_sampler), v_Uv).r;
+#    else
+    float occlusion = 1.0;
+#    endif
+
+#    ifdef STANDARDMATERIAL_EMISSIVE_TEXTURE
+    vec4 emissive = emissive;
+    // TODO use .a for exposure compensation in HDR
+    emissive.rgb *= texture(sampler2D(StandardMaterial_emissive_texture, StandardMaterial_emissive_texture_sampler), v_Uv).rgb;
+#    endif
+
+    vec3 V = normalize(CameraPos.xyz - v_WorldPosition.xyz);
+    // Neubelt and Pettineo 2013, "Crafting a Next-gen Material Pipeline for The Order: 1886"
+    float NdotV = max(dot(N, V), 1e-4);
+
+    // Remapping [0,1] reflectance to F0
+    // See https://google.github.io/filament/Filament.html#materialsystem/parameterization/remapping
+    vec3 F0 = 0.16 * reflectance * reflectance * (1.0 - metallic) + output_color.rgb * metallic;
+
+    // Diffuse strength inversely related to metallicity
+    vec3 diffuseColor = output_color.rgb * (1.0 - metallic);
+
+    // accumulate color
+    vec3 light_accum = vec3(0.0);
+    for (int i = 0; i < int(NumLights.x) && i < MAX_LIGHTS; ++i) {
+        Light light = SceneLights[i];
+
+        vec3 lightDir = light.pos.xyz - v_WorldPosition.xyz;
+        vec3 L = normalize(lightDir);
+
+        float rangeAttenuation =
+            getDistanceAttenuation(lightDir, light.pos.w);
+
+        vec3 H = normalize(L + V);
+        float NoL = saturate(dot(N, L));
+        float NoH = saturate(dot(N, H));
+        float LoH = saturate(dot(L, H));
+
+        vec3 specular = specular(F0, roughness, H, NdotV, NoL, NoH, LoH);
+        vec3 diffuse = diffuseColor * Fd_Burley(roughness, NdotV, NoL, LoH);
+
+        // Lout = f(v,l) Φ / { 4 π d^2 }⟨n⋅l⟩
+        // where
+        // f(v,l) = (f_d(v,l) + f_r(v,l)) * light_color
+        // Φ is light intensity
+
+        // our rangeAttentuation = 1 / d^2 multiplied with an attenuation factor for smoothing at the edge of the non-physical maximum light radius
+        // It's not 100% clear where the 1/4π goes in the derivation, but we follow the filament shader and leave it out
+
+        // See https://google.github.io/filament/Filament.html#mjx-eqn-pointLightLuminanceEquation
+        // TODO compensate for energy loss https://google.github.io/filament/Filament.html#materialsystem/improvingthebrdfs/energylossinspecularreflectance
+        // light.color.rgb is premultiplied with light.intensity on the CPU
+        light_accum +=
+            ((diffuse + specular) * light.color.rgb) * (rangeAttenuation * NoL);
+    }
+
+    vec3 diffuse_ambient = EnvBRDFApprox(diffuseColor, 1.0, NdotV);
+    vec3 specular_ambient = EnvBRDFApprox(F0, perceptual_roughness, NdotV);
+
+    output_color.rgb = light_accum;
+    output_color.rgb += (diffuse_ambient + specular_ambient) * AmbientColor.xyz * occlusion;
+    output_color.rgb += emissive.rgb * output_color.a;
+
+    // tone_mapping
+    output_color.rgb = reinhard_luminance(output_color.rgb);
+    // Gamma correction.
+    // Not needed with sRGB buffer
+    // output_color.rgb = pow(output_color.rgb, vec3(1.0 / 2.2));
+#endif
+
+    o_Target = output_color;
+}

src/rendering/pbr.vert

@@ -0,0 +1,36 @@
+#version 450
+
+layout(location = 0) in vec3 Vertex_Position;
+layout(location = 1) in vec3 Vertex_Normal;
+layout(location = 2) in vec2 Vertex_Uv;
+
+#ifdef STANDARDMATERIAL_NORMAL_MAP
+layout(location = 3) in vec4 Vertex_Tangent;
+#endif
+
+layout(location = 0) out vec3 v_WorldPosition;
+layout(location = 1) out vec3 v_WorldNormal;
+layout(location = 2) out vec2 v_Uv;
+
+layout(set = 0, binding = 0) uniform CameraViewProj {
+    mat4 ViewProj;
+};
+
+#ifdef STANDARDMATERIAL_NORMAL_MAP
+layout(location = 3) out vec4 v_WorldTangent;
+#endif
+
+layout(set = 2, binding = 0) uniform Transform {
+    mat4 Model;
+};
+
+void main() {
+    vec4 world_position = Model * vec4(Vertex_Position, 1.0);
+    v_WorldPosition = world_position.xyz;
+    v_WorldNormal = mat3(Model) * Vertex_Normal;
+    v_Uv = Vertex_Uv;
+#ifdef STANDARDMATERIAL_NORMAL_MAP
+    v_WorldTangent = vec4(mat3(Model) * Vertex_Tangent.xyz, Vertex_Tangent.w);
+#endif
+    gl_Position = ViewProj * world_position;
+}

src/rendering/pipeline.rs

@@ -0,0 +1,58 @@
+use bevy::asset::Assets;
+use bevy::render::{
+    pipeline::{
+        BlendFactor, BlendOperation, BlendState, ColorTargetState, ColorWrite, CompareFunction,
+        DepthBiasState, DepthStencilState, PipelineDescriptor, StencilFaceState, StencilState,
+    },
+    shader::{Shader, ShaderStage, ShaderStages},
+    texture::TextureFormat,
+};
+
+// pub const PBR_PIPELINE_HANDLE: HandleUntyped =
+//     HandleUntyped::weak_from_u64(PipelineDescriptor::TYPE_UUID, 13148362314012771389);
+
+pub(crate) fn build_pbr_pipeline(shaders: &mut Assets<Shader>) -> PipelineDescriptor {
+    PipelineDescriptor {
+        depth_stencil: Some(DepthStencilState {
+            format: TextureFormat::Depth32Float,
+            depth_write_enabled: true,
+            depth_compare: CompareFunction::Less,
+            stencil: StencilState {
+                front: StencilFaceState::IGNORE,
+                back: StencilFaceState::IGNORE,
+                read_mask: 0,
+                write_mask: 0,
+            },
+            bias: DepthBiasState {
+                constant: 0,
+                slope_scale: 0.0,
+                clamp: 0.0,
+            },
+            clamp_depth: false,
+        }),
+        color_target_states: vec![ColorTargetState {
+            format: TextureFormat::default(),
+            color_blend: BlendState {
+                src_factor: BlendFactor::SrcAlpha,
+                dst_factor: BlendFactor::OneMinusSrcAlpha,
+                operation: BlendOperation::Add,
+            },
+            alpha_blend: BlendState {
+                src_factor: BlendFactor::One,
+                dst_factor: BlendFactor::One,
+                operation: BlendOperation::Add,
+            },
+            write_mask: ColorWrite::ALL,
+        }],
+        ..PipelineDescriptor::new(ShaderStages {
+            vertex: shaders.add(Shader::from_glsl(
+                ShaderStage::Vertex,
+                include_str!("pbr.vert"),
+            )),
+            fragment: Some(shaders.add(Shader::from_glsl(
+                ShaderStage::Fragment,
+                include_str!("pbr.frag"),
+            ))),
+        })
+    }
+}