Fix noisy depth values in flat mode.

src/draw.rs

@@ -3,9 +3,7 @@ use bevy::prelude::*;
 use bevy::render::render_asset::RenderAssets;
 use bevy::render::render_phase::{DrawFunctions, RenderPhase, SetItemPipeline};
 use bevy::render::render_resource::{PipelineCache, SpecializedMeshPipelines};
-use bevy::render::renderer::RenderAdapterInfo;
 use bevy::render::view::{ExtractedView, RenderLayers};
-use wgpu_types::Backend;
 
 use crate::node::{OpaqueOutline, StencilOutline, TransparentOutline};
 use crate::pipeline::{OutlinePipeline, PassType, PipelineKey};
@@ -34,7 +32,6 @@ pub(crate) fn queue_outline_stencil_mesh(
     mut pipelines: ResMut<SpecializedMeshPipelines<OutlinePipeline>>,
     pipeline_cache: Res<PipelineCache>,
     render_meshes: Res<RenderAssets<Mesh>>,
-    adapter_info: Res<RenderAdapterInfo>,
     material_meshes: Query<(
         Entity,
         &Handle<Mesh>,
@@ -55,8 +52,7 @@ pub(crate) fn queue_outline_stencil_mesh(
 
     let base_key = PipelineKey::new()
         .with_msaa(*msaa)
-        .with_pass_type(PassType::Stencil)
+        .with_pass_type(PassType::Stencil);
-        .with_opengl_workaround(adapter_info.0.backend == Backend::Gl);
 
     for (view, mut stencil_phase, view_mask) in views.iter_mut() {
         let rangefinder = view.rangefinder3d();
@@ -112,7 +108,6 @@ pub(crate) fn queue_outline_volume_mesh(
     mut pipelines: ResMut<SpecializedMeshPipelines<OutlinePipeline>>,
     pipeline_cache: Res<PipelineCache>,
     render_meshes: Res<RenderAssets<Mesh>>,
-    adapter_info: Res<RenderAdapterInfo>,
     material_meshes: Query<(
         Entity,
         &Handle<Mesh>,
@@ -137,9 +132,7 @@ pub(crate) fn queue_outline_volume_mesh(
         .get_id::<DrawOutline>()
         .unwrap();
 
-    let base_key = PipelineKey::new()
+    let base_key = PipelineKey::new().with_msaa(*msaa);
-        .with_msaa(*msaa)
-        .with_opengl_workaround(adapter_info.0.backend == Backend::Gl);
 
     for (view, mut opaque_phase, mut transparent_phase, view_mask) in views.iter_mut() {
         let view_mask = view_mask.copied().unwrap_or_default();

src/fragment.wgsl

@@ -1,6 +1,6 @@
 struct FragmentOutput {
     @location(0) colour: vec4<f32>,
-#ifdef OPENGL_WORKAROUND
+#ifdef FLAT_DEPTH
     @builtin(frag_depth) frag_depth: f32,
 #endif
 };
@@ -16,8 +16,8 @@ var<uniform> fstage: OutlineFragmentUniform;
 #endif
 
 @fragment
-#ifdef OPENGL_WORKAROUND
+#ifdef FLAT_DEPTH
-fn fragment(@location(0) normalised_depth: f32) -> FragmentOutput {
+fn fragment(@location(0) @interpolate(flat) flat_depth: f32) -> FragmentOutput {
 #else
 fn fragment() -> FragmentOutput {
 #endif
@@ -25,8 +25,8 @@ fn fragment() -> FragmentOutput {
 #ifdef VOLUME
     out.colour = fstage.colour;
 #endif
-#ifdef OPENGL_WORKAROUND
+#ifdef FLAT_DEPTH
-    out.frag_depth = normalised_depth; 
+    out.frag_depth = flat_depth; 
 #endif
     return out;
 }

src/outline.wgsl

@@ -20,8 +20,8 @@ struct Vertex {
 
 struct VertexOutput {
     @builtin(position) position: vec4<f32>,
-#ifdef OPENGL_WORKAROUND
+#ifdef FLAT_DEPTH
-    @location(0) normalised_depth: f32,
+    @location(0) @interpolate(flat) flat_depth: f32,
 #endif
 };
 
@@ -93,11 +93,6 @@ fn vertex(vertex_no_morph: Vertex) -> VertexOutput {
     let model = mesh.model;
 #endif
     let clip_pos = view.view_proj * (model * vec4<f32>(vertex.position, 1.0));
-#ifdef FLAT_DEPTH
-    let out_z = model_origin_z(vstage.origin, view.view_proj) * clip_pos.w;
-#else
-    let out_z = clip_pos.z;
-#endif
 #ifdef OFFSET_ZERO
     let out_xy = clip_pos.xy;
 #else
@@ -106,9 +101,9 @@ fn vertex(vertex_no_morph: Vertex) -> VertexOutput {
     let out_xy = clip_pos.xy + ndc_delta;
 #endif
     var out: VertexOutput;
-    out.position = vec4<f32>(out_xy, out_z, clip_pos.w);
+    out.position = vec4<f32>(out_xy, clip_pos.zw);
-#ifdef OPENGL_WORKAROUND
+#ifdef FLAT_DEPTH
-    out.normalised_depth = 0.5 + 0.5 * (out_z / clip_pos.w);
+    out.flat_depth = model_origin_z(vstage.origin, view.view_proj);
 #endif
     return out;
 }

src/pipeline.rs

@@ -56,8 +56,7 @@ impl PipelineKey {
         depth_mode_int, set_depth_mode_int: 12, 11;
         pub offset_zero, set_offset_zero: 13;
         pub hdr_format, set_hdr_format: 14;
-        pub opengl_workaround, set_opengl_workaround: 15;
+        pub morph_targets, set_morph_targets: 15;
-        pub morph_targets, set_morph_targets: 16;
     }
 
     pub(crate) fn new() -> Self {
@@ -132,11 +131,6 @@ impl PipelineKey {
         self
     }
 
-    pub(crate) fn with_opengl_workaround(mut self, opengl_workaround: bool) -> Self {
-        self.set_opengl_workaround(opengl_workaround);
-        self
-    }
-
     pub(crate) fn with_morph_targets(mut self, morph_targets: bool) -> Self {
         self.set_morph_targets(morph_targets);
         self
@@ -269,7 +263,9 @@ impl SpecializedMeshPipeline for OutlinePipeline {
         bind_layouts.push(self.outline_view_bind_group_layout.clone());
         let cull_mode;
         if key.depth_mode() == DepthMode::Flat {
-            vertex_defs.push(ShaderDefVal::from("FLAT_DEPTH"));
+            let val = ShaderDefVal::from("FLAT_DEPTH");
+            vertex_defs.push(val.clone());
+            fragment_defs.push(val);
             cull_mode = Some(Face::Back);
         } else if key.pass_type() == PassType::Stencil {
             cull_mode = Some(Face::Back);
@@ -311,11 +307,6 @@ impl SpecializedMeshPipeline for OutlinePipeline {
                 bind_layouts.push(self.outline_volume_bind_group_layout.clone());
             }
         }
-        if key.opengl_workaround() {
-            let val = ShaderDefVal::from("OPENGL_WORKAROUND");
-            vertex_defs.push(val.clone());
-            fragment_defs.push(val);
-        }
         let buffers = vec![layout.get_layout(&buffer_attrs)?];
         Ok(RenderPipelineDescriptor {
             vertex: VertexState {
@@ -345,17 +336,7 @@ impl SpecializedMeshPipeline for OutlinePipeline {
                 depth_write_enabled: true,
                 depth_compare: CompareFunction::Greater,
                 stencil: StencilState::default(),
-                bias: if key.depth_mode() == DepthMode::Flat && key.pass_type() == PassType::Stencil
+                bias: DepthBiasState::default(),
-                {
-                    DepthBiasState {
-                        // Values determined empirically
-                        constant: 3,
-                        slope_scale: 1.0,
-                        ..default()
-                    }
-                } else {
-                    default()
-                },
             }),
             multisample: MultisampleState {
                 count: key.msaa().samples(),