Added Depth-based Outlines

4 files changed, 41 insertions, 15 deletions

diff --git a/src/components.rs b/src/components.rs
index 22de86c..bdce6c9 100644
--- a/src/components.rs
+++ b/src/components.rs
@@ -1,7 +1,7 @@
 use bevy::{
+    core_pipeline::prepass::{DeferredPrepass, DepthPrepass, NormalPrepass},
     prelude::*,
     render::{extract_component::ExtractComponent, render_resource::ShaderType},
-    core_pipeline::prepass::{NormalPrepass, DepthPrepass, DeferredPrepass},
 };
 
 /// Component which, when inserted into an entity with a camera and normal prepass, enables an outline effect for that
@@ -14,20 +14,29 @@ pub struct OutlinePostProcessSettings {
     /// A threshold for normal differences, values below this threshold will not become outlines.
     /// Higher values will result in more outlines which may look better on smooth surfaces.
     normal_threshold: f32,
+    /// A threshold for depth differences (in units), values below this threshold will not become outlines.
+    /// Higher values will result in more outlines which may look better on smooth surfaces.
+    depth_threshold: f32,
     /// Whether to use adaptive outlines. White outlines will be drawn around darker objects, while black ones will be drawn around lighter ones.
     adaptive: u32,
-    /// Threshold of illumination for outlines to apply. Requires deferred prepass.
-    light_threshold: f32,
+    /// Near plane depth of camera, used for linearization of depth buffer values
+    pub(crate) camera_near: f32,
 }
 
 impl OutlinePostProcessSettings {
     /// Create a new instance with the given settings
-    pub fn new(weight: f32, normal_threshold: f32, adaptive: bool, light_threshold: f32) -> Self {
+    pub fn new(
+        weight: f32,
+        normal_threshold: f32,
+        depth_threshold: f32,
+        adaptive: bool,
+    ) -> Self {
         Self {
             weight,
             normal_threshold,
             adaptive: adaptive as u32,
-            light_threshold,
+            depth_threshold,
+            camera_near: 0.0,
         }
     }
 }
@@ -38,7 +47,8 @@ impl Default for OutlinePostProcessSettings {
             weight: 1.0,
             normal_threshold: 0.0,
             adaptive: 0,
-            light_threshold: 0.0,
+            depth_threshold: 0.05,
+            camera_near: 0.0,
         }
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 3040bff..f189cd4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,7 @@
 #![warn(missing_docs)]
 
 //! A plugin for the Bevy game engine which provides an outline post-process effect. The effect
-//! makes use of a normal prepass to generate outlines where differences in the normal buffer
+//! makes use of a normal and depth prepass to generate outlines where significant differences in the values
 //! occur.
 
 use bevy::{
@@ -9,12 +9,11 @@ use bevy::{
     core_pipeline::core_3d::graph::{Core3d, Node3d},
     prelude::*,
     render::{
-        extract_component::{ExtractComponentPlugin, UniformComponentPlugin},
-        render_graph::{RenderGraphApp, ViewNodeRunner},
-        RenderApp,
+        extract_component::{ExtractComponentPlugin, UniformComponentPlugin}, render_graph::{RenderGraphApp, ViewNodeRunner}, RenderApp
     },
 };
 
+use components::OutlinePostProcessSettings;
 pub use nodes::OutlineRenderLabel;
 
 /// Components used by this plugin.
@@ -32,7 +31,7 @@ impl Plugin for OutlinePostProcessPlugin {
         app.add_plugins((
             UniformComponentPlugin::<components::OutlinePostProcessSettings>::default(),
             ExtractComponentPlugin::<components::OutlinePostProcessSettings>::default(),
-        ));
+        )).add_systems(Update, update_shader_clip_planes);
 
         let Some(render_app) = app.get_sub_app_mut(RenderApp) else {
             return;
@@ -61,3 +60,15 @@ impl Plugin for OutlinePostProcessPlugin {
         render_app.init_resource::<resources::OutlinePostProcessPipeline>();
     }
 }
+
+fn update_shader_clip_planes(
+    mut settings_query: Query<(Ref<Projection>, &mut OutlinePostProcessSettings)>,
+) {
+    for (projection, mut settings) in settings_query.iter_mut() {
+        if projection.is_changed() {
+            if let Projection::Perspective(projection) = projection.into_inner() {
+                settings.camera_near = projection.near;
+            }
+        }
+    }
+}
diff --git a/src/nodes.rs b/src/nodes.rs
index 1c750c7..b2b4a22 100644
--- a/src/nodes.rs
+++ b/src/nodes.rs
@@ -57,8 +57,8 @@ impl ViewNode for OutlineRenderNode {
             return Ok(());
         };
 
-        let Some(deferred_buffer_view) = view_prepass_textures.deferred_view() else {
-            error!("Failed to get deferred buffer view");
+        let Some(depth_buffer_view) = view_prepass_textures.depth_view() else {
+            error!("Failed to get normal buffer view");
             return Ok(());
         };
 
@@ -72,7 +72,8 @@ impl ViewNode for OutlineRenderNode {
                 &render_pipeline.screen_sampler,
                 normal_buffer_view,
                 &render_pipeline.normal_sampler,
-                deferred_buffer_view,
+                depth_buffer_view,
+                &render_pipeline.depth_sampler,
                 uniform_binding,
             )),
         );
diff --git a/src/resources.rs b/src/resources.rs
index 072b21c..4460558 100644
--- a/src/resources.rs
+++ b/src/resources.rs
@@ -20,6 +20,7 @@ pub struct OutlinePostProcessPipeline {
     pub layout: BindGroupLayout,
     pub screen_sampler: Sampler,
     pub normal_sampler: Sampler,
+    pub depth_sampler: Sampler,
     pub pipeline_id: CachedRenderPipelineId,
 }
 
@@ -36,7 +37,8 @@ impl FromWorld for OutlinePostProcessPipeline {
                     sampler(SamplerBindingType::Filtering),
                     texture_2d(TextureSampleType::Float { filterable: true }),
                     sampler(SamplerBindingType::Filtering),
-                    texture_2d(TextureSampleType::Uint),
+                    texture_2d(TextureSampleType::Depth),
+                    sampler(SamplerBindingType::NonFiltering),
                     uniform_buffer::<components::OutlinePostProcessSettings>(false),
                 ),
             ),
@@ -44,6 +46,7 @@ impl FromWorld for OutlinePostProcessPipeline {
 
         let screen_sampler = render_device.create_sampler(&SamplerDescriptor::default());
         let normal_sampler = render_device.create_sampler(&SamplerDescriptor::default());
+        let depth_sampler = render_device.create_sampler(&SamplerDescriptor::default());
 
         let shader = world.resource::<AssetServer>().load::<Shader>(
             "embedded://bevy_outline_post_process/../assets/shaders/outline_post_process.wgsl",
@@ -77,6 +80,7 @@ impl FromWorld for OutlinePostProcessPipeline {
             layout,
             screen_sampler,
             normal_sampler,
+            depth_sampler,
             pipeline_id,
         }
     }