Implement outlines for line renderer & use them for select & hover of…

… "line-like" primitives in Viewer (#1553)

* line batches support for outline masks
* Allow outlines for individual line strip ranges
* tweak selection outline style a bit
* change outline depth test for overwritability by same depth value
* rename outline_mask to outline_mask_ids

Cargo.toml

@@ -61,6 +61,7 @@ egui_dock = "0.4"
 egui_extras = "0.21.0"
 egui-wgpu = "0.21.0"
 emath = "0.21.0"
+enumset = "1.0.12"
 epaint = "0.21.0"
 glam = "0.22"
 gltf = "1.1"

crates/re_renderer/Cargo.toml

@@ -50,6 +50,7 @@ bytemuck = { version = "1.12", features = ["derive"] }
 clean-path = "0.2"
 document-features = "0.2"
 ecolor = { workspace = true, features = ["bytemuck"] }
+enumset.workspace = true
 glam = { workspace = true, features = ["bytemuck"] }
 half = { workspace = true, features = ["bytemuck"] }
 itertools = "0.10"

crates/re_renderer/examples/outlines.rs

@@ -14,7 +14,7 @@ struct Outlines {
 }
 
 struct MeshProperties {
-    outline_mask: OutlineMaskPreference,
+    outline_mask_ids: OutlineMaskPreference,
     position: glam::Vec3,
     rotation: glam::Quat,
 }
@@ -89,17 +89,17 @@ impl framework::Example for Outlines {
 
         let mesh_properties = [
             MeshProperties {
-                outline_mask: outline_mask_large_mesh,
+                outline_mask_ids: outline_mask_large_mesh,
                 position: glam::Vec3::ZERO,
                 rotation: glam::Quat::IDENTITY,
             },
             MeshProperties {
-                outline_mask: OutlineMaskPreference::some(1, 0),
+                outline_mask_ids: OutlineMaskPreference::some(1, 0),
                 position: glam::vec3(2.0, 0.0, -3.0),
                 rotation: glam::Quat::from_rotation_y(seconds_since_startup),
             },
             MeshProperties {
-                outline_mask: OutlineMaskPreference::some(0, 1),
+                outline_mask_ids: OutlineMaskPreference::some(0, 1),
                 position: glam::vec3(-2.0, 1.0, 3.0),
                 rotation: glam::Quat::from_rotation_x(seconds_since_startup),
             },
@@ -117,7 +117,7 @@ impl framework::Example for Outlines {
                             props.rotation,
                             props.position,
                         ) * instance.world_from_mesh,
-                        outline_mask: props.outline_mask,
+                        outline_mask_ids: props.outline_mask_ids,
                         ..Default::default()
                     })
             })

crates/re_renderer/shader/instanced_mesh.wgsl

@@ -20,7 +20,7 @@ struct VertexOut {
     @location(2) additive_tint_rgb: Vec3,
 
     @location(3) @interpolate(flat)
-    outline_mask: UVec2,
+    outline_mask_ids: UVec2,
 };
 
 @vertex
@@ -41,7 +41,7 @@ fn vs_main(in_vertex: VertexIn, in_instance: InstanceIn) -> VertexOut {
     out.texcoord = in_vertex.texcoord;
     out.normal_world_space = world_normal;
     out.additive_tint_rgb = linear_from_srgb(in_instance.additive_tint_srgb.rgb);
-    out.outline_mask = in_instance.outline_mask;
+    out.outline_mask_ids = in_instance.outline_mask_ids;
 
     return out;
 }
@@ -63,5 +63,5 @@ fn fs_main_shaded(in: VertexOut) -> @location(0) Vec4 {
 
 @fragment
 fn fs_main_outline_mask(in: VertexOut) -> @location(0) UVec2 {
-    return in.outline_mask;
+    return in.outline_mask_ids;
 }

crates/re_renderer/shader/lines.wgsl

@@ -13,6 +13,7 @@ var position_data_texture: texture_2d<u32>;
 
 struct BatchUniformBuffer {
     world_from_obj: Mat4,
+    outline_mask_ids: UVec2,
 };
 @group(2) @binding(0)
 var<uniform> batch: BatchUniformBuffer;
@@ -222,9 +223,7 @@ fn vs_main(@builtin(vertex_index) vertex_idx: u32) -> VertexOut {
     return out;
 }
 
-@fragment
-fn fs_main(in: VertexOut) -> @location(0) Vec4 {
-
+fn compute_coverage(in: VertexOut) -> f32{
     var coverage = 1.0;
     if has_any_flag(in.currently_active_flags, CAP_START_ROUND | CAP_END_ROUND) {
         let distance_to_skeleton = length(in.position_world - in.closest_strip_position);
@@ -234,11 +233,17 @@ fn fs_main(in: VertexOut) -> @location(0) Vec4 {
         // If we do only outwards, rectangle outlines won't line up nicely
         let half_pixel_world_size = pixel_world_size * 0.5;
         let signed_distance_to_border = distance_to_skeleton - in.active_radius;
-        if signed_distance_to_border > half_pixel_world_size {
-            discard;
-        }
         coverage = 1.0 - saturate((signed_distance_to_border + half_pixel_world_size) / pixel_world_size);
     }
+    return coverage;
+}
+
+@fragment
+fn fs_main(in: VertexOut) -> @location(0) Vec4 {
+    var coverage = compute_coverage(in);
+    if coverage < 0.00001 {
+        discard;
+    }
 
     // TODO(andreas): lighting setup
     var shading = 1.0;
@@ -250,3 +255,15 @@ fn fs_main(in: VertexOut) -> @location(0) Vec4 {
 
     return Vec4(in.color.rgb * shading, coverage);
 }
+
+@fragment
+fn fs_main_outline_mask(in: VertexOut) -> @location(0) UVec2 {
+    // Output is an integer target, can't use coverage therefore.
+    // But we still want to discard fragments where coverage is low.
+    // Since the outline extends a bit, a very low cut off tends to look better.
+    var coverage = compute_coverage(in);
+    if coverage < 1.0 {
+        discard;
+    }
+    return batch.outline_mask_ids;
+}

crates/re_renderer/shader/mesh_vertex.wgsl

@@ -16,5 +16,5 @@ struct InstanceIn {
     @location(7) world_from_mesh_normal_row_1: Vec3,
     @location(8) world_from_mesh_normal_row_2: Vec3,
     @location(9) additive_tint_srgb: Vec4,
-    @location(10) outline_mask: UVec2,
+    @location(10) outline_mask_ids: UVec2,
 };

crates/re_renderer/src/allocator/uniform_buffer_fill.rs

@@ -46,6 +46,10 @@ pub fn create_and_fill_uniform_buffer_batch<T: bytemuck::Pod>(
     #[allow(clippy::let_unit_value)]
     let _ = UniformBufferAlignmentCheck::<T>::CHECK;
 
+    if content.len() == 0 {
+        return vec![];
+    }
+
     let num_buffers = content.len() as u64;
     let element_size = std::mem::size_of::<T>() as u64;
 

crates/re_renderer/src/line_strip_builder.rs

@@ -1,5 +1,10 @@
+use std::ops::Range;
+
 use crate::{
-    renderer::{LineBatchInfo, LineDrawData, LineStripFlags, LineStripInfo, LineVertex},
+    renderer::{
+        LineBatchInfo, LineDrawData, LineStripFlags, LineStripInfo, LineVertex,
+        OutlineMaskPreference,
+    },
     Color32, DebugLabel, Size,
 };
 
@@ -33,6 +38,8 @@ where
             label: label.into(),
             world_from_obj: glam::Mat4::IDENTITY,
             line_vertex_count: 0,
+            overall_outline_mask_ids: OutlineMaskPreference::NONE,
+            additional_outline_mask_ids_vertex_ranges: Vec::new(),
         });
 
         LineBatchBuilder(self)
@@ -135,23 +142,35 @@ where
         self
     }
 
+    /// Sets an outline mask for every element in the batch.
+    #[inline]
+    pub fn outline_mask_ids(mut self, outline_mask_ids: OutlineMaskPreference) -> Self {
+        self.batch_mut().overall_outline_mask_ids = outline_mask_ids;
+        self
+    }
+
     /// Adds a 3D series of line connected points.
     pub fn add_strip(
         &mut self,
         points: impl Iterator<Item = glam::Vec3>,
     ) -> LineStripBuilder<'_, PerStripUserData> {
-        let old_len = self.0.strips.len();
-        let strip_index = old_len as _;
+        let old_strip_count = self.0.strips.len();
+        let old_vertex_count = self.0.vertices.len();
+        let strip_index = old_strip_count as _;
 
         self.add_vertices(points, strip_index);
+        let new_vertex_count = self.0.vertices.len();
 
         debug_assert_eq!(self.0.strips.len(), self.0.strip_user_data.len());
         self.0.strips.push(LineStripInfo::default());
         self.0.strip_user_data.push(PerStripUserData::default());
+        let new_strip_count = self.0.strips.len();
 
         LineStripBuilder {
-            strips: &mut self.0.strips[old_len..],
-            user_data: &mut self.0.strip_user_data[old_len..],
+            builder: self.0,
+            outline_mask_ids: OutlineMaskPreference::NONE,
+            vertex_range: old_vertex_count..new_vertex_count,
+            strip_range: old_strip_count..new_strip_count,
         }
     }
 
@@ -170,18 +189,19 @@ where
         &mut self,
         segments: impl Iterator<Item = (glam::Vec3, glam::Vec3)>,
     ) -> LineStripBuilder<'_, PerStripUserData> {
-        let mut num_strips = self.0.strips.len() as u32;
+        let old_strip_count = self.0.strips.len();
+        let old_vertex_count = self.0.vertices.len();
+        let mut strip_index = old_strip_count as u32;
 
         // It's tempting to assign the same strip to all vertices, after all they share
         // color/radius/tag properties.
         // However, if we don't assign different strip indices, we don't know when a strip (==segment) starts and ends.
         for (a, b) in segments {
-            self.add_vertices([a, b].into_iter(), num_strips);
-            num_strips += 1;
+            self.add_vertices([a, b].into_iter(), strip_index);
+            strip_index += 1;
         }
-
-        let old_len = self.0.strips.len();
-        let num_strips_added = num_strips as usize - old_len;
+        let new_vertex_count = self.0.vertices.len();
+        let num_strips_added = strip_index as usize - old_strip_count;
 
         debug_assert_eq!(self.0.strips.len(), self.0.strip_user_data.len());
         self.0
@@ -190,10 +210,13 @@ where
         self.0
             .strip_user_data
             .extend(std::iter::repeat(PerStripUserData::default()).take(num_strips_added));
+        let new_strip_count = self.0.strips.len();
 
         LineStripBuilder {
-            strips: &mut self.0.strips[old_len..],
-            user_data: &mut self.0.strip_user_data[old_len..],
+            builder: self.0,
+            outline_mask_ids: OutlineMaskPreference::NONE,
+            vertex_range: old_vertex_count..new_vertex_count,
+            strip_range: old_strip_count..new_strip_count,
         }
     }
 
@@ -345,8 +368,10 @@ where
 }
 
 pub struct LineStripBuilder<'a, PerStripUserData> {
-    strips: &'a mut [LineStripInfo],
-    user_data: &'a mut [PerStripUserData],
+    builder: &'a mut LineStripSeriesBuilder<PerStripUserData>,
+    outline_mask_ids: OutlineMaskPreference,
+    vertex_range: Range<usize>,
+    strip_range: Range<usize>,
 }
 
 impl<'a, PerStripUserData> LineStripBuilder<'a, PerStripUserData>
@@ -355,36 +380,60 @@ where
 {
     #[inline]
     pub fn radius(self, radius: Size) -> Self {
-        for strip in self.strips.iter_mut() {
+        for strip in self.builder.strips[self.strip_range.clone()].iter_mut() {
             strip.radius = radius;
         }
         self
     }
 
     #[inline]
     pub fn color(self, color: Color32) -> Self {
-        for strip in self.strips.iter_mut() {
+        for strip in self.builder.strips[self.strip_range.clone()].iter_mut() {
             strip.color = color;
         }
         self
     }
 
     #[inline]
     pub fn flags(self, flags: LineStripFlags) -> Self {
-        for strip in self.strips.iter_mut() {
+        for strip in self.builder.strips[self.strip_range.clone()].iter_mut() {
             strip.flags = flags;
         }
         self
     }
 
+    /// Sets an individual outline mask ids.
+    /// Note that this has a relatively high performance impact.
+    #[inline]
+    pub fn outline_mask_ids(mut self, outline_mask_ids: OutlineMaskPreference) -> Self {
+        self.outline_mask_ids = outline_mask_ids;
+        self
+    }
+
     /// Adds user data for every strip this builder adds.
     ///
     /// User data is currently not available on the GPU.
     #[inline]
     pub fn user_data(self, user_data: PerStripUserData) -> Self {
-        for d in self.user_data.iter_mut() {
+        for d in self.builder.strip_user_data[self.strip_range.clone()].iter_mut() {
             *d = user_data.clone();
         }
         self
     }
 }
+
+impl<'a, PerStripUserData> Drop for LineStripBuilder<'a, PerStripUserData> {
+    fn drop(&mut self) {
+        if self.outline_mask_ids.is_some() {
+            self.builder
+                .batches
+                .last_mut()
+                .unwrap()
+                .additional_outline_mask_ids_vertex_ranges
+                .push((
+                    self.vertex_range.start as u32..self.vertex_range.end as u32,
+                    self.outline_mask_ids,
+                ));
+        }
+    }
+}