From 9f729cffee831eaee148e3a08e2e7c2394be39ab Mon Sep 17 00:00:00 2001
From: Andreas Reich <andreas@rerun.io>
Date: Tue, 2 Jul 2024 09:26:23 +0200
Subject: [PATCH] add tests & comments for point/scene distinction

---
 crates/re_renderer/src/size.rs               | 38 ++++++++++++++++++--
 crates/re_types/src/components/radius_ext.rs | 34 ++++++++++++++++++
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/crates/re_renderer/src/size.rs b/crates/re_renderer/src/size.rs
index 591988f65d33..6de8f69526a2 100644
--- a/crates/re_renderer/src/size.rs
+++ b/crates/re_renderer/src/size.rs
@@ -37,13 +37,15 @@ impl Size {
 
     /// Get the scene-size of this, if stored as a scene size.
     #[inline]
-    pub fn scene(&self) -> Option<f32> {
+    pub fn scene_units(&self) -> Option<f32> {
+        // Ensure negative zero is treated as a point size.
         self.0.is_sign_positive().then_some(self.0)
     }
 
     /// Get the point size of this, if stored as a point size.
     #[inline]
-    pub fn points(&self) -> Option<f32> {
+    pub fn ui_points(&self) -> Option<f32> {
+        // Ensure negative zero is treated as a point size.
         self.0.is_sign_negative().then_some(-self.0)
     }
 }
@@ -86,3 +88,35 @@ impl From<Size> for SizeHalf {
         Self(half::f16::from_f32(size.0))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::Size;
+
+    #[test]
+    fn scene_point_distinction() {
+        let size = Size(1.0);
+        assert_eq!(size.scene_units(), Some(1.0));
+        assert_eq!(size.ui_points(), None);
+
+        let size = Size(-1.0);
+        assert_eq!(size.scene_units(), None);
+        assert_eq!(size.ui_points(), Some(1.0));
+
+        let size = Size(f32::INFINITY);
+        assert_eq!(size.scene_units(), Some(f32::INFINITY));
+        assert_eq!(size.ui_points(), None);
+
+        let size = Size(f32::NEG_INFINITY);
+        assert_eq!(size.scene_units(), None);
+        assert_eq!(size.ui_points(), Some(f32::INFINITY));
+
+        let size = Size(0.0);
+        assert_eq!(size.scene_units(), Some(0.0));
+        assert_eq!(size.ui_points(), None);
+
+        let size = Size(-0.0);
+        assert_eq!(size.scene_units(), None);
+        assert_eq!(size.ui_points(), Some(0.0));
+    }
+}
diff --git a/crates/re_types/src/components/radius_ext.rs b/crates/re_types/src/components/radius_ext.rs
index 4f2a53c42dc3..6bf920283bf3 100644
--- a/crates/re_types/src/components/radius_ext.rs
+++ b/crates/re_types/src/components/radius_ext.rs
@@ -43,12 +43,46 @@ impl Radius {
     /// If this radius is in scene units, returns the radius in scene units.
     #[inline]
     pub fn scene_units(&self) -> Option<f32> {
+        // Ensure negative zero is treated as a point size.
         self.0.is_sign_positive().then_some(self.0)
     }
 
     /// If this radius is in ui points, returns the radius in ui points.
     #[inline]
     pub fn ui_points(&self) -> Option<f32> {
+        // Ensure negative zero is treated as a point size.
         self.0.is_sign_negative().then_some(-self.0)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::Radius;
+
+    #[test]
+    fn scene_point_distinction() {
+        let radius = Radius(1.0);
+        assert_eq!(radius.scene_units(), Some(1.0));
+        assert_eq!(radius.ui_points(), None);
+
+        let radius = Radius(-1.0);
+        assert_eq!(radius.scene_units(), None);
+        assert_eq!(radius.ui_points(), Some(1.0));
+
+        let radius = Radius(f32::INFINITY);
+        assert_eq!(radius.scene_units(), Some(f32::INFINITY));
+        assert_eq!(radius.ui_points(), None);
+
+        let radius = Radius(f32::NEG_INFINITY);
+        assert_eq!(radius.scene_units(), None);
+        assert_eq!(radius.ui_points(), Some(f32::INFINITY));
+
+        let radius = Radius(0.0);
+        assert_eq!(radius.scene_units(), Some(0.0));
+        assert_eq!(radius.ui_points(), None);
+
+        let radius = Radius(-0.0);
+        assert_eq!(radius.scene_units(), None);
+        assert_eq!(radius.ui_points(), Some(0.0));
+    }
+}