From d221242e053ea8ae968a3611e488aaffdf9b34bd Mon Sep 17 00:00:00 2001
From: Urho Laukkarinen <urho.laukkarinen@gmail.com>
Date: Thu, 1 Feb 2024 21:11:12 +0200
Subject: [PATCH] GizmoResult::value is now optional

---
 demo/src/main.rs            | 23 ++++++++++++++---------
 src/lib.rs                  |  2 +-
 src/subgizmo/arcball.rs     | 14 ++++++--------
 src/subgizmo/rotation.rs    |  6 ++++--
 src/subgizmo/scale.rs       |  2 +-
 src/subgizmo/translation.rs |  2 +-
 6 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/demo/src/main.rs b/demo/src/main.rs
index c4a94db..780b98c 100644
--- a/demo/src/main.rs
+++ b/demo/src/main.rs
@@ -304,15 +304,20 @@ fn instructions_text(ui: &Ui) {
 }
 
 fn show_gizmo_status(ui: &Ui, response: GizmoResult) {
-    let length = Vec3::from(response.value).length();
-
-    let text = match response.mode {
-        GizmoMode::Rotate => format!("{:.1}°, {:.2} rad", length.to_degrees(), length),
-
-        GizmoMode::Translate | GizmoMode::Scale => format!(
-            "dX: {:.2}, dY: {:.2}, dZ: {:.2}",
-            response.value[0], response.value[1], response.value[2]
-        ),
+    let text = if let Some(value) = response.value {
+        match response.mode {
+            GizmoMode::Rotate => {
+                let length = Vec3::from(value).length();
+                format!("{:.1}°, {:.2} rad", length.to_degrees(), length)
+            }
+
+            GizmoMode::Translate | GizmoMode::Scale => format!(
+                "dX: {:.2}, dY: {:.2}, dZ: {:.2}",
+                value[0], value[1], value[2]
+            ),
+        }
+    } else {
+        String::new()
     };
 
     let rect = ui.clip_rect();
diff --git a/src/lib.rs b/src/lib.rs
index d6f0ee8..75ded21 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -416,7 +416,7 @@ pub struct GizmoResult {
     /// Mode of the active subgizmo
     pub mode: GizmoMode,
     /// Total scale, rotation or translation of the current gizmo activation, depending on mode
-    pub value: [f32; 3],
+    pub value: Option<[f32; 3]>,
 }
 
 impl GizmoResult {
diff --git a/src/subgizmo/arcball.rs b/src/subgizmo/arcball.rs
index 7115d53..fb6871b 100644
--- a/src/subgizmo/arcball.rs
+++ b/src/subgizmo/arcball.rs
@@ -10,7 +10,7 @@ pub(crate) type ArcballSubGizmo = SubGizmoConfig<Arcball>;
 
 #[derive(Default, Debug, Copy, Clone)]
 pub(crate) struct ArcballState {
-    last: Pos2,
+    last_pos: Pos2,
 }
 
 impl WidgetData for ArcballState {}
@@ -31,7 +31,7 @@ impl SubGizmo for ArcballSubGizmo {
         }
 
         self.update_state_with(ui, |state: &mut ArcballState| {
-            state.last = ray.screen_pos;
+            state.last_pos = ray.screen_pos;
         });
 
         Some(pick_result.t)
@@ -40,14 +40,12 @@ impl SubGizmo for ArcballSubGizmo {
     fn update(&mut self, ui: &Ui, ray: Ray) -> Option<GizmoResult> {
         let state = self.state(ui);
 
-        let dir = ray.screen_pos - state.last;
-
-        // Not a typical ArcBall rotation, but instead always rotates the object in the direction of mouse movement
+        let dir = ray.screen_pos - state.last_pos;
 
         let quat = if dir.length_sq() > f32::EPSILON {
             let mat = self.config.view_projection.inverse();
             let a = screen_to_world(self.config.viewport, mat, ray.screen_pos, 0.0);
-            let b = screen_to_world(self.config.viewport, mat, state.last, 0.0);
+            let b = screen_to_world(self.config.viewport, mat, state.last_pos, 0.0);
             let origin = self.config.view_forward();
             let a = (a - origin).normalize();
             let b = (b - origin).normalize();
@@ -58,7 +56,7 @@ impl SubGizmo for ArcballSubGizmo {
         };
 
         self.update_state_with(ui, |state: &mut ArcballState| {
-            state.last = ray.screen_pos;
+            state.last_pos = ray.screen_pos;
         });
 
         let new_rotation = quat * self.config.rotation;
@@ -68,7 +66,7 @@ impl SubGizmo for ArcballSubGizmo {
             rotation: new_rotation.as_f32().into(),
             translation: self.config.translation.as_vec3().into(),
             mode: GizmoMode::Rotate,
-            value: [0.0; 3], // TODO
+            value: None,
         })
     }
 
diff --git a/src/subgizmo/rotation.rs b/src/subgizmo/rotation.rs
index d5d016d..00d6e44 100644
--- a/src/subgizmo/rotation.rs
+++ b/src/subgizmo/rotation.rs
@@ -110,8 +110,10 @@ impl SubGizmo for RotationSubGizmo {
             rotation: new_rotation.as_f32().into(),
             translation: self.config.translation.as_vec3().into(),
             mode: GizmoMode::Rotate,
-            value: (gizmo_normal(&self.config, self.direction).as_vec3() * state.current_delta)
-                .to_array(),
+            value: Some(
+                (gizmo_normal(&self.config, self.direction).as_vec3() * state.current_delta)
+                    .to_array(),
+            ),
         })
     }
 
diff --git a/src/subgizmo/scale.rs b/src/subgizmo/scale.rs
index 0b2afd9..65a9bf3 100644
--- a/src/subgizmo/scale.rs
+++ b/src/subgizmo/scale.rs
@@ -89,7 +89,7 @@ impl SubGizmo for ScaleSubGizmo {
             rotation: self.config.rotation.as_f32().into(),
             translation: self.config.translation.as_vec3().into(),
             mode: GizmoMode::Scale,
-            value: offset.as_vec3().to_array(),
+            value: Some(offset.as_vec3().to_array()),
         })
     }
 
diff --git a/src/subgizmo/translation.rs b/src/subgizmo/translation.rs
index ffa2ccf..4b5a195 100644
--- a/src/subgizmo/translation.rs
+++ b/src/subgizmo/translation.rs
@@ -95,7 +95,7 @@ impl SubGizmo for TranslationSubGizmo {
             rotation: self.config.rotation.as_f32().into(),
             translation: new_translation.as_vec3().into(),
             mode: GizmoMode::Translate,
-            value: state.current_delta.as_vec3().to_array(),
+            value: Some(state.current_delta.as_vec3().to_array()),
         })
     }