Add stub 3D gizmo

editor/Cargo.toml

@@ -8,7 +8,8 @@ bytemuck = "^1.0"
 crossbeam-channel = "^0.5"
 cyborg = { path = "../", features = ["legion"] }
 egui = "0.18"
-egui-winit = "0.18.0"
+egui-gizmo = "0.7"
+egui-winit = "0.18"
 egui_wgpu_backend = "0.18.0"
 glam = { version = "0.20", features = ["serde"] }
 gltf = { version = "1.0", features = ["utils"] }

editor/src/ui.rs

@@ -211,7 +211,7 @@ impl UserInterface {
             });
 
         egui::CentralPanel::default().show(ctx, |ui| {
-            ui.add(viewport);
+            viewport.show(ui);
             ui.heading("Viewport");
         });
     }
@@ -260,6 +260,7 @@ pub struct ViewportWidget {
     pub flycam: Flycam,
     pub width: u32,
     pub height: u32,
+    pub dragging: bool,
 }
 
 impl ViewportWidget {
@@ -269,21 +270,39 @@ impl ViewportWidget {
             flycam: Flycam::new(0.002, 10.0, 0.25),
             width: 640,
             height: 480,
+            dragging: false,
         }
     }
-}
 
-impl egui::Widget for &mut ViewportWidget {
-    fn ui(self, ui: &mut egui::Ui) -> egui::Response {
+    fn should_drag(
+        &self,
+        viewport: egui::Rect,
+        gizmo_active: bool,
+        pointer: &egui::PointerState,
+    ) -> bool {
+        if gizmo_active {
+            false
+        } else if !pointer.primary_down() {
+            false
+        } else if self.dragging {
+            true
+        } else if let Some(pos) = pointer.interact_pos() {
+            viewport.contains(pos)
+        } else {
+            false
+        }
+    }
+
+    fn show(&mut self, ui: &mut egui::Ui) {
         ui.style_mut().spacing.window_margin = egui::style::Margin::same(0.0);
         let rect = ui.max_rect();
-        let id = egui::Id::new("viewport_widget");
-        let sense = egui::Sense::click_and_drag();
-        let response = ui.interact(rect, id, sense);
 
         self.width = rect.width().round() as u32;
         self.height = rect.height().round() as u32;
 
+        self.flycam.resize(self.width, self.height);
+        self.flycam.update();
+
         use egui::{pos2, Color32, Mesh, Rect, Shape};
         let mut mesh = Mesh::with_texture(self.texture);
         let uv = Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0));
@@ -291,11 +310,22 @@ impl egui::Widget for &mut ViewportWidget {
         mesh.add_rect_with_uv(rect, uv, tint);
         ui.painter().add(Shape::mesh(mesh));
 
-        if response.dragged() {
-            let delta = response.drag_delta();
+        let gizmo = egui_gizmo::Gizmo::new("My gizmo")
+            .viewport(rect)
+            .view_matrix(self.flycam.get_view().to_cols_array_2d())
+            .projection_matrix(self.flycam.get_projection().to_cols_array_2d());
+
+        let gizmo = gizmo.interact(ui);
+
+        let input = ui.input();
+
+        self.dragging = self.should_drag(rect, gizmo.is_some(), &input.pointer);
+
+        if self.dragging {
+            let delta = input.pointer.delta();
             self.flycam.process_mouse(delta.x as f64, delta.y as f64);
 
-            for event in ui.input().events.iter() {
+            for event in input.events.iter() {
                 match event {
                     egui::Event::Key { key, pressed, .. } => {
                         use winit::event::{ElementState, VirtualKeyCode};
@@ -324,14 +354,9 @@ impl egui::Widget for &mut ViewportWidget {
                     _ => {}
                 }
             }
-        } else if response.drag_released() {
+        } else {
             self.flycam.defocus();
         }
-
-        self.flycam.resize(self.width, self.height);
-        self.flycam.update();
-
-        response
     }
 }
 

src/camera.rs

@@ -233,16 +233,21 @@ impl Flycam {
     pub fn get_eye(&self) -> [f32; 4] {
         self.position.extend(0.0).to_array()
     }
-
-    pub fn get_vp(&self) -> [[f32; 4]; 4] {
+    
+    pub fn get_view(&self) -> glam::Mat4 {
         // view matrix is inverted camera pose (world space to camera space)
         let rotation = Mat4::from_quat(self.get_orientation().inverse());
         let translation = Mat4::from_translation(-self.position);
-        let view = rotation * translation;
-
-        // perspective projection
-        let proj = Mat4::perspective_rh_gl(self.fovy, self.aspect, self.znear, self.zfar);
+        rotation * translation
+    }
+    
+    pub fn get_projection(&self) -> glam::Mat4 {
+        Mat4::perspective_rh_gl(self.fovy, self.aspect, self.znear, self.zfar)
+    }
 
+    pub fn get_vp(&self) -> [[f32; 4]; 4] {
+        let view = self.get_view();
+        let proj = self.get_projection();
         let vp = proj * view;
         vp.to_cols_array_2d()
     }