feat(render): add scene environment pipeline

src/scene/camera_ops.rs

@@ -405,7 +405,7 @@ impl Scene {
         model_space: bool,
     ) -> bool {
         let _ = model_space;
-        let Some(cam) = self.camera_from_view(
+        let Some(cam) = self.camera_from_view_mode(
             view.direction,
             view.target,
             acadrust::types::Vector2 {
@@ -414,6 +414,8 @@ impl Scene {
             },
             view.height,
             view.twist_angle,
+            view.perspective,
+            view.lens_length,
         ) else {
             return false;
         };
@@ -463,16 +465,15 @@ impl Scene {
     /// their already-effective `view_target` / `view_center` / `view_height`.
     ///
     /// Returns `None` for a zero `view_height` (an uninitialised entry).
-    pub(super) fn camera_from_view(
+    pub(super) fn camera_from_view_mode(
         &self,
         view_direction: acadrust::types::Vector3,
         view_target: acadrust::types::Vector3,
         view_center: acadrust::types::Vector2,
         view_height: f64,
         twist: f64,
-        // Subtracted from `view_target` to reach wire-space. Model views pass
-        // `[0.0_f64; 3]`; paper-space views (whose entities carry no
-        // offset) pass `[0; 3]`.
+        perspective: bool,
+        lens_length: f64,
     ) -> Option<Camera> {
         if view_height.abs() < 1e-9 {
             return None;
@@ -516,14 +517,26 @@ impl Scene {
         let target = base
             + view_right.as_dvec3() * view_center.x
             + view_up.as_dvec3() * view_center.y;
-        let fov_y = 45.0_f32.to_radians();
+        let lens_length = lens_length.max(1.0) as f32;
+        // The saved-view convention uses a 24 mm vertical aperture. This is
+        // the inverse of the projection path's documented
+        // `distance = view_height * lens / 24` relation.
+        let fov_y = if perspective {
+            2.0 * (12.0 / lens_length).atan()
+        } else {
+            45.0_f32.to_radians()
+        };
         let distance = ((view_height as f32 / 2.0) / (fov_y * 0.5).tan()).max(0.001);
         Some(Camera {
             target,
             rotation,
             distance,
             fov_y,
-            projection: view::camera::Projection::Orthographic,
+            projection: if perspective {
+                view::camera::Projection::Perspective
+            } else {
+                view::camera::Projection::Orthographic
+            },
             yaw,
             pitch,
             // Sized from the saved view height (not a zoom-scaled range) so a
@@ -544,12 +557,14 @@ impl Scene {
 
     /// Decode a VPort table entry (model-space tiled view) into a `Camera`.
     fn camera_from_vport(&self, vp: &acadrust::tables::VPort) -> Option<Camera> {
-        self.camera_from_view(
+        self.camera_from_view_mode(
             vp.view_direction,
             vp.view_target,
             vp.view_center,
             vp.view_height,
             vp.view_twist,
+            vp.perspective,
+            vp.lens_length,
         )
     }
 
@@ -580,6 +595,8 @@ impl Scene {
             z: view_dir.z as f64,
         };
         entry.view_height = view_height as f64;
+        entry.perspective = cam.projection == view::camera::Projection::Perspective;
+        entry.lens_length = (12.0 / (cam.fov_y * 0.5).tan().max(1e-6)) as f64;
         entry.view_center = acadrust::types::Vector2::ZERO;
         // Stored twist = -roll, matching the decoder (roll = -twist).
         entry.view_twist = -cam.roll() as f64;
@@ -796,7 +813,7 @@ impl Scene {
 
         // Paper-space entities carry no world_offset → decode with a zero
         // offset, through the same shared decoder (twist included).
-        let Some(cam) = self.camera_from_view(
+        let Some(cam) = self.camera_from_view_mode(
             vp.view_direction,
             vp.view_target,
             acadrust::types::Vector2 {
@@ -805,6 +822,8 @@ impl Scene {
             },
             vp.view_height,
             vp.twist_angle,
+            vp.status.perspective,
+            vp.lens_length,
         ) else {
             return false;
         };
@@ -847,6 +866,8 @@ impl Scene {
                 vp.view_direction = vd3;
                 vp.view_height = view_height as f64;
                 vp.view_twist = twist;
+                vp.perspective = cam.projection == view::camera::Projection::Perspective;
+                vp.lens_length = (12.0 / (cam.fov_y * 0.5).tan().max(1e-6)) as f64;
             }
 
             // Persist the tiled layout as duplicate `*Active` VPort entries.
@@ -878,6 +899,9 @@ impl Scene {
                 vp.view_direction = vd3;
                 vp.view_height = view_height as f64;
                 vp.twist_angle = twist;
+                vp.status.perspective =
+                    cam.projection == view::camera::Projection::Perspective;
+                vp.lens_length = (12.0 / (cam.fov_y * 0.5).tan().max(1e-6)) as f64;
             }
             true
         }
@@ -985,6 +1009,7 @@ impl Scene {
                 None,
                 scale,
                 self.annotation_all_visible(),
+                None,
             ) {
                 let is_infinite = Self::handle_from_wire_name(&wire.name)
                     .and_then(|handle| self.document.get_entity(handle))
@@ -1081,6 +1106,7 @@ impl Scene {
             None,
             scale,
             self.annotation_all_visible(),
+            None,
         );
         // Ray / XLine tessellate as ±DISPLAY_EXTENT display segments
         // (entities/ray.rs) — their endpoints are rendering artifacts, not