Correcting InheritableVariable::visit and physics integration parameters dt (#844)

editor/src/scene/mod.rs

@@ -211,10 +211,6 @@ impl GameScene {
             scene_content_root,
         );
 
-        // Freeze physics simulation in while editing scene by setting time step to zero.
-        scene.graph.physics.integration_parameters.dt = Some(0.0);
-        scene.graph.physics2d.integration_parameters.dt = Some(0.0);
-
         GameScene {
             editor_objects_root,
             scene_content_root,
@@ -224,6 +220,8 @@ impl GameScene {
             clipboard: Default::default(),
             preview_camera: Default::default(),
             graph_switches: GraphUpdateSwitches {
+                // Freeze physics simulation while editing scene by setting time step to zero.
+                physics_dt: false,
                 physics2d: true,
                 physics: true,
                 // Prevent engine to update lifetime of the nodes and to delete "dead" nodes. Otherwise

fyrox-core/src/variable.rs

@@ -337,8 +337,15 @@ where
         if visitor.is_reading() {
             // Try to visit inner value first, this is very useful if user decides to make their
             // variable inheritable, but still keep backward compatibility.
-            visited = self.value.visit(name, visitor).is_ok();
-            self.flags.get_mut().insert(VariableFlags::MODIFIED);
+            let has_flags = if let Ok(mut region) = visitor.enter_region(name) {
+                self.flags.get_mut().0.visit("Flags", &mut region).is_ok()
+            } else {
+                false
+            };
+            if !has_flags {
+                visited = self.value.visit(name, visitor).is_ok();
+                self.flags.get_mut().insert(VariableFlags::MODIFIED);
+            }
         }
 
         if !visited {

fyrox-impl/src/scene/dim2/physics.rs

@@ -618,12 +618,33 @@ impl PhysicsWorld {
         }
     }
 
-    pub(crate) fn update(&mut self, dt: f32) {
+    /// Update the physics pipeline with a timestep of the given length.
+    ///
+    /// * `dt`: The amount of time that has passed since the previous update.
+    ///   This may be overriden by [`PhysicsWorld::integration_parameters`] if
+    ///   `integration_parameters.dt` is `Some`, in which case that value is used
+    ///   instead of this argument.
+    /// * `dt_enabled`: If this is true then `dt` is used as usual, but if this is false
+    ///   then both the `dt` argument and `integration_parameters.dt` are ignored and
+    ///   a `dt` of zero is used instead, freezing all physics. This corresponds to the
+    ///   [`GraphUpdateSwitches::physics_dt`](crate::scene::graph::GraphUpdateSwitches::physics_dt).
+    pub(crate) fn update(&mut self, dt: f32, dt_enabled: bool) {
         let time = instant::Instant::now();
+        let parameter_dt = self.integration_parameters.dt;
+        let parameter_dt = if parameter_dt == Some(0.0) {
+            None
+        } else {
+            parameter_dt
+        };
+        let dt = if dt_enabled {
+            parameter_dt.unwrap_or(dt)
+        } else {
+            0.0
+        };
 
         if *self.enabled {
             let integration_parameters = rapier2d::dynamics::IntegrationParameters {
-                dt: self.integration_parameters.dt.unwrap_or(dt),
+                dt,
                 min_ccd_dt: self.integration_parameters.min_ccd_dt,
                 contact_damping_ratio: self.integration_parameters.contact_damping_ratio,
                 contact_natural_frequency: self.integration_parameters.contact_natural_frequency,

fyrox-impl/src/scene/graph/mod.rs

@@ -270,6 +270,8 @@ fn clear_links(mut node: Node) -> Node {
 /// A set of switches that allows you to disable a particular step of graph update pipeline.
 #[derive(Clone, PartialEq, Eq)]
 pub struct GraphUpdateSwitches {
+    /// Enables the physics update to have a non-zero `dt`.
+    pub physics_dt: bool,
     /// Enables or disables update of the 2D physics.
     pub physics2d: bool,
     /// Enables or disables update of the 3D physics.
@@ -287,6 +289,7 @@ pub struct GraphUpdateSwitches {
 impl Default for GraphUpdateSwitches {
     fn default() -> Self {
         Self {
+            physics_dt: true,
             physics2d: true,
             physics: true,
             node_overrides: Default::default(),
@@ -1200,13 +1203,13 @@ impl Graph {
 
         if switches.physics {
             self.physics.performance_statistics.reset();
-            self.physics.update(dt);
+            self.physics.update(dt, switches.physics_dt);
             self.performance_statistics.physics = self.physics.performance_statistics.clone();
         }
 
         if switches.physics2d {
             self.physics2d.performance_statistics.reset();
-            self.physics2d.update(dt);
+            self.physics2d.update(dt, switches.physics_dt);
             self.performance_statistics.physics2d = self.physics2d.performance_statistics.clone();
         }
 

fyrox-impl/src/scene/graph/physics.rs

@@ -1101,12 +1101,33 @@ impl PhysicsWorld {
         }
     }
 
-    pub(super) fn update(&mut self, dt: f32) {
+    /// Update the physics pipeline with a timestep of the given length.
+    ///
+    /// * `dt`: The amount of time that has passed since the previous update.
+    ///   This may be overriden by [`PhysicsWorld::integration_parameters`] if
+    ///   `integration_parameters.dt` is `Some`, in which case that value is used
+    ///   instead of this argument.
+    /// * `dt_enabled`: If this is true then `dt` is used as usual, but if this is false
+    ///   then both the `dt` argument and `integration_parameters.dt` are ignored and
+    ///   a `dt` of zero is used instead, freezing all physics. This corresponds to the
+    ///   [`GraphUpdateSwitches::physics_dt`](crate::scene::graph::GraphUpdateSwitches::physics_dt).
+    pub(super) fn update(&mut self, dt: f32, dt_enabled: bool) {
         let time = instant::Instant::now();
+        let parameter_dt = self.integration_parameters.dt;
+        let parameter_dt = if parameter_dt == Some(0.0) {
+            None
+        } else {
+            parameter_dt
+        };
+        let dt = if dt_enabled {
+            parameter_dt.unwrap_or(dt)
+        } else {
+            0.0
+        };
 
         if *self.enabled {
             let integration_parameters = rapier3d::dynamics::IntegrationParameters {
-                dt: self.integration_parameters.dt.unwrap_or(dt),
+                dt,
                 min_ccd_dt: self.integration_parameters.min_ccd_dt,
                 contact_damping_ratio: self.integration_parameters.contact_damping_ratio,
                 contact_natural_frequency: self.integration_parameters.contact_natural_frequency,