start tutorial with sim playing

editor/src/plugins/sim/controls.rs

@@ -31,6 +31,14 @@ impl SimControls {
             primary_events: None,
         }
     }
+
+    pub fn run_sim(&mut self, primary_sim: &mut Sim) {
+        self.state = State::Running {
+            last_step: Instant::now(),
+            benchmark: primary_sim.start_benchmark(),
+            speed: "running".to_string(),
+        };
+    }
 }
 
 impl Plugin for SimControls {
@@ -118,11 +126,7 @@ impl Plugin for SimControls {
                 }
 
                 if ctx.input.action_chosen("run/pause sim") {
-                    self.state = State::Running {
+                    self.run_sim(&mut ctx.primary.sim);
-                        last_step: Instant::now(),
-                        benchmark: ctx.primary.sim.start_benchmark(),
-                        speed: "running".to_string(),
-                    };
                 } else if ctx.input.action_chosen("run one step of sim") {
                     let tick = ctx.primary.sim.time;
                     let events = ctx.primary.sim.step(&ctx.primary.map);

editor/src/plugins/sim/mod.rs

@@ -6,7 +6,7 @@ mod show_score;
 use crate::objects::Ctx;
 use crate::plugins::{Plugin, PluginCtx};
 use ezgui::GfxCtx;
-use sim::{Event, Tick};
+use sim::{Event, Sim, Tick};
 
 // TODO This is per UI, so it's never reloaded. Make sure to detect new loads, even when the
 // initial time is 0? But we probably have no state then, so...
@@ -44,6 +44,13 @@ impl SimMode {
             None
         }
     }
+
+    pub fn run_sim(&mut self, primary_sim: &mut Sim) {
+        self.ambient_plugins[1]
+            .downcast_mut::<controls::SimControls>()
+            .unwrap()
+            .run_sim(primary_sim);
+    }
 }
 
 impl Plugin for SimMode {

editor/src/tutorial.rs

@@ -62,6 +62,9 @@ impl UIState for TutorialState {
             State::GiveInstructions(ref mut scroller) => {
                 if scroller.event(input) {
                     setup_scenario(&mut self.main.primary);
+                    // TODO Levels of indirection now feel bad. I almost want dependency injection
+                    // -- just give me the SimControls.
+                    self.main.sim_mode.run_sim(&mut self.main.primary.sim);
                     self.state = State::Play {
                         last_tick_observed: None,
                         spawned_from_north: 0,