rotate labels on buses, now that i figured out how to do it reasonably on roads

game/src/render/car.rs

@@ -135,13 +135,14 @@ impl DrawCar {
         }
 
         if let Some(line) = input.label {
-            // TODO Would rotation make any sense? Or at least adjust position/size while turning.
             // Buses are a constant length, so hardcoding this is fine.
+            let (pt, angle) = input.body.dist_along(Distance::meters(9.0));
             draw_default.append(
                 Text::from(Line(line).fg(cs.bus_label))
                     .render_to_batch(prerender)
                     .scale(0.07)
-                    .centered_on(input.body.dist_along(Distance::meters(9.0)).0),
+                    .centered_on(pt)
+                    .rotate(angle.reorient()),
             );
         }
 

game/src/render/road.rs

@@ -77,19 +77,12 @@ impl Renderable for DrawRoad {
                         // even easier, just skip the center lines?
                         let txt = Text::from(Line(name).fg(app.cs.road_center_line))
                             .bg(app.cs.driving_lane);
-                        let (pt, mut angle) = r.center_pts.dist_along(r.center_pts.length() / 2.0);
+                        let (pt, angle) = r.center_pts.dist_along(r.center_pts.length() / 2.0);
-                        let theta = angle.normalized_degrees().rem_euclid(360.0);
-                        if theta > 90.0 {
-                            angle = angle.opposite();
-                        }
-                        if theta > 270.0 {
-                            angle = angle.opposite();
-                        }
                         batch.append(
                             txt.render_to_batch(g.prerender)
                                 .scale(0.1)
                                 .centered_on(pt)
-                                .rotate(angle),
+                                .rotate(angle.reorient()),
                         );
                     }
                 }

geom/src/angle.rs

@@ -58,6 +58,17 @@ impl Angle {
             ((self.normalized_degrees() - other.normalized_degrees() + 540.0) % 360.0) - 180.0;
         rotation.abs() < within_degrees
     }
+
+    // I don't know how to describe what this does. Use for rotating labels in map-space and making
+    // sure the text is never upside-down.
+    pub fn reorient(self) -> Angle {
+        let theta = self.normalized_degrees().rem_euclid(360.0);
+        if theta > 90.0 || theta > 270.0 {
+            self.opposite()
+        } else {
+            self
+        }
+    }
 }
 
 impl fmt::Display for Angle {