Until there's a faster implementation, just flag-guard selecting unzoomed agents

game/src/lib.rs

@@ -51,6 +51,9 @@ pub fn main() {
     if args.enabled("--lowzoom") {
         opts.min_zoom_for_detail = 1.0;
     }
+    if args.enabled("--select_unzoomed_agents") {
+        opts.select_unzoomed_agents = true;
+    }
 
     if let Some(x) = args.optional("--color_scheme") {
         let mut ok = false;

game/src/options.rs

@@ -29,6 +29,9 @@ pub struct Options {
     pub min_zoom_for_detail: f64,
     /// Draw buildings in different perspectives
     pub camera_angle: CameraAngle,
+    /// Allow selecting agents when unzoomed. Flagged off by default because the implementation is
+    /// too slow.
+    pub select_unzoomed_agents: bool,
 
     /// How much to advance the sim with one of the speed controls
     pub time_increment: Duration,
@@ -54,6 +57,7 @@ impl Options {
             color_scheme: ColorSchemeChoice::Standard,
             min_zoom_for_detail: 4.0,
             camera_angle: CameraAngle::TopDown,
+            select_unzoomed_agents: false,
 
             time_increment: Duration::minutes(10),
             dont_draw_time_warp: false,

game/src/sandbox/mod.rs

@@ -730,6 +730,10 @@ fn mouseover_unzoomed_agent_circle(ctx: &mut EventCtx, app: &mut App) {
     // - We could build and cache a quadtree if we're paused
     // - We could always build the quadtree as we loop over unzoomed agents
     // - At least do this while we draw? Don't call twice.
+    if !app.opts.select_unzoomed_agents {
+        return;
+    }
+
     let cursor = if let Some(pt) = ctx.canvas.get_cursor_in_map_space() {
         pt
     } else {