fix major perf regression from modal menus getting sections. need to

call draw_queued for text once per frame, otherwise cache gets ruined

docs/design/notes/gui.md

@@ -707,3 +707,20 @@ transitions... pop current state, push some new state, replace current state
 I don't want to wind up with the mess of plugins again. Why am I sure it's not that?
 
 - these are complete, mutex states
+
+## Text
+
+What's slow right now?
+- drawing the rectangles?
+- forming the Text?
+- doing the draw_queued flush?
+
+Simpler ideas for speedup:
+= only one draw_queued flush, to preserve caching behavior!
+- batch fork/unfork and all the rectangles? maybe not needed for modal menu
+- detect state changes in ModalMenu, recreate Drawable thing only when needed
+
+Current stack:
+- https://docs.rs/glium-glyph/0.3.0/glium_glyph/
+- https://docs.rs/glyph_brush/0.4.0/glyph_brush/
+- https://docs.rs/rusttype/0.7.7/rusttype/

ezgui/src/event_ctx.rs

@@ -220,6 +220,10 @@ impl<'a> LoadingScreen<'a> {
             &txt,
             (HorizontalAlignment::Center, VerticalAlignment::Center),
         );
+        self.canvas
+            .glyphs
+            .borrow_mut()
+            .draw_queued(self.prerender.display, &mut target);
         target.finish().unwrap();
     }
 }

ezgui/src/runner.rs

@@ -122,6 +122,13 @@ impl<G: GUI> State<G> {
             menu.draw(&mut g);
         }
 
+        // Flush text just once, so that GlyphBrush's internal caching works. We have to assume
+        // nothing will ever cover up text.
+        self.canvas
+            .glyphs
+            .borrow_mut()
+            .draw_queued(display, &mut target);
+
         target.finish().unwrap();
         naming_hint
     }

ezgui/src/text.rs

@@ -239,10 +239,6 @@ pub fn draw_text_bubble(
         y += height;
         g.canvas.glyphs.borrow_mut().queue(section);
     }
-    g.canvas
-        .glyphs
-        .borrow_mut()
-        .draw_queued(g.display, g.target);
 
     g.unfork();