Fix bugs in text display caused by indices not being normalized.

Fix FPS '.' position
Fix FPS display width.
Fix text spacing in texture frame.

engine/src/fps_counter.cxx

@@ -28,7 +28,7 @@ fps_counter::~fps_counter() {}
 std::string fps_counter::fps(env::clock::duration const & since) const {
   auto fps = magnitude_ * env::clock::duration::period::den / since.count();
   std::string fps_str = std::to_string(fps);
-  fps_str.insert(fps_str.size() - digits_ + 1, ".");
+  fps_str.insert(fps_str.size() - digits_, ".");
   return fps_str;
 }
 
@@ -36,5 +36,5 @@ void fps_counter::set_frame_step(env::clock::duration const & since) {
   if (++counter_ != change_after_) { return; }
   counter_ = 0;
   text_engine_->create_text_cells(
-      glyphs_, {make_vector(5.f, 680.f), make_vector(20.f, 20.f), fps(since)});
+      glyphs_, {make_vector(5.f, 680.f), make_vector(10.f, 20.f), fps(since)});
 }

engine/src/text_engine.cxx

@@ -37,7 +37,12 @@ text_engine::text_engine(std::string const & font,
     : font_(font), prototype_(to_object(font_material(font_), *manager)),
       glyphs_(glyph_locations(font_)) {
   // TODO (sjaffe): Also needs to be programmatic
-  prototype_.frame.size = make_vector(0.125f, 0.125f);
+  auto glyph_size = make_vector(0.125f, 0.125f);
+  // The font I chose is a monospace font where height = 2 * width
+  prototype_.frame.size = glyph_size / make_vector(2, 1);
+  for (auto & pair : glyphs_) {
+    pair.second *= glyph_size;
+  }
 }
 
 void text_engine::create_text_cells(std::vector<graphics::object> & out,