fix: calculation for rect position scaling in debug_renderer

src/app.rs

@@ -89,7 +89,7 @@ impl App {
             let start = Instant::now();
 
             let dt = self.last_tick.elapsed().as_secs_f32();
-            self.last_tick = Instant::now();
+            self.last_tick = start;
 
             let exit = self.game.tick(dt);
 

src/constants.rs

@@ -8,8 +8,8 @@ use glam::UVec2;
 ///
 /// Calculated as 1/60th of a second (≈16.67ms).
 ///
-/// Written out explicitly to satisfy const-eval constraints.
-pub const LOOP_TIME: Duration = Duration::from_nanos((1_000_000_000.0 / 60.0) as u64);
+/// Uses integer arithmetic to avoid floating-point precision loss.
+pub const LOOP_TIME: Duration = Duration::from_nanos(1_000_000_000 / 60);
 
 /// The size of each cell, in pixels.
 pub const CELL_SIZE: u32 = 8;

src/game.rs

@@ -14,14 +14,16 @@ use crate::systems::components::{GhostAnimation, GhostState, LastAnimationState}
 use crate::systems::movement::{BufferedDirection, Position, Velocity};
 use crate::systems::profiling::SystemId;
 use crate::systems::render::RenderDirty;
-use crate::systems::{self, ghost_collision_system, present_system, Hidden, LinearAnimation, MovementModifiers, NodeId};
 use crate::systems::{
-    audio_system, blinking_system, collision_system, debug_render_system, directional_render_system, dirty_render_system,
-    eaten_ghost_system, ghost_movement_system, ghost_state_system, hud_render_system, item_system, linear_render_system, profile,
-    render_system, AudioEvent, AudioResource, AudioState, BackbufferResource, Collider, DebugFontResource, DebugState,
-    DebugTextureResource, DeltaTime, DirectionalAnimation, EntityType, Frozen, Ghost, GhostAnimations, GhostBundle,
-    GhostCollider, GlobalState, ItemBundle, ItemCollider, MapTextureResource, PacmanCollider, PlayerBundle, PlayerControlled,
-    Renderable, ScoreResource, StartupSequence, SystemTimings,
+    self, combined_render_system, ghost_collision_system, present_system, Hidden, LinearAnimation, MovementModifiers, NodeId,
+};
+use crate::systems::{
+    audio_system, blinking_system, collision_system, directional_render_system, dirty_render_system, eaten_ghost_system,
+    ghost_movement_system, ghost_state_system, hud_render_system, item_system, linear_render_system, profile, AudioEvent,
+    AudioResource, AudioState, BackbufferResource, Collider, DebugState, DebugTextureResource, DeltaTime, DirectionalAnimation,
+    EntityType, Frozen, Ghost, GhostAnimations, GhostBundle, GhostCollider, GlobalState, ItemBundle, ItemCollider,
+    MapTextureResource, PacmanCollider, PlayerBundle, PlayerControlled, Renderable, ScoreResource, StartupSequence,
+    SystemTimings,
 };
 use crate::texture::animated::{DirectionalTiles, TileSequence};
 use crate::texture::sprite::AtlasTile;
@@ -29,8 +31,9 @@ use bevy_ecs::event::EventRegistry;
 use bevy_ecs::observer::Trigger;
 use bevy_ecs::schedule::common_conditions::resource_changed;
 use bevy_ecs::schedule::{Condition, IntoScheduleConfigs, Schedule, SystemSet};
-use bevy_ecs::system::ResMut;
+use bevy_ecs::system::{Local, ResMut};
 use bevy_ecs::world::World;
+use glam::UVec2;
 use sdl2::event::EventType;
 use sdl2::image::LoadTexture;
 use sdl2::render::{BlendMode, Canvas, ScaleMode, TextureCreator};
@@ -42,6 +45,7 @@ use crate::{
     asset::{get_asset_bytes, Asset},
     events::GameCommand,
     map::render::MapRenderer,
+    systems::debug::{BatchedLinesResource, TtfAtlasResource},
     systems::input::{Bindings, CursorPosition},
     texture::sprite::{AtlasMapper, SpriteAtlas},
 };
@@ -125,7 +129,7 @@ impl Game {
             EventType::Display,
             EventType::Window,
             EventType::MouseWheel,
-            EventType::MouseMotion,
+            // EventType::MouseMotion,
             EventType::MouseButtonDown,
             EventType::MouseButtonUp,
             EventType::MouseButtonDown,
@@ -162,12 +166,17 @@ impl Game {
         debug_texture.set_blend_mode(BlendMode::Blend);
         debug_texture.set_scale_mode(ScaleMode::Nearest);
 
+        // Create debug text atlas for efficient debug rendering
         let font_data: &'static [u8] = get_asset_bytes(Asset::Font)?.to_vec().leak();
         let font_asset = RWops::from_bytes(font_data).map_err(|_| GameError::Sdl("Failed to load font".to_string()))?;
         let debug_font = ttf_context
             .load_font_from_rwops(font_asset, constants::ui::DEBUG_FONT_SIZE)
             .map_err(|e| GameError::Sdl(e.to_string()))?;
 
+        let mut ttf_atlas = crate::texture::ttf::TtfAtlas::new(&texture_creator, &debug_font)?;
+        // Populate the atlas with actual character data
+        ttf_atlas.populate_atlas(&mut canvas, &texture_creator, &debug_font)?;
+
         // Initialize audio system
         let audio = crate::audio::Audio::new();
 
@@ -293,6 +302,10 @@ impl Game {
         EventRegistry::register_event::<GameEvent>(&mut world);
         EventRegistry::register_event::<AudioEvent>(&mut world);
 
+        let scale =
+            (UVec2::from(canvas.output_size().unwrap()).as_vec2() / UVec2::from(canvas.logical_size()).as_vec2()).min_element();
+
+        world.insert_resource(BatchedLinesResource::new(&map, scale));
         world.insert_resource(Self::create_ghost_animations(&atlas)?);
         world.insert_resource(map);
         world.insert_resource(GlobalState { exit: false });
@@ -315,7 +328,7 @@ impl Game {
         world.insert_non_send_resource(BackbufferResource(backbuffer));
         world.insert_non_send_resource(MapTextureResource(map_texture));
         world.insert_non_send_resource(DebugTextureResource(debug_texture));
-        world.insert_non_send_resource(DebugFontResource(debug_font));
+        world.insert_non_send_resource(TtfAtlasResource(ttf_atlas));
         world.insert_non_send_resource(AudioResource(audio));
 
         world.add_observer(
@@ -341,9 +354,7 @@ impl Game {
         let directional_render_system = profile(SystemId::DirectionalRender, directional_render_system);
         let linear_render_system = profile(SystemId::LinearRender, linear_render_system);
         let dirty_render_system = profile(SystemId::DirtyRender, dirty_render_system);
-        let render_system = profile(SystemId::Render, render_system);
         let hud_render_system = profile(SystemId::HudRender, hud_render_system);
-        let debug_render_system = profile(SystemId::DebugRender, debug_render_system);
         let present_system = profile(SystemId::Present, present_system);
         let unified_ghost_state_system = profile(SystemId::GhostStateAnimation, ghost_state_system);
 
@@ -354,7 +365,11 @@ impl Game {
         schedule.add_systems((
             forced_dirty_system.run_if(resource_changed::<ScoreResource>.or(resource_changed::<StartupSequence>)),
             (
-                input_system,
+                input_system.run_if(|mut local: Local<u8>| {
+                    *local = local.wrapping_add(1u8);
+                    // run every nth frame
+                    *local % 2 == 0
+                }),
                 player_control_system,
                 player_movement_system,
                 startup_stage_system,
@@ -371,9 +386,8 @@ impl Game {
                 directional_render_system,
                 linear_render_system,
                 dirty_render_system,
-                render_system,
+                combined_render_system,
                 hud_render_system,
-                debug_render_system,
                 present_system,
             )
                 .chain(),

src/systems/debug.rs

@@ -1,17 +1,20 @@
 //! Debug rendering system
 use std::cmp::Ordering;
 
-use crate::constants::BOARD_PIXEL_OFFSET;
+use crate::constants::{BOARD_PIXEL_OFFSET, CANVAS_SIZE};
 use crate::map::builder::Map;
 use crate::systems::{Collider, CursorPosition, NodeId, Position, SystemTimings};
+use crate::texture::ttf::{TtfAtlas, TtfRenderer};
 use bevy_ecs::resource::Resource;
-use bevy_ecs::system::{NonSendMut, Query, Res};
+use bevy_ecs::system::{Query, Res};
 use glam::{IVec2, UVec2, Vec2};
 use sdl2::pixels::Color;
 use sdl2::rect::{Point, Rect};
-use sdl2::render::{Canvas, Texture, TextureCreator};
-use sdl2::ttf::Font;
-use sdl2::video::{Window, WindowContext};
+use sdl2::render::{Canvas, Texture};
+use sdl2::video::Window;
+use smallvec::SmallVec;
+use std::collections::{HashMap, HashSet};
+use tracing::warn;
 
 #[derive(Resource, Default, Debug, Copy, Clone)]
 pub struct DebugState {
@@ -25,31 +28,143 @@ fn f32_to_u8(value: f32) -> u8 {
 /// Resource to hold the debug texture for persistent rendering
 pub struct DebugTextureResource(pub Texture);
 
-/// Resource to hold the debug font
-pub struct DebugFontResource(pub Font<'static, 'static>);
+/// Resource to hold the TTF text atlas
+pub struct TtfAtlasResource(pub TtfAtlas);
+
+/// Resource to hold pre-computed batched line segments
+#[derive(Resource, Default, Debug, Clone)]
+pub struct BatchedLinesResource {
+    horizontal_lines: Vec<(i32, i32, i32)>, // (y, x_start, x_end)
+    vertical_lines: Vec<(i32, i32, i32)>,   // (x, y_start, y_end)
+}
+
+impl BatchedLinesResource {
+    /// Computes and caches batched line segments for the map graph
+    pub fn new(map: &Map, scale: f32) -> Self {
+        let mut horizontal_segments: HashMap<i32, Vec<(i32, i32)>> = HashMap::new();
+        let mut vertical_segments: HashMap<i32, Vec<(i32, i32)>> = HashMap::new();
+        let mut processed_edges: HashSet<(u16, u16)> = HashSet::new();
+
+        // Process all edges and group them by axis
+        for (start_node_id, edge) in map.graph.edges() {
+            // Acquire a stable key for the edge (from < to)
+            let edge_key = (start_node_id.min(edge.target), start_node_id.max(edge.target));
+
+            // Skip if we've already processed this edge in the reverse direction
+            if processed_edges.contains(&edge_key) {
+                continue;
+            }
+            processed_edges.insert(edge_key);
+
+            let start_pos = map.graph.get_node(start_node_id).unwrap().position;
+            let end_pos = map.graph.get_node(edge.target).unwrap().position;
+
+            let start = transform_position_with_offset(start_pos, scale);
+            let end = transform_position_with_offset(end_pos, scale);
+
+            // Determine if this is a horizontal or vertical line
+            if (start.y - end.y).abs() < 2 {
+                // Horizontal line (allowing for slight vertical variance)
+                let y = start.y;
+                let x_min = start.x.min(end.x);
+                let x_max = start.x.max(end.x);
+                horizontal_segments.entry(y).or_default().push((x_min, x_max));
+            } else if (start.x - end.x).abs() < 2 {
+                // Vertical line (allowing for slight horizontal variance)
+                let x = start.x;
+                let y_min = start.y.min(end.y);
+                let y_max = start.y.max(end.y);
+                vertical_segments.entry(x).or_default().push((y_min, y_max));
+            }
+        }
+
+        /// Merges overlapping or adjacent segments into continuous lines
+        fn merge_segments(segments: Vec<(i32, i32)>) -> Vec<(i32, i32)> {
+            if segments.is_empty() {
+                return Vec::new();
+            }
+
+            let mut merged = Vec::new();
+            let mut current_start = segments[0].0;
+            let mut current_end = segments[0].1;
+
+            for &(start, end) in segments.iter().skip(1) {
+                if start <= current_end + 1 {
+                    // Adjacent or overlapping
+                    current_end = current_end.max(end);
+                } else {
+                    merged.push((current_start, current_end));
+                    current_start = start;
+                    current_end = end;
+                }
+            }
+
+            merged.push((current_start, current_end));
+            merged
+        }
+
+        // Convert to flat vectors for fast iteration during rendering
+        let horizontal_lines = horizontal_segments
+            .into_iter()
+            .flat_map(|(y, mut segments)| {
+                segments.sort_unstable_by_key(|(start, _)| *start);
+                let merged = merge_segments(segments);
+                merged.into_iter().map(move |(x_start, x_end)| (y, x_start, x_end))
+            })
+            .collect::<Vec<_>>();
+
+        let vertical_lines = vertical_segments
+            .into_iter()
+            .flat_map(|(x, mut segments)| {
+                segments.sort_unstable_by_key(|(start, _)| *start);
+                let merged = merge_segments(segments);
+                merged.into_iter().map(move |(y_start, y_end)| (x, y_start, y_end))
+            })
+            .collect::<Vec<_>>();
+
+        Self {
+            horizontal_lines,
+            vertical_lines,
+        }
+    }
+
+    pub fn render(&self, canvas: &mut Canvas<Window>) {
+        // Render horizontal lines
+        for &(y, x_start, x_end) in &self.horizontal_lines {
+            let points = [Point::new(x_start, y), Point::new(x_end, y)];
+            let _ = canvas.draw_lines(&points[..]);
+        }
+
+        // Render vertical lines
+        for &(x, y_start, y_end) in &self.vertical_lines {
+            let points = [Point::new(x, y_start), Point::new(x, y_end)];
+            let _ = canvas.draw_lines(&points[..]);
+        }
+    }
+}
 
 /// Transforms a position from logical canvas coordinates to output canvas coordinates (with board offset)
 fn transform_position_with_offset(pos: Vec2, scale: f32) -> IVec2 {
     ((pos + BOARD_PIXEL_OFFSET.as_vec2()) * scale).as_ivec2()
 }
 
-/// Renders timing information in the top-left corner of the screen
+/// Renders timing information in the top-left corner of the screen using the debug text atlas
 fn render_timing_display(
     canvas: &mut Canvas<Window>,
-    texture_creator: &mut TextureCreator<WindowContext>,
     timings: &SystemTimings,
-    font: &Font,
+    text_renderer: &TtfRenderer,
+    atlas: &mut TtfAtlas,
 ) {
     // Format timing information using the formatting module
     let lines = timings.format_timing_display();
-    let line_height = 14; // Approximate line height for 12pt font
+    let line_height = text_renderer.text_height(atlas) as i32 + 2; // Add 2px line spacing
     let padding = 10;
 
     // Calculate background dimensions
     let max_width = lines
         .iter()
         .filter(|l| !l.is_empty()) // Don't consider empty lines for width
-        .map(|line| font.size_of(line).unwrap().0)
+        .map(|line| text_renderer.text_width(atlas, line))
         .max()
         .unwrap_or(0);
 
@@ -75,133 +190,148 @@ fn render_timing_display(
             continue;
         }
 
-        // Render each line
-        let surface = font.render(line).blended(Color::RGBA(255, 255, 255, 200)).unwrap();
-        let texture = texture_creator.create_texture_from_surface(&surface).unwrap();
-
         // Position each line below the previous one
-        let y_pos = padding + (i * line_height) as i32;
-        let dest = Rect::new(padding, y_pos, texture.query().width, texture.query().height);
-        canvas.copy(&texture, None, dest).unwrap();
+        let y_pos = padding + (i as i32 * line_height);
+        let position = Vec2::new(padding as f32, y_pos as f32);
+
+        // Render the line using the debug text renderer
+        text_renderer
+            .render_text(canvas, atlas, line, position, Color::RGBA(255, 255, 255, 200))
+            .unwrap();
     }
 }
 
 #[allow(clippy::too_many_arguments)]
 pub fn debug_render_system(
-    mut canvas: NonSendMut<&mut Canvas<Window>>,
-    mut debug_texture: NonSendMut<DebugTextureResource>,
-    debug_font: NonSendMut<DebugFontResource>,
-    debug_state: Res<DebugState>,
-    timings: Res<SystemTimings>,
-    map: Res<Map>,
-    colliders: Query<(&Collider, &Position)>,
-    cursor: Res<CursorPosition>,
+    canvas: &mut Canvas<Window>,
+    ttf_atlas: &mut TtfAtlasResource,
+    batched_lines: &Res<BatchedLinesResource>,
+    debug_state: &Res<DebugState>,
+    timings: &Res<SystemTimings>,
+    map: &Res<Map>,
+    colliders: &Query<(&Collider, &Position)>,
+    cursor: &Res<CursorPosition>,
 ) {
     if !debug_state.enabled {
         return;
     }
-    let scale =
-        (UVec2::from(canvas.output_size().unwrap()).as_vec2() / UVec2::from(canvas.logical_size()).as_vec2()).min_element();
+    let output = UVec2::from(canvas.output_size().unwrap()).as_vec2();
+    let logical = CANVAS_SIZE.as_vec2();
+    let scale = (output / logical).min_element();
 
-    // Get texture creator before entering the closure to avoid borrowing conflicts
-    let mut texture_creator = canvas.texture_creator();
-    let font = &debug_font.0;
+    // Create debug text renderer
+    let text_renderer = TtfRenderer::new(1.0);
 
-    let cursor_world_pos = match *cursor {
+    let cursor_world_pos = match &**cursor {
         CursorPosition::None => None,
         CursorPosition::Some { position, .. } => Some(position - BOARD_PIXEL_OFFSET.as_vec2()),
     };
 
-    // Draw debug info on the high-resolution debug texture
-    canvas
-        .with_texture_canvas(&mut debug_texture.0, |debug_canvas| {
-            // Clear the debug canvas
-            debug_canvas.set_draw_color(Color::RGBA(0, 0, 0, 0));
-            debug_canvas.clear();
+    // Clear the debug canvas
+    canvas.set_draw_color(Color::RGBA(0, 0, 0, 0));
+    canvas.clear();
 
-            // Find the closest node to the cursor
-            let closest_node = if let Some(cursor_world_pos) = cursor_world_pos {
-                map.graph
-                    .nodes()
-                    .map(|node| node.position.distance(cursor_world_pos))
-                    .enumerate()
-                    .min_by(|(_, a), (_, b)| a.partial_cmp(b).unwrap_or(Ordering::Less))
-                    .map(|(id, _)| id)
-            } else {
-                None
-            };
+    // Find the closest node to the cursor
+    let closest_node = if let Some(cursor_world_pos) = cursor_world_pos {
+        map.graph
+            .nodes()
+            .map(|node| node.position.distance(cursor_world_pos))
+            .enumerate()
+            .min_by(|(_, a), (_, b)| a.partial_cmp(b).unwrap_or(Ordering::Less))
+            .map(|(id, _)| id)
+    } else {
+        None
+    };
 
-            debug_canvas.set_draw_color(Color::GREEN);
-            for (collider, position) in colliders.iter() {
+    canvas.set_draw_color(Color::GREEN);
+    {
+        let rects = colliders
+            .iter()
+            .map(|(collider, position)| {
                 let pos = position.get_pixel_position(&map.graph).unwrap();
 
                 // Transform position and size using common methods
                 let pos = (pos * scale).as_ivec2();
                 let size = (collider.size * scale) as u32;
 
-                let rect = Rect::from_center(Point::from((pos.x, pos.y)), size, size);
-                debug_canvas.draw_rect(rect).unwrap();
-            }
+                Rect::from_center(Point::from((pos.x, pos.y)), size, size)
+            })
+            .collect::<SmallVec<[Rect; 100]>>();
+        if rects.len() > rects.capacity() {
+            warn!(
+                capacity = rects.capacity(),
+                count = rects.len(),
+                "Collider rects capacity exceeded"
+            );
+        }
+        canvas.draw_rects(&rects).unwrap();
+    }
 
-            debug_canvas.set_draw_color(Color {
-                a: f32_to_u8(0.4),
-                ..Color::RED
-            });
-            debug_canvas.set_blend_mode(sdl2::render::BlendMode::Blend);
-            for (start_node, end_node) in map.graph.edges() {
-                let start_node_model = map.graph.get_node(start_node).unwrap();
-                let end_node = map.graph.get_node(end_node.target).unwrap().position;
+    canvas.set_draw_color(Color {
+        a: f32_to_u8(0.6),
+        ..Color::RED
+    });
+    canvas.set_blend_mode(sdl2::render::BlendMode::Blend);
 
-                // Transform positions using common method
-                let start = transform_position_with_offset(start_node_model.position, scale);
-                let end = transform_position_with_offset(end_node, scale);
+    // Use cached batched line segments
+    batched_lines.render(canvas);
 
-                debug_canvas
-                    .draw_line(Point::from((start.x, start.y)), Point::from((end.x, end.y)))
-                    .unwrap();
-            }
-
-            for (id, node) in map.graph.nodes().enumerate() {
-                let pos = node.position;
-
-                // Set color based on whether the node is the closest to the cursor
-                debug_canvas.set_draw_color(Color {
-                    a: f32_to_u8(if Some(id) == closest_node { 0.75 } else { 0.6 }),
-                    ..(if Some(id) == closest_node {
-                        Color::YELLOW
-                    } else {
-                        Color::BLUE
-                    })
-                });
-
-                // Transform position using common method
-                let pos = transform_position_with_offset(pos, scale);
-                let size = (2.0 * scale) as u32;
-
-                debug_canvas
-                    .fill_rect(Rect::new(pos.x - (size as i32 / 2), pos.y - (size as i32 / 2), size, size))
-                    .unwrap();
-            }
-
-            // Render node ID if a node is highlighted
-            if let Some(closest_node_id) = closest_node {
-                let node = map.graph.get_node(closest_node_id as NodeId).unwrap();
+    {
+        let rects: Vec<_> = map
+            .graph
+            .nodes()
+            .enumerate()
+            .filter_map(|(id, node)| {
                 let pos = transform_position_with_offset(node.position, scale);
+                let size = (2.0 * scale) as u32;
+                let rect = Rect::new(pos.x - (size as i32 / 2), pos.y - (size as i32 / 2), size, size);
 
-                let surface = font
-                    .render(&closest_node_id.to_string())
-                    .blended(Color {
-                        a: f32_to_u8(0.4),
-                        ..Color::WHITE
-                    })
-                    .unwrap();
-                let texture = texture_creator.create_texture_from_surface(&surface).unwrap();
-                let dest = Rect::new(pos.x + 10, pos.y - 5, texture.query().width, texture.query().height);
-                debug_canvas.copy(&texture, None, dest).unwrap();
-            }
+                // If the node is the one closest to the cursor, draw it immediately
+                if closest_node == Some(id) {
+                    canvas.set_draw_color(Color::YELLOW);
+                    canvas.fill_rect(rect).unwrap();
+                    return None;
+                }
 
-            // Render timing information in the top-left corner
-            render_timing_display(debug_canvas, &mut texture_creator, &timings, font);
-        })
-        .unwrap();
+                Some(rect)
+            })
+            .collect();
+
+        if rects.len() > rects.capacity() {
+            warn!(
+                capacity = rects.capacity(),
+                count = rects.len(),
+                "Node rects capacity exceeded"
+            );
+        }
+
+        // Draw the non-closest nodes all at once in blue
+        canvas.set_draw_color(Color::BLUE);
+        canvas.fill_rects(&rects).unwrap();
+    }
+
+    // Render node ID if a node is highlighted
+    if let Some(closest_node_id) = closest_node {
+        let node = map.graph.get_node(closest_node_id as NodeId).unwrap();
+        let pos = transform_position_with_offset(node.position, scale);
+
+        let node_id_text = closest_node_id.to_string();
+        let text_pos = Vec2::new((pos.x + 10) as f32, (pos.y - 5) as f32);
+
+        text_renderer
+            .render_text(
+                canvas,
+                &mut ttf_atlas.0,
+                &node_id_text,
+                text_pos,
+                Color {
+                    a: f32_to_u8(0.4),
+                    ..Color::WHITE
+                },
+            )
+            .unwrap();
+    }
+
+    // Render timing information in the top-left corner
+    render_timing_display(canvas, timings, &text_renderer, &mut ttf_atlas.0);
 }

src/systems/input.rs

@@ -138,14 +138,12 @@ pub fn input_system(
 
     // Warn if the smallvec was heap allocated due to exceeding stack capacity
     #[cfg(debug_assertions)]
-    {
-        if frame_events.len() > frame_events.capacity() {
-            tracing::warn!(
-                "More than {} events in a frame, consider adjusting stack capacity: {:?}",
-                frame_events.capacity(),
-                frame_events
-            );
-        }
+    if frame_events.len() > frame_events.capacity() {
+        tracing::warn!(
+            "More than {} events in a frame, consider adjusting stack capacity: {:?}",
+            frame_events.capacity(),
+            frame_events
+        );
     }
 
     // Handle non-keyboard events inline and build a simplified keyboard event stream.

src/systems/profiling.rs

@@ -3,12 +3,12 @@ use bevy_ecs::{resource::Resource, system::System};
 use circular_buffer::CircularBuffer;
 use micromap::Map;
 use num_width::NumberWidth;
-use parking_lot::{Mutex, RwLock};
+use parking_lot::Mutex;
 use smallvec::SmallVec;
 use std::fmt::Display;
 use std::time::Duration;
-use strum::EnumCount;
-use strum_macros::{EnumCount, IntoStaticStr};
+use strum::{EnumCount, IntoEnumIterator};
+use strum_macros::{EnumCount, EnumIter, IntoStaticStr};
 use thousands::Separable;
 
 /// The maximum number of systems that can be profiled. Must not be exceeded, or it will panic.
@@ -16,7 +16,7 @@ const MAX_SYSTEMS: usize = SystemId::COUNT;
 /// The number of durations to keep in the circular buffer.
 const TIMING_WINDOW_SIZE: usize = 30;
 
-#[derive(EnumCount, IntoStaticStr, Debug, PartialEq, Eq, Hash, Copy, Clone)]
+#[derive(EnumCount, EnumIter, IntoStaticStr, Debug, PartialEq, Eq, Hash, Copy, Clone)]
 pub enum SystemId {
     Input,
     PlayerControls,
@@ -46,7 +46,7 @@ impl Display for SystemId {
     }
 }
 
-#[derive(Resource, Default, Debug)]
+#[derive(Resource, Debug)]
 pub struct SystemTimings {
     /// Map of system names to a queue of durations, using a circular buffer.
     ///
@@ -55,52 +55,64 @@ pub struct SystemTimings {
     ///
     /// Also, we use a micromap::Map as the number of systems is generally quite small.
     /// Just make sure to set the capacity appropriately, or it will panic.
-    pub timings: RwLock<Map<SystemId, Mutex<CircularBuffer<TIMING_WINDOW_SIZE, Duration>>, MAX_SYSTEMS>>,
+    ///
+    /// Pre-populated with all SystemId variants during initialization to avoid runtime allocations
+    /// and allow systems to have default zero timings when they don't submit data.
+    pub timings: Map<SystemId, Mutex<CircularBuffer<TIMING_WINDOW_SIZE, Duration>>, MAX_SYSTEMS>,
+}
+
+impl Default for SystemTimings {
+    fn default() -> Self {
+        let mut timings = Map::new();
+
+        // Pre-populate with all SystemId variants to avoid runtime allocations
+        // and provide default zero timings for systems that don't submit data
+        for id in SystemId::iter() {
+            timings.insert(id, Mutex::new(CircularBuffer::new()));
+        }
+
+        Self { timings }
+    }
 }
 
 impl SystemTimings {
     pub fn add_timing(&self, id: SystemId, duration: Duration) {
-        // acquire a upgradable read lock
-        let mut timings = self.timings.upgradable_read();
-
-        // happy path, the name is already in the map (no need to mutate the hashmap)
-        if timings.contains_key(&id) {
-            let queue = timings
-                .get(&id)
-                .expect("System name not found in map after contains_key check");
-            let mut queue = queue.lock();
-
-            queue.push_back(duration);
-            return;
-        }
-
-        // otherwise, acquire a write lock and insert a new queue
-        timings.with_upgraded(|timings| {
-            let queue = timings.entry(id).or_insert_with(|| Mutex::new(CircularBuffer::new()));
-            queue.lock().push_back(duration);
-        });
+        // Since all SystemId variants are pre-populated, we can use a simple read lock
+        let queue = self
+            .timings
+            .get(&id)
+            .expect("SystemId not found in pre-populated map - this is a bug");
+        queue.lock().push_back(duration);
     }
 
     pub fn get_stats(&self) -> Map<SystemId, (Duration, Duration), MAX_SYSTEMS> {
-        let timings = self.timings.read();
         let mut stats = Map::new();
 
-        for (id, queue) in timings.iter() {
-            if queue.lock().is_empty() {
+        // Iterate over all SystemId variants to ensure every system has an entry
+        for id in SystemId::iter() {
+            let queue = self
+                .timings
+                .get(&id)
+                .expect("SystemId not found in pre-populated map - this is a bug");
+
+            let queue_guard = queue.lock();
+            if queue_guard.is_empty() {
+                // Return zero timing for systems that haven't submitted any data
+                stats.insert(id, (Duration::ZERO, Duration::ZERO));
                 continue;
             }
 
-            let durations: Vec<f64> = queue.lock().iter().map(|d| d.as_secs_f64() * 1000.0).collect();
+            let durations: Vec<f64> = queue_guard.iter().map(|d| d.as_secs_f64() * 1000.0).collect();
             let count = durations.len() as f64;
 
             let sum: f64 = durations.iter().sum();
             let mean = sum / count;
 
-            let variance = durations.iter().map(|x| (x - mean).powi(2)).sum::<f64>() / count;
+            let variance = durations.iter().map(|x| (x - mean).powi(2)).sum::<f64>() / (count - 1.0).max(1.0);
             let std_dev = variance.sqrt();
 
             stats.insert(
-                *id,
+                id,
                 (
                     Duration::from_secs_f64(mean / 1000.0),
                     Duration::from_secs_f64(std_dev / 1000.0),
@@ -113,8 +125,7 @@ impl SystemTimings {
 
     pub fn get_total_stats(&self) -> (Duration, Duration) {
         let duration_sums = {
-            let timings = self.timings.read();
-            timings
+            self.timings
                 .iter()
                 .map(|(_, queue)| queue.lock().iter().sum::<Duration>())
                 .collect::<Vec<_>>()
@@ -128,7 +139,7 @@ impl SystemTimings {
                 diff_secs * diff_secs
             })
             .sum::<f64>()
-            / duration_sums.len() as f64;
+            / (duration_sums.len() - 1).max(1) as f64;
         let std_dev_secs = variance.sqrt();
 
         (mean, Duration::from_secs_f64(std_dev_secs))
@@ -250,17 +261,22 @@ pub fn format_timing_display(
         })
         .collect::<SmallVec<[Entry; 12]>>();
 
-    let (max_name_width, max_avg_int_width, max_avg_decimal_width, max_std_int_width, max_std_decimal_width) = entries
-        .iter()
-        .fold((0, 0, 3, 0, 3), |(name_w, avg_int_w, avg_dec_w, std_int_w, std_dec_w), e| {
-            (
-                name_w.max(e.name.len()),
-                avg_int_w.max(e.avg_int.width() as usize),
-                avg_dec_w.max(e.avg_decimal.width() as usize),
-                std_int_w.max(e.std_int.width() as usize),
-                std_dec_w.max(e.std_decimal.width() as usize),
-            )
-        });
+    let (max_avg_int_width, max_avg_decimal_width, max_std_int_width, max_std_decimal_width) =
+        entries
+            .iter()
+            .fold((0, 3, 0, 3), |(avg_int_w, avg_dec_w, std_int_w, std_dec_w), e| {
+                (
+                    avg_int_w.max(e.avg_int.width() as usize),
+                    avg_dec_w.max(e.avg_decimal.width() as usize),
+                    std_int_w.max(e.std_int.width() as usize),
+                    std_dec_w.max(e.std_decimal.width() as usize),
+                )
+            });
+
+    let max_name_width = SystemId::iter()
+        .map(|id| id.to_string().len())
+        .max()
+        .expect("SystemId::iter() returned an empty iterator");
 
     entries.iter().map(|e| {
             format!(

src/systems/render.rs

@@ -2,8 +2,9 @@ use crate::constants::CANVAS_SIZE;
 use crate::error::{GameError, TextureError};
 use crate::map::builder::Map;
 use crate::systems::{
-    DebugState, DebugTextureResource, DeltaTime, DirectionalAnimation, LinearAnimation, Position, Renderable, ScoreResource,
-    StartupSequence, Velocity,
+    debug_render_system, BatchedLinesResource, Collider, CursorPosition, DebugState, DebugTextureResource, DeltaTime,
+    DirectionalAnimation, LinearAnimation, Position, Renderable, ScoreResource, StartupSequence, SystemId, SystemTimings,
+    TtfAtlasResource, Velocity,
 };
 use crate::texture::sprite::SpriteAtlas;
 use crate::texture::text::TextTexture;
@@ -18,6 +19,7 @@ use sdl2::pixels::Color;
 use sdl2::rect::{Point, Rect};
 use sdl2::render::{BlendMode, Canvas, Texture};
 use sdl2::video::Window;
+use std::time::Instant;
 
 #[derive(Resource, Default)]
 pub struct RenderDirty(pub bool);
@@ -25,6 +27,13 @@ pub struct RenderDirty(pub bool);
 #[derive(Component)]
 pub struct Hidden;
 
+/// Enum to identify which texture is being rendered to in the combined render system
+#[derive(Debug, Clone, Copy)]
+enum RenderTarget {
+    Backbuffer,
+    Debug,
+}
+
 #[allow(clippy::type_complexity)]
 pub fn dirty_render_system(
     mut dirty: ResMut<RenderDirty>,
@@ -172,59 +181,138 @@ pub fn hud_render_system(
 
 #[allow(clippy::too_many_arguments)]
 pub fn render_system(
+    canvas: &mut Canvas<Window>,
+    map_texture: &NonSendMut<MapTextureResource>,
+    atlas: &mut SpriteAtlas,
+    map: &Res<Map>,
+    dirty: &Res<RenderDirty>,
+    renderables: &Query<(Entity, &Renderable, &Position), Without<Hidden>>,
+    errors: &mut EventWriter<GameError>,
+) {
+    if !dirty.0 {
+        return;
+    }
+
+    // Clear the backbuffer
+    canvas.set_draw_color(sdl2::pixels::Color::BLACK);
+    canvas.clear();
+
+    // Copy the pre-rendered map texture to the backbuffer
+    if let Err(e) = canvas.copy(&map_texture.0, None, None) {
+        errors.write(TextureError::RenderFailed(e.to_string()).into());
+    }
+
+    // Render all entities to the backbuffer
+    for (_, renderable, position) in renderables
+        .iter()
+        .sort_by_key::<(Entity, &Renderable, &Position), _>(|(_, renderable, _)| renderable.layer)
+        .rev()
+    {
+        let pos = position.get_pixel_position(&map.graph);
+        match pos {
+            Ok(pos) => {
+                let dest = Rect::from_center(
+                    Point::from((pos.x as i32, pos.y as i32)),
+                    renderable.sprite.size.x as u32,
+                    renderable.sprite.size.y as u32,
+                );
+
+                renderable
+                    .sprite
+                    .render(canvas, atlas, dest)
+                    .err()
+                    .map(|e| errors.write(TextureError::RenderFailed(e.to_string()).into()));
+            }
+            Err(e) => {
+                errors.write(e);
+            }
+        }
+    }
+}
+
+/// Combined render system that renders to both backbuffer and debug textures in a single
+/// with_multiple_texture_canvas call for reduced overhead
+#[allow(clippy::too_many_arguments)]
+pub fn combined_render_system(
     mut canvas: NonSendMut<&mut Canvas<Window>>,
     map_texture: NonSendMut<MapTextureResource>,
     mut backbuffer: NonSendMut<BackbufferResource>,
+    mut debug_texture: NonSendMut<DebugTextureResource>,
     mut atlas: NonSendMut<SpriteAtlas>,
+    mut ttf_atlas: NonSendMut<TtfAtlasResource>,
+    batched_lines: Res<BatchedLinesResource>,
+    debug_state: Res<DebugState>,
+    timings: Res<SystemTimings>,
     map: Res<Map>,
     dirty: Res<RenderDirty>,
     renderables: Query<(Entity, &Renderable, &Position), Without<Hidden>>,
+    colliders: Query<(&Collider, &Position)>,
+    cursor: Res<CursorPosition>,
     mut errors: EventWriter<GameError>,
 ) {
     if !dirty.0 {
         return;
     }
-    // Render to backbuffer
-    canvas
-        .with_texture_canvas(&mut backbuffer.0, |backbuffer_canvas| {
-            // Clear the backbuffer
-            backbuffer_canvas.set_draw_color(sdl2::pixels::Color::BLACK);
-            backbuffer_canvas.clear();
 
-            // Copy the pre-rendered map texture to the backbuffer
-            if let Err(e) = backbuffer_canvas.copy(&map_texture.0, None, None) {
-                errors.write(TextureError::RenderFailed(e.to_string()).into());
+    // Prepare textures and render targets
+    let textures = [
+        (&mut backbuffer.0, RenderTarget::Backbuffer),
+        (&mut debug_texture.0, RenderTarget::Debug),
+    ];
+
+    // Record timing for each system independently
+    let mut render_duration = None;
+    let mut debug_render_duration = None;
+
+    let result = canvas.with_multiple_texture_canvas(textures.iter(), |texture_canvas, render_target| match render_target {
+        RenderTarget::Backbuffer => {
+            let start_time = Instant::now();
+
+            render_system(
+                texture_canvas,
+                &map_texture,
+                &mut atlas,
+                &map,
+                &dirty,
+                &renderables,
+                &mut errors,
+            );
+
+            render_duration = Some(start_time.elapsed());
+        }
+        RenderTarget::Debug => {
+            if !debug_state.enabled {
+                return;
             }
 
-            // Render all entities to the backbuffer
-            for (_, renderable, position) in renderables
-                .iter()
-                .sort_by_key::<(Entity, &Renderable, &Position), _>(|(_, renderable, _)| renderable.layer)
-                .rev()
-            {
-                let pos = position.get_pixel_position(&map.graph);
-                match pos {
-                    Ok(pos) => {
-                        let dest = Rect::from_center(
-                            Point::from((pos.x as i32, pos.y as i32)),
-                            renderable.sprite.size.x as u32,
-                            renderable.sprite.size.y as u32,
-                        );
+            let start_time = Instant::now();
 
-                        renderable
-                            .sprite
-                            .render(backbuffer_canvas, &mut atlas, dest)
-                            .err()
-                            .map(|e| errors.write(TextureError::RenderFailed(e.to_string()).into()));
-                    }
-                    Err(e) => {
-                        errors.write(e);
-                    }
-                }
-            }
-        })
-        .err()
-        .map(|e| errors.write(TextureError::RenderFailed(e.to_string()).into()));
+            debug_render_system(
+                texture_canvas,
+                &mut ttf_atlas,
+                &batched_lines,
+                &debug_state,
+                &timings,
+                &map,
+                &colliders,
+                &cursor,
+            );
+
+            debug_render_duration = Some(start_time.elapsed());
+        }
+    });
+
+    if let Err(e) = result {
+        errors.write(TextureError::RenderFailed(e.to_string()).into());
+    }
+
+    // Record timings for each system independently
+    if let Some(duration) = render_duration {
+        timings.add_timing(SystemId::Render, duration);
+    }
+    if let Some(duration) = debug_render_duration {
+        timings.add_timing(SystemId::DebugRender, duration);
+    }
 }
 
 pub fn present_system(

src/texture/mod.rs

@@ -2,3 +2,4 @@ pub mod animated;
 pub mod blinking;
 pub mod sprite;
 pub mod text;
+pub mod ttf;

src/texture/ttf.rs

@@ -0,0 +1,272 @@
+//! TTF font rendering using pre-rendered character atlas.
+//!
+//! This module provides efficient TTF font rendering by pre-rendering all needed
+//! characters into a texture atlas at startup, avoiding expensive SDL2 font
+//! surface-to-texture conversions every frame.
+
+use glam::{UVec2, Vec2};
+use sdl2::pixels::Color;
+use sdl2::rect::Rect;
+use sdl2::render::{Canvas, RenderTarget, Texture, TextureCreator};
+
+use sdl2::ttf::Font;
+use sdl2::video::WindowContext;
+use std::collections::HashMap;
+
+use crate::error::{GameError, TextureError};
+
+/// Character atlas tile representing a single rendered character
+#[derive(Clone, Copy, Debug)]
+pub struct TtfCharTile {
+    pub pos: UVec2,
+    pub size: UVec2,
+    pub advance: u32, // Character advance width for proportional fonts
+}
+
+/// TTF text atlas containing pre-rendered characters for efficient rendering
+pub struct TtfAtlas {
+    /// The texture containing all rendered characters
+    texture: Texture,
+    /// Mapping from character to its position and size in the atlas
+    char_tiles: HashMap<char, TtfCharTile>,
+    /// Cached color modulation state to avoid redundant SDL2 calls
+    last_modulation: Option<Color>,
+}
+
+const TTF_CHARS: &str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz.,:-/()ms μµ%± ";
+
+impl TtfAtlas {
+    /// Creates a new TTF text atlas by pre-rendering all needed characters.
+    ///
+    /// This should be called once at startup. It renders all characters that might
+    /// be used in text rendering into a single texture atlas for efficient GPU rendering.
+    pub fn new(texture_creator: &TextureCreator<WindowContext>, font: &Font) -> Result<Self, GameError> {
+        // Calculate character dimensions and advance widths for proportional fonts
+        let mut char_tiles = HashMap::new();
+        let mut max_height = 0u32;
+        let mut total_width = 0u32;
+        let mut char_metrics = Vec::new();
+
+        // First pass: measure all characters
+        for c in TTF_CHARS.chars() {
+            if c == ' ' {
+                // Handle space character specially - measure a non-space character for height
+                let space_height = font.size_of("0").map_err(|e| GameError::Sdl(e.to_string()))?.1;
+                let space_advance = font.size_of(" ").map_err(|e| GameError::Sdl(e.to_string()))?.0;
+                char_tiles.insert(
+                    c,
+                    TtfCharTile {
+                        pos: UVec2::ZERO,                  // Will be set during population
+                        size: UVec2::new(0, space_height), // Space has no visual content
+                        advance: space_advance,
+                    },
+                );
+                max_height = max_height.max(space_height);
+                char_metrics.push((c, 0, space_height, space_advance));
+            } else {
+                let (advance, height) = font.size_of(&c.to_string()).map_err(|e| GameError::Sdl(e.to_string()))?;
+                char_tiles.insert(
+                    c,
+                    TtfCharTile {
+                        pos: UVec2::ZERO, // Will be set during population
+                        size: UVec2::new(advance, height),
+                        advance,
+                    },
+                );
+                max_height = max_height.max(height);
+                total_width += advance;
+                char_metrics.push((c, advance, height, advance));
+            }
+        }
+
+        // Calculate atlas dimensions (pack characters horizontally for better space utilization)
+        let atlas_size = UVec2::new(total_width, max_height);
+
+        // Create atlas texture as a render target
+        let mut atlas_texture = texture_creator
+            .create_texture_target(None, atlas_size.x, atlas_size.y)
+            .map_err(|e| GameError::Sdl(e.to_string()))?;
+        atlas_texture.set_blend_mode(sdl2::render::BlendMode::Blend);
+
+        // Second pass: calculate positions
+        let mut current_x = 0u32;
+        for (c, width, _height, _advance) in char_metrics {
+            if let Some(tile) = char_tiles.get_mut(&c) {
+                tile.pos = UVec2::new(current_x, 0);
+                current_x += width;
+            }
+        }
+
+        Ok(Self {
+            texture: atlas_texture,
+            char_tiles,
+            last_modulation: None,
+        })
+    }
+
+    /// Renders all characters to the atlas texture using a canvas.
+    /// This must be called after creation to populate the atlas.
+    pub fn populate_atlas<C: RenderTarget>(
+        &mut self,
+        canvas: &mut Canvas<C>,
+        texture_creator: &TextureCreator<WindowContext>,
+        font: &Font,
+    ) -> Result<(), GameError> {
+        let mut render_error: Option<GameError> = None;
+
+        let result = canvas.with_texture_canvas(&mut self.texture, |atlas_canvas| {
+            // Clear with transparent background
+            atlas_canvas.set_draw_color(Color::RGBA(0, 0, 0, 0));
+            atlas_canvas.clear();
+
+            for c in TTF_CHARS.chars() {
+                if c == ' ' {
+                    // Skip rendering space character - it has no visual content
+                    continue;
+                }
+
+                // Render character to surface
+                let surface = match font.render(&c.to_string()).blended(Color::WHITE) {
+                    Ok(s) => s,
+                    Err(e) => {
+                        render_error = Some(GameError::Sdl(e.to_string()));
+                        return;
+                    }
+                };
+
+                // Create texture from surface
+                let char_texture = match texture_creator.create_texture_from_surface(&surface) {
+                    Ok(t) => t,
+                    Err(e) => {
+                        render_error = Some(GameError::Sdl(e.to_string()));
+                        return;
+                    }
+                };
+
+                // Get character tile info
+                let tile = match self.char_tiles.get(&c) {
+                    Some(t) => t,
+                    None => {
+                        render_error = Some(GameError::Sdl(format!("Character '{}' not found in atlas tiles", c)));
+                        return;
+                    }
+                };
+
+                // Copy character to atlas
+                let dest = Rect::new(tile.pos.x as i32, tile.pos.y as i32, tile.size.x, tile.size.y);
+                if let Err(e) = atlas_canvas.copy(&char_texture, None, dest) {
+                    render_error = Some(GameError::Sdl(e.to_string()));
+                    return;
+                }
+            }
+        });
+
+        // Check the result of with_texture_canvas and any render error
+        if let Err(e) = result {
+            return Err(GameError::Sdl(e.to_string()));
+        }
+
+        if let Some(error) = render_error {
+            return Err(error);
+        }
+
+        Ok(())
+    }
+
+    /// Gets a character tile from the atlas
+    pub fn get_char_tile(&self, c: char) -> Option<&TtfCharTile> {
+        self.char_tiles.get(&c)
+    }
+}
+
+/// TTF text renderer that uses the pre-rendered character atlas
+pub struct TtfRenderer {
+    scale: f32,
+}
+
+impl TtfRenderer {
+    pub fn new(scale: f32) -> Self {
+        Self { scale }
+    }
+
+    /// Renders a string of text at the given position with the specified color
+    pub fn render_text<C: RenderTarget>(
+        &self,
+        canvas: &mut Canvas<C>,
+        atlas: &mut TtfAtlas,
+        text: &str,
+        position: Vec2,
+        color: Color,
+    ) -> Result<(), TextureError> {
+        let mut x_offset = 0.0;
+
+        // Apply color modulation once at the beginning if needed
+        if atlas.last_modulation != Some(color) {
+            atlas.texture.set_color_mod(color.r, color.g, color.b);
+            atlas.texture.set_alpha_mod(color.a);
+            atlas.last_modulation = Some(color);
+        }
+
+        for c in text.chars() {
+            // Get character tile info first to avoid borrowing conflicts
+            let char_tile = atlas.get_char_tile(c);
+
+            if let Some(char_tile) = char_tile {
+                if char_tile.size.x > 0 && char_tile.size.y > 0 {
+                    // Only render non-space characters
+                    let dest = Rect::new(
+                        (position.x + x_offset) as i32,
+                        position.y as i32,
+                        (char_tile.size.x as f32 * self.scale) as u32,
+                        (char_tile.size.y as f32 * self.scale) as u32,
+                    );
+
+                    // Render the character directly
+                    let src = Rect::new(
+                        char_tile.pos.x as i32,
+                        char_tile.pos.y as i32,
+                        char_tile.size.x,
+                        char_tile.size.y,
+                    );
+                    canvas.copy(&atlas.texture, src, dest).map_err(TextureError::RenderFailed)?;
+                }
+
+                // Advance by character advance width (proportional spacing)
+                x_offset += char_tile.advance as f32 * self.scale;
+            } else {
+                // Fallback for unsupported characters - use a reasonable default
+                x_offset += 8.0 * self.scale;
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Calculate the width of a text string in pixels
+    pub fn text_width(&self, atlas: &TtfAtlas, text: &str) -> u32 {
+        let mut total_width = 0u32;
+
+        for c in text.chars() {
+            if let Some(char_tile) = atlas.get_char_tile(c) {
+                total_width += (char_tile.advance as f32 * self.scale) as u32;
+            } else {
+                // Fallback for unsupported characters
+                total_width += (8.0 * self.scale) as u32;
+            }
+        }
+
+        total_width
+    }
+
+    /// Calculate the height of text in pixels
+    pub fn text_height(&self, atlas: &TtfAtlas) -> u32 {
+        // Find the maximum height among all characters
+        atlas
+            .char_tiles
+            .values()
+            .map(|tile| tile.size.y)
+            .max()
+            .unwrap_or(0)
+            .saturating_mul(self.scale as u32)
+    }
+}

tests/profiling.rs

@@ -1,5 +1,22 @@
 use pacman::systems::profiling::{SystemId, SystemTimings};
 use std::time::Duration;
+use strum::IntoEnumIterator;
+
+macro_rules! assert_close {
+    ($actual:expr, $expected:expr, $concern:expr) => {
+        let tolerance = Duration::from_micros(500);
+        let diff = $actual.abs_diff($expected);
+        assert!(
+            diff < tolerance,
+            "Expected {expected:?} ± {tolerance:.0?}, got {actual:?}, off by {diff:?} ({concern})",
+            concern = $concern,
+            expected = $expected,
+            actual = $actual,
+            tolerance = tolerance,
+            diff = diff
+        );
+    };
+}
 
 #[test]
 fn test_timing_statistics() {
@@ -14,47 +31,80 @@ fn test_timing_statistics() {
     timings.add_timing(SystemId::Blinking, Duration::from_millis(3));
     timings.add_timing(SystemId::Blinking, Duration::from_millis(2));
     timings.add_timing(SystemId::Blinking, Duration::from_millis(1));
-    fn close_enough(a: Duration, b: Duration) -> bool {
-        if a > b {
-            a - b < Duration::from_micros(500) // 0.1ms
-        } else {
-            b - a < Duration::from_micros(500)
-        }
+
+    {
+        let stats = timings.get_stats();
+        let (avg, std_dev) = stats.get(&SystemId::PlayerControls).unwrap();
+
+        assert_close!(*avg, Duration::from_millis(10), "PlayerControls average timing");
+        assert_close!(*std_dev, Duration::from_millis(2), "PlayerControls standard deviation timing");
     }
 
-    let stats = timings.get_stats();
-    let (avg, std_dev) = stats.get(&SystemId::PlayerControls).unwrap();
-
-    // Average should be 10ms, standard deviation should be small
-    assert!(close_enough(*avg, Duration::from_millis(10)), "avg: {:?}", avg);
-    assert!(close_enough(*std_dev, Duration::from_millis(2)), "std_dev: {:?}", std_dev);
-
-    let (total_avg, total_std) = timings.get_total_stats();
-    assert!(
-        close_enough(total_avg, Duration::from_millis(18)),
-        "total_avg: {:?}",
-        total_avg
-    );
-    assert!(
-        close_enough(total_std, Duration::from_millis(12)),
-        "total_std: {:?}",
-        total_std
-    );
+    {
+        let (total_avg, total_std) = timings.get_total_stats();
+        assert_close!(total_avg, Duration::from_millis(2), "Total average timing across all systems");
+        assert_close!(
+            total_std,
+            Duration::from_millis(7),
+            "Total standard deviation timing across all systems"
+        );
+    }
 }
 
-// #[test]
-// fn test_window_size_limit() {
-//     let timings = SystemTimings::default();
+#[test]
+fn test_default_zero_timing_for_unused_systems() {
+    let timings = SystemTimings::default();
 
-//     // Add more than 90 timings to test window size limit
-//     for i in 0..100 {
-//         timings.add_timing("test_system", Duration::from_millis(i));
-//     }
+    // Add timing data for only one system
+    timings.add_timing(SystemId::PlayerControls, Duration::from_millis(5));
 
-//     let stats = timings.get_stats();
-//     let (avg, _) = stats.get("test_system").unwrap();
+    let stats = timings.get_stats();
 
-//     // Should only keep the last 90 values, so average should be around 55ms
-//     // (average of 10-99)
-//     assert!((avg.as_millis() as f64 - 55.0).abs() < 5.0);
-// }
+    // Verify all SystemId variants are present in the stats
+    let expected_count = SystemId::iter().count();
+    assert_eq!(stats.len(), expected_count, "All SystemId variants should be in stats");
+
+    // Verify that the system with data has non-zero timing
+    let (avg, std_dev) = stats.get(&SystemId::PlayerControls).unwrap();
+    assert_close!(*avg, Duration::from_millis(5), "System with data should have correct timing");
+    assert_close!(*std_dev, Duration::ZERO, "Single measurement should have zero std dev");
+
+    // Verify that all other systems have zero timing
+    for id in SystemId::iter() {
+        if id != SystemId::PlayerControls {
+            let (avg, std_dev) = stats.get(&id).unwrap();
+            assert_close!(
+                *avg,
+                Duration::ZERO,
+                format!("Unused system {:?} should have zero avg timing", id)
+            );
+            assert_close!(
+                *std_dev,
+                Duration::ZERO,
+                format!("Unused system {:?} should have zero std dev", id)
+            );
+        }
+    }
+}
+
+#[test]
+fn test_pre_populated_timing_entries() {
+    let timings = SystemTimings::default();
+
+    // Verify that we can add timing to any SystemId without panicking
+    // (this would fail with the old implementation if the entry didn't exist)
+    for id in SystemId::iter() {
+        timings.add_timing(id, Duration::from_nanos(1));
+    }
+
+    // Verify all systems now have non-zero timing
+    let stats = timings.get_stats();
+    for id in SystemId::iter() {
+        let (avg, _) = stats.get(&id).unwrap();
+        assert!(
+            *avg > Duration::ZERO,
+            "System {:?} should have non-zero timing after add_timing",
+            id
+        );
+    }
+}