fix

backend/src/game.rs

@@ -71,7 +71,6 @@ impl Game {
         broom_y: f32,
         velocity: f32,
         curl: i8,
-        friction: f32,
     ) -> Result<Vec<StonePath>, String> {
         if self.turn_team != team {
             return Err("Not your turn".to_string());
@@ -81,9 +80,9 @@ impl Game {
         }
 
         self.active_stones.clear();
-        let trajectory =
+        let trajectory = self
-            self.physics
+            .physics
-                .throw(self.turn_team, broom_x, broom_y, velocity, curl, friction)?;
+            .throw(self.turn_team, broom_x, broom_y, velocity, curl)?;
         self.active_stones = self.physics.current_stones();
         self.phase = GamePhase::Simulating;
 
@@ -102,9 +101,8 @@ impl Game {
         broom_y: f32,
         velocity: f32,
         curl: i8,
-        friction: f32,
     ) -> Result<ThrowOutcome, String> {
-        let trajectories = self.handle_throw(team, broom_x, broom_y, velocity, curl, friction)?;
+        let trajectories = self.handle_throw(team, broom_x, broom_y, velocity, curl)?;
         self.finish_simulation();
 
         let state_message = self.game_state_message();
@@ -259,7 +257,7 @@ impl Room {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::physics::DRAW_VELOCITY;
+    use crate::protocol::DRAW_VELOCITY;
 
     #[test]
     fn starts_in_waiting_phase() {
@@ -285,7 +283,7 @@ mod tests {
         game.start();
         let turn = game.turn_team;
         let wrong = turn.other();
-        let result = game.handle_throw(wrong, 0.5, 38.7, DRAW_VELOCITY, 1, 1.0);
+        let result = game.handle_throw(wrong, 0.5, 38.7, DRAW_VELOCITY, 1);
         assert!(result.is_err());
     }
 
@@ -294,7 +292,7 @@ mod tests {
         let mut game = Game::new();
         game.start();
         let turn = game.turn_team;
-        let result = game.handle_throw(turn, 0.5, 38.7, DRAW_VELOCITY, 1, 1.0);
+        let result = game.handle_throw(turn, 0.5, 38.7, DRAW_VELOCITY, 1);
         assert!(result.is_ok());
         let paths = result.unwrap();
         assert!(!paths.is_empty());
@@ -308,7 +306,7 @@ mod tests {
         game.start();
         let turn = game.turn_team;
         // (0.0, 30.0) is well outside HOUSE_RADIUS of HOUSE_CENTER
-        let result = game.handle_throw(turn, 0.0, 30.0, DRAW_VELOCITY, 1, 1.0);
+        let result = game.handle_throw(turn, 0.0, 30.0, DRAW_VELOCITY, 1);
         assert!(
             result.is_ok(),
             "broom outside house should be allowed: {:?}",
@@ -322,7 +320,7 @@ mod tests {
         game.start();
         let turn = game.turn_team;
         let outcome = game
-            .process_throw(turn, 0.0, HOUSE_CENTER.1, DRAW_VELOCITY, 0, 1.0)
+            .process_throw(turn, 0.0, HOUSE_CENTER.1, DRAW_VELOCITY, 0)
             .unwrap();
         // ThrowOutcome must not carry end_scored
         assert!(!outcome.trajectories.is_empty());
@@ -366,7 +364,7 @@ mod tests {
         let mut game = Game::new();
         game.start();
         let turn = game.turn_team;
-        game.handle_throw(turn, 0.0, HOUSE_CENTER.1, DRAW_VELOCITY, 0, 1.0)
+        game.handle_throw(turn, 0.0, HOUSE_CENTER.1, DRAW_VELOCITY, 0)
             .unwrap();
         match turn {
             Team::Team1 => assert_eq!(game.stones_team1, STONES_PER_TEAM - 1),

backend/src/main.rs

@@ -180,12 +180,11 @@ fn spawn_message_handler(
                     broom_y,
                     velocity,
                     curl,
-                    friction,
                 }) => {
                     let mut room_guard = room.lock().await;
                     match room_guard
                         .game
-                        .process_throw(team, broom_x, broom_y, velocity, curl, friction)
+                        .process_throw(team, broom_x, broom_y, velocity, curl)
                     {
                         Ok(ThrowOutcome {
                             trajectories,

backend/src/protocol.rs

@@ -17,26 +17,45 @@ pub const SHEET_LENGTH: f32 = 45.0;
 pub const HOUSE_CENTER: (f32, f32) = (0.0, 38.5);
 pub const HOUSE_RADIUS: f32 = 6.0 * FEET_TO_METERS; // 12 ft diameter → 6 ft radius
 pub const HOG_LINE_Y: f32 = 21.0;
-pub const BACK_LINE_Y: f32 = 42.0;
+/// Backline touches the outer house ring (tee + 6 ft).
+pub const BACK_LINE_Y: f32 = HOUSE_CENTER.1 + HOUSE_RADIUS;
 pub const HACK_Y: f32 = 2.0;
 
 // Stone physical properties
 pub const STONE_RADIUS: f32 = 0.15;
 pub const STONE_MASS: f32 = 20.0;
 pub const STONE_FRICTION: f32 = 0.015;
-/// Newton restitution for stone–stone contacts (Rapier, Average combine).
+/// Newton restitution for stone–stone contacts (Rapier, Max/Average combiners).
-/// Curling granite is nearly elastic on contact; low e makes takeouts feel like
-/// putty (both limp together). ~0.9 → both keep going along impact direction.
 pub const STONE_RESTITUTION: f32 = 0.9;
-/// Soft guard end of the throw slider. Weight 1 → MIN_SPEED.
+
-/// Calibrated with DRAW_VELOCITY so mid-slider (weight 5) lands near the tee.
+/// Stop offsets (feet relative to tee) for weights 1..=10 and hack.
-/// Shared with the frontend; binary sim does not clamp on it (clients send free velocity).
+/// Positive = past tee toward backline (behind the tee).
+pub const WEIGHT_STOP_OFFSET_FT: [f32; 10] =
+    [-11.0, -9.0, -7.0, -5.0, -3.0, -1.0, 0.0, 1.0, 3.0, 5.0];
+pub const HACK_STOP_OFFSET_FT: f32 = 12.0;
+
+/// m/s for weights 1..=10 (calibrated via open-ice stop distance).
+pub const WEIGHT_SPEEDS: [f32; 10] = [
+    2.2573, 2.2783, 2.2992, 2.3199, 2.3404, 2.3608, 2.3709, 2.3810, 2.4012, 2.4211,
+];
+pub const HACK_SPEED: f32 = 2.4899;
+/// Takeouts: open-ice stop at hack+N feet (N = 6,12,18,24).
+pub const BOARD_SPEED: f32 = 2.5492;
+pub const CONTROL_SPEED: f32 = 2.6408;
+pub const NORMAL_SPEED: f32 = 2.7448;
+pub const PEEL_SPEED: f32 = 2.8499;
+pub const BOARD_STOP_OFFSET_FT: f32 = HACK_STOP_OFFSET_FT + 6.0;
+pub const CONTROL_STOP_OFFSET_FT: f32 = HACK_STOP_OFFSET_FT + 15.0;
+pub const NORMAL_STOP_OFFSET_FT: f32 = HACK_STOP_OFFSET_FT + 25.0;
+pub const PEEL_STOP_OFFSET_FT: f32 = HACK_STOP_OFFSET_FT + 35.0;
+/// Tee-line weight (category 7).
+pub const DRAW_VELOCITY: f32 = WEIGHT_SPEEDS[6];
+/// UI soft end (weight 1).
 #[allow(dead_code)]
-pub const MIN_SPEED: f32 = 1.9;
+pub const MIN_SPEED: f32 = WEIGHT_SPEEDS[0];
-/// Heavy end of the throw slider. Weight 10 → MAX_SPEED.
+/// UI heavy end of draw weights (weight 10). Peel/hack sit above this.
-/// Keep span so weight 5 ≈ DRAW_VELOCITY (2.38).
 #[allow(dead_code)]
-pub const MAX_SPEED: f32 = 3.0;
+pub const MAX_SPEED: f32 = WEIGHT_SPEEDS[9];
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Hash, Default)]
 #[serde(rename_all = "snake_case")]
@@ -89,17 +108,12 @@ pub enum ClientMessage {
         velocity: f32,
         #[serde(default = "default_curl")]
         curl: i8,
-        #[serde(default = "default_friction")]
-        friction: f32,
     },
 }
 
 fn default_curl() -> i8 {
     1
 }
-fn default_friction() -> f32 {
-    1.0
-}
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct EndScore {
@@ -185,7 +199,7 @@ mod tests {
 
     #[test]
     fn throw_message_uses_velocity_not_weight() {
-        let json = r#"{"type":"throw","team":"team1","broom_x":0.5,"broom_y":38.5,"velocity":4.2,"curl":1,"friction":1.0}"#;
+        let json = r#"{"type":"throw","team":"team1","broom_x":0.5,"broom_y":38.5,"velocity":4.2,"curl":1}"#;
         let msg: ClientMessage = serde_json::from_str(json).unwrap();
         match msg {
             ClientMessage::Throw {