Add spawn points (#71)

Reviewed-on: #71
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/match_loading.rs

@@ -21,7 +21,6 @@ use crate::{
     },
     input::{LocalInputAssignments, LocalInputSource},
     match_runtime::MatchState,
-    math::{int::FGi32, vec::FGVec2},
     netcode::{
         GGRSCfg,
         session::{ConnectionStatus, SessionConfig, create_session},
@@ -277,7 +276,7 @@ pub fn prepare_match(
     if !valid_player_handles(&config.players) {
         fail_match(
             &mut next_state,
-            "player handles must be unique and cover 0..player_count",
+            "player handles must be unique and non-empty",
         );
         return;
     }
@@ -287,6 +286,20 @@ pub fn prepare_match(
         return;
     }
 
+    let stage_handle = stage_registry
+        .get(config.stage)
+        .expect("Initialization check should ensure all stages exist");
+    let stage_manifest = stage_manifests
+        .get(&stage_handle)
+        .expect("Initialization check should ensure stage manifests are kept alive");
+    let spawn_positions = match stage_manifest.neutral_spawn_positions(config.players.len()) {
+        Ok(positions) => positions,
+        Err(error) => {
+            fail_match(&mut next_state, &error);
+            return;
+        }
+    };
+
     if assets.fighters.len() != config.players.len() {
         fail_match(
             &mut next_state,
@@ -449,7 +462,8 @@ pub fn prepare_match(
         ));
     }
 
-    let session_config = match SessionConfig::from_args(&args, config.players.len()) {
+    let session_player_count = player_count_for_handles(&config.players);
+    let session_config = match SessionConfig::from_args(&args, session_player_count) {
         Ok(config) => config,
         Err(error) => {
             fail_match(
@@ -459,7 +473,7 @@ pub fn prepare_match(
             return;
         }
     };
-    let session = match create_session(&args, config.players.len()) {
+    let session = match create_session(&args, session_player_count) {
         Ok(session) => session,
         Err(error) => {
             fail_match(
@@ -472,12 +486,6 @@ pub fn prepare_match(
 
     let root = commands.spawn((Name::new("Match"), MatchRoot)).id();
 
-    let stage_handle = stage_registry
-        .get(config.stage)
-        .expect("Initialization check should ensure all stages exist");
-    let stage_manifest = stage_manifests
-        .get(&stage_handle)
-        .expect("Initialization check should ensure stage manifests are kept alive");
     stage::spawn_stage(
         &mut commands,
         root,
@@ -487,14 +495,15 @@ pub fn prepare_match(
     );
 
     let mut fighter_roster = Vec::with_capacity(config.players.len());
-    for (index, (player, (scene, animations, attack_scripts, manifest_handle, model_scale, ecb_bone_indices))) in
+
+    for (spawn_index, (player, (scene, animations, attack_scripts, manifest_handle, model_scale, ecb_bone_indices))) in
         config.players.iter().zip(prepared).enumerate()
     {
-        let spawn_x = (index as i32 * 2 + 1 - config.players.len() as i32) * 5;
+        let spawn_point = spawn_positions[spawn_index];
         fighter_roster.push(spawn_fighter(
             &mut commands,
             player.handle,
-            FGVec2::new(FGi32::from_num(spawn_x), FGi32::lit("12.5")),
+            spawn_point,
             manifest_handle.clone(),
             model_scale,
             animations,
@@ -518,12 +527,22 @@ fn fail_match(next_state: &mut NextState<AppState>, message: &str) {
 }
 
 fn valid_player_handles(players: &[MatchPlayer]) -> bool {
-    let mut handles = players
+    if players.is_empty() {
+        return false;
+    }
+
+    let mut handles = players.iter().map(|player| player.handle).collect::<Vec<_>>();
+    handles.sort_unstable();
+    handles.windows(2).all(|handles| handles[0] != handles[1])
+        && handles.last().is_none_or(|handle| *handle != usize::MAX)
+}
+
+fn player_count_for_handles(players: &[MatchPlayer]) -> usize {
+    players
         .iter()
         .map(|player| player.handle)
-        .collect::<Vec<_>>();
-    handles.sort_unstable();
-    handles == (0..players.len()).collect::<Vec<_>>()
+        .max()
+        .map_or(0, |handle| handle + 1)
 }
 
 pub fn cleanup_match(
@@ -590,6 +609,23 @@ mod tests {
         assert!(!valid_player_handles(&players));
     }
 
+    #[test]
+    fn player_handles_may_have_gaps() {
+        let players = [
+            MatchPlayer {
+                handle: 0,
+                fighter: FighterId::TestFighter,
+            },
+            MatchPlayer {
+                handle: 2,
+                fighter: FighterId::TestFighter,
+            },
+        ];
+
+        assert!(valid_player_handles(&players));
+        assert_eq!(player_count_for_handles(&players), 3);
+    }
+
     #[test]
     fn match_rules_reject_zero_limits() {
         assert!(