feat(英雄合并): 支持三合一合并并实现链式合并

- 将合并条件从两个英雄改为三个英雄
- 重构合并逻辑，提取 mergeGroupHeroes 方法处理合并过程
- 新增链式合并功能，当满足条件时自动触发连续合并
- 添加 countMergeHeroes 方法统计可合并英雄数量
- 优化代码结构，提高可维护性

assets/script/game/map/MissionHeroComp.ts

@@ -58,34 +58,22 @@ export class MissionHeroCompComp extends CCComp {
     }
 
     private async call_hero(event: string, args: any){
+        if (this.is_merging) return;
         const uuid = Number(args?.uuid ?? 1001);
         const hero_lv = Math.max(1, Number(args?.hero_lv ?? 1));
+        this.addHero(uuid, hero_lv);
         const aliveHeroes = this.getAliveHeroes();
-        const mergeHeroes = this.pickMergeHeroes(aliveHeroes, uuid, hero_lv);
+        const mergeHeroes = this.pickMergeHeroes(aliveHeroes, uuid, hero_lv, 3);
-        if (mergeHeroes.length === 2) {
+        if (mergeHeroes.length === 3) {
-            if (this.is_merging) return;
             this.is_merging = true;
             try {
-                let sumAp = 0;
+                const mergedLv = await this.mergeGroupHeroes(mergeHeroes, uuid, hero_lv);
-                let sumHpMax = 0;
+                await this.tryChainMerge(uuid, mergedLv);
-                for (let i = 0; i < mergeHeroes.length; i++) {
-                    const model = mergeHeroes[i].get(HeroAttrsComp);
-                    if (!model) continue;
-                    sumAp += model.ap;
-                    sumHpMax += model.hp_max;
-                }
-                let hero_pos = 0;
-                const landingPos:Vec3 = HeroPos[hero_pos].pos;
-                const spawnPos:Vec3 = v3(landingPos.x, landingPos.y + MissionHeroCompComp.HERO_DROP_HEIGHT, 0);
-                await this.mergeDestroyAtBirth(mergeHeroes, spawnPos);
-                await this.playMergeBoomFx(spawnPos);
-                this.addMergedHero(uuid, hero_lv + 1, sumAp, sumHpMax);
             } finally {
                 this.is_merging = false;
             }
             return;
         }
-        this.addHero(uuid, hero_lv);
     }
        /** 添加英雄 */
     private addHero(uuid:number=1001,hero_lv:number=1) {
@@ -99,14 +87,15 @@ export class MissionHeroCompComp extends CCComp {
         return hero;
     }
 
-    private addMergedHero(uuid:number, hero_lv:number, ap:number, hp_max:number) {
+    private addMergedHero(uuid:number, hero_lv:number, ap:number, hp_max:number): number {
         const hero = this.addHero(uuid, hero_lv);
         const model = hero.get(HeroAttrsComp);
-        if (!model) return;
+        if (!model) return hero_lv;
         model.ap = Math.max(0, ap);
         model.hp_max = Math.max(1, hp_max);
         model.hp = model.hp_max;
         model.dirty_hp = true;
+        return model.lv;
     }
 
     private getAliveHeroes(): Hero[] {
@@ -121,7 +110,7 @@ export class MissionHeroCompComp extends CCComp {
         return heroes;
     }
 
-    private pickMergeHeroes(aliveHeroes: Hero[], uuid: number, hero_lv: number): Hero[] {
+    private pickMergeHeroes(aliveHeroes: Hero[], uuid: number, hero_lv: number, needCount: number = 3): Hero[] {
         const mergeHeroes: Hero[] = [];
         for (let i = 0; i < aliveHeroes.length; i++) {
             const model = aliveHeroes[i].get(HeroAttrsComp);
@@ -129,11 +118,23 @@ export class MissionHeroCompComp extends CCComp {
             if (model.hero_uuid !== uuid) continue;
             if (model.lv !== hero_lv) continue;
             mergeHeroes.push(aliveHeroes[i]);
-            if (mergeHeroes.length === 2) break;
+            if (mergeHeroes.length === needCount) break;
         }
         return mergeHeroes;
     }
 
+    private countMergeHeroes(aliveHeroes: Hero[], uuid: number, hero_lv: number): number {
+        let count = 0;
+        for (let i = 0; i < aliveHeroes.length; i++) {
+            const model = aliveHeroes[i].get(HeroAttrsComp);
+            if (!model) continue;
+            if (model.hero_uuid !== uuid) continue;
+            if (model.lv !== hero_lv) continue;
+            count += 1;
+        }
+        return count;
+    }
+
     private mergeDestroyAtBirth(mergeHeroes: Hero[], spawnPos: Vec3): Promise<void> {
         return new Promise((resolve) => {
             let doneCount = 0;
@@ -179,6 +180,41 @@ export class MissionHeroCompComp extends CCComp {
         });
     }
 
+    private async mergeGroupHeroes(mergeHeroes: Hero[], uuid: number, hero_lv: number): Promise<number> {
+        let sumAp = 0;
+        let sumHpMax = 0;
+        for (let i = 0; i < mergeHeroes.length; i++) {
+            const model = mergeHeroes[i].get(HeroAttrsComp);
+            if (!model) continue;
+            sumAp += model.ap;
+            sumHpMax += model.hp_max;
+        }
+        let hero_pos = 0;
+        const landingPos:Vec3 = HeroPos[hero_pos].pos;
+        const spawnPos:Vec3 = v3(landingPos.x, landingPos.y + MissionHeroCompComp.HERO_DROP_HEIGHT, 0);
+        await this.mergeDestroyAtBirth(mergeHeroes, spawnPos);
+        await this.playMergeBoomFx(spawnPos);
+        return this.addMergedHero(uuid, hero_lv + 1, sumAp, sumHpMax);
+    }
+
+    private async tryChainMerge(uuid: number, startLv: number) {
+        let checkLv = Math.max(1, startLv);
+        let guard = 0;
+        while (guard < 20) {
+            guard += 1;
+            const aliveHeroes = this.getAliveHeroes();
+            const sameCount = this.countMergeHeroes(aliveHeroes, uuid, checkLv);
+            if (sameCount < 3) {
+                break;
+            }
+            const mergeHeroes = this.pickMergeHeroes(aliveHeroes, uuid, checkLv, 3);
+            if (mergeHeroes.length < 3) {
+                break;
+            }
+            checkLv = await this.mergeGroupHeroes(mergeHeroes, uuid, checkLv);
+        }
+    }
+