添加游戏模式

private static final class MirrorMode implements GameModeDefinition {

    private final Logger logger;

    MirrorMode(Logger logger) {
        this.logger = logger;
    }

    @Override
    public String displayName() {
        return "镜像";
    }

    @Override
    public int mapLane(int lane, int laneCount) {
        return laneCount <= 1 ? lane : laneCount - 1 - lane;
    }

    @Override
    public boolean mirrorsPlayfield() {
        return true;
    }

    @Override
    public void onEnter(GameModeContext ctx) {
        logger.info("镜像模式进入 @" + ctx.musicTimeMs() + "ms");
    }

    @Override
    public void onExit(GameModeContext ctx) {
        logger.info("镜像模式退出 @" + ctx.musicTimeMs() + "ms");
    }
}

private static final String MOD_ID = "mirror_mode";

private static final RegistryKey<GameModeDefinition> MIRROR_MODE =
        RegistryKey.of(MOD_ID, "mirror", GameModeDefinition.class);

@Override
public void onPreInit(ModContext ctx) {
    ctx.registries().gameModes().register(MIRROR_MODE, new MirrorMode(ctx.getLogger()));
    ctx.getLogger().info("已注册游戏模式 " + MIRROR_MODE);
}

import com.seecmd.mod.api.capability.GameStateAccess;

// 入口类里保存 onInit 的上下文（模组级上下文可以长期持有）
private ModContext modContext;

@Override
public void onInit(ModContext ctx) {
    this.modContext = ctx;
}

// 需要切换时（例如你自己的全局快捷键回调里）
GameStateAccess state = modContext.capabilities().get(GameStateAccess.class);
if (state != null && !state.requestMode("mirror_mode:mirror")) {
    modContext.getLogger().warn("没有找到模式 mirror_mode:mirror");
}

@Override
public void renderOverlay(RenderCanvas canvas, GameModeContext ctx) {
    if (ctx.isPaused()) {
        return;
    }
    canvas.save();
    canvas.setAlpha(0.6);
    canvas.drawText("MIRROR", 640, 24,
            TextStyle.of(TextStyle.FontType.BOLD, 14, new Color(200, 220, 255),
                    TextStyle.TextAlignment.CENTER));
    canvas.restore();
}

@Override
public LaneInputMapper createLaneInputMapper() {
    return new LaneInputMapper() {
        private int laneCount;

        @Override
        public void init(int laneCount) {
            this.laneCount = laneCount;
        }

        @Override
        public int mapKeyToLane(int keyCode) {
            int lane = switch (keyCode) {
                case KeyEvent.VK_D -> 0;
                case KeyEvent.VK_F -> 1;
                case KeyEvent.VK_J -> 2;
                case KeyEvent.VK_K -> 3;
                default -> -1;
            };
            return lane < laneCount ? lane : -1;
        }

        @Override
        public Set<Integer> triggerKeys() {
            return Set.of(KeyEvent.VK_D, KeyEvent.VK_F, KeyEvent.VK_J, KeyEvent.VK_K);
        }
    };
}