1 files changed, 32 insertions, 0 deletions
diff --git a/src/LivingVillage.Desktop/LaunchScreen.fs b/src/LivingVillage.Desktop/LaunchScreen.fs
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+++ b/src/LivingVillage.Desktop/LaunchScreen.fs
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+namespace LivingVillage.Desktop
+
+/// 启动画面：固定的 60Hz 步进下，全部为帧计数的纯函数，确定性可复现。
+/// 标题淡入（revealProgress）、整屏暗幕退场（veilAlpha），Esc/空格可随时跳过。
+module LaunchScreen =
+
+    let durationFrames = 150L
+    let fadeInFrames = 45L
+    let title = "江南水乡"
+    let subtitle = "Living Village"
+    let skipHint = "ESC 或 空格 跳过"
+
+    let private clamp01 (value: float32) : float32 =
+        if value < 0.0f then 0.0f
+        elif value > 1.0f then 1.0f
+        else value
+
+    /// 0 = 完全未显示，1 = 完全显现。帧计数纯函数。
+    let revealProgress (frame: int64) : float32 =
+        if frame <= 0L then 0.0f
+        else clamp01 (float32 frame / float32 fadeInFrames)
+
+    /// 整屏暗幕：起手 1，随进程退到 0（1 -> 0）。
+    let veilAlpha (frame: int64) : float32 =
+        if frame <= 0L then 1.0f
+        elif frame >= durationFrames then 0.0f
+        else 1.0f - clamp01 (float32 frame / float32 durationFrames)
+
+    let isComplete (frame: int64) : bool = frame >= durationFrames
+
+    /// Esc 或 空格 触发跳过（调用方用“按下沿”结果，不做按键状态判定）。
+    let skipRequested (escapePressed: bool) (spacePressed: bool) : bool = escapePressed || spacePressed