From 027053b11a3a5d861ed2fa2db245388bd95ac246 Mon Sep 17 00:00:00 2001
From: Gene Pasquet <dev@etenil.net>
Date: Sun, 5 Apr 2026 19:47:05 +0100
Subject: Progress

---
 engine.scm | 54 ++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 42 insertions(+), 12 deletions(-)

(limited to 'engine.scm')

diff --git a/engine.scm b/engine.scm
index 73e88f0..553dddf 100644
--- a/engine.scm
+++ b/engine.scm
@@ -6,6 +6,7 @@
         (prefix sdl2 "sdl2:")
         (prefix sdl2-ttf "ttf:")
         (prefix sdl2-image "img:")
+        (srfi 69)
         defstruct
         downstroke/world
         downstroke/input
@@ -26,7 +27,9 @@
   create-hook    ;; (lambda (game) ...)
   update-hook    ;; (lambda (game dt) ...)
   render-hook    ;; (lambda (game) ...) — post-render overlay
-  scene)         ;; current scene struct; #f until create: runs
+  scene          ;; current scene struct; #f until create: runs
+  states         ;; hash-table of name → state-plist
+  active-state)  ;; symbol or #f — currently active state name
 
 ;; Store the auto-generated constructor as make-game*
 (define make-game* make-game)
@@ -54,7 +57,9 @@
     preload-hook: preload
     create-hook:  create
     update-hook:  update
-    render-hook:  render))
+    render-hook:  render
+    states:       (make-hash-table)
+    active-state: #f))
 
 ;; ── Convenience accessors ──────────────────────────────────────────────────
 
@@ -70,6 +75,27 @@
 (define (game-asset-set! game key value)
   (asset-set! (game-assets game) key value))
 
+;; ── Named scene states ────────────────────────────────────────────────────
+
+;; Construct a state plist with lifecycle hooks.
+(define (make-game-state #!key (create #f) (update #f) (render #f))
+  (list #:create create #:update update #:render render))
+
+;; Retrieve a value from a state plist.
+(define (state-hook state key)
+  (get-keyword key state (lambda () #f)))
+
+;; Register a named state. name is a symbol; state is a make-game-state plist.
+(define (game-add-state! game name state)
+  (hash-table-set! (game-states game) name state))
+
+;; Transition to a named state. Calls the state's create: hook if present.
+(define (game-start-state! game name)
+  (game-active-state-set! game name)
+  (let* ((state  (hash-table-ref (game-states game) name))
+         (create (state-hook state #:create)))
+    (when create (create game))))
+
 ;; ── game-run! ──────────────────────────────────────────────────────────────
 ;; Main event loop and lifecycle orchestration
 
@@ -93,7 +119,7 @@
     (sdl2:create-window! (game-title game) 'centered 'centered
                          (game-width game) (game-height game) '()))
   (game-renderer-set! game
-    (sdl2:create-renderer! (game-window game) -1 '(accelerated vsync)))
+    (sdl2:create-renderer! (game-window game) -1 '(accelerated)))
 
   ;; 3. preload: hook — user loads assets here
   (when (game-preload-hook game)
@@ -119,15 +145,19 @@
                                          (game-input-config game))))
         (game-input-set! game input)
         (unless (input-held? input 'quit)
-          ;; update: hook — user game logic
-          (when (game-update-hook game)
-            ((game-update-hook game) game dt))
-          ;; render: engine draws world, then user overlay
-          (sdl2:render-clear! (game-renderer game))
-          (when (game-scene game)
-            (render-scene! (game-renderer game) (game-scene game)))
-          (when (game-render-hook game)
-            ((game-render-hook game) game))
+          ;; Dispatch to active state hooks, or fall back to game's own hooks
+          (let* ((active (game-active-state game))
+                 (state  (and active
+                              (hash-table-ref/default (game-states game) active #f)))
+                 (update-fn (or (and state (state-hook state #:update))
+                                (game-update-hook game)))
+                 (render-fn (or (and state (state-hook state #:render))
+                                (game-render-hook game))))
+            (when update-fn (update-fn game dt))
+            (sdl2:render-clear! (game-renderer game))
+            (when (game-scene game)
+              (render-scene! (game-renderer game) (game-scene game)))
+            (when render-fn (render-fn game)))
           (sdl2:render-present! (game-renderer game))
           (sdl2:delay! (game-frame-delay game))
           (loop now)))))
-- 
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