Refactor to be functional

6 files changed, 58 insertions, 47 deletions

diff --git a/demo/platformer.scm b/demo/platformer.scm
index ff5caf7..3bad9bd 100644
--- a/demo/platformer.scm
+++ b/demo/platformer.scm
@@ -55,15 +55,17 @@
       (load-sounds! '((jump . "demo/assets/jump.wav"))))
 
     create: (lambda (game)
-      (let ((scene (game-load-scene! game "demo/assets/level-0.tmx")))
-        (scene-add-entity scene (make-player))
-        (scene-camera-target-set! scene 'player)))
+      (game-scene-set! game
+        (chain (game-load-scene! game "demo/assets/level-0.tmx")
+          (scene-add-entity _ (make-player))
+          (update-scene _ camera-target: 'player))))
 
     update: (lambda (game dt)
       (let* ((input  (game-input game))
              (scene  (game-scene game))
              (tm     (scene-tilemap scene))
              (player (update-player (car (scene-entities scene)) input tm)))
-        (scene-entities-set! scene (list player))))))
+        (game-scene-set! game
+          (update-scene scene entities: (list player)))))))
 
 (game-run! *game*)
diff --git a/demo/sandbox.scm b/demo/sandbox.scm
index 319ef80..6a6030f 100644
--- a/demo/sandbox.scm
+++ b/demo/sandbox.scm
@@ -159,16 +159,17 @@
 
     update: (lambda (game dt)
       (set! *demo-t* (+ *demo-t* dt))
-      (let* ((scene (game-scene game))
-             (tm    (scene-tilemap scene)))
-        (scene-update-entities scene (cut step-tweens <> dt))
-        (scene-update-entities scene (cut integrate-entity <> dt tm))
-        (scene-sync-groups! scene)
-        (scene-resolve-collisions scene)
-        (scene-update-entities scene
-          (lambda (e)
-            (if (entity-ref e #:gravity? #f)
-                (detect-on-solid e tm (scene-entities scene))
-                e)))))))
+      (let ((tm (scene-tilemap (game-scene game))))
+        (game-scene-set! game
+          (chain (game-scene game)
+            (scene-update-entities _ (cut step-tweens <> dt))
+            (scene-update-entities _ (cut integrate-entity <> dt tm))
+            (scene-sync-groups _)
+            (scene-resolve-collisions _)
+            (scene-update-entities _
+              (lambda (e)
+                (if (entity-ref e #:gravity? #f)
+                    (detect-on-solid e tm (scene-entities _))
+                    e)))))))))
 
 (game-run! *game*)
diff --git a/demo/scaling.scm b/demo/scaling.scm
index 983e583..f8bfdfb 100644
--- a/demo/scaling.scm
+++ b/demo/scaling.scm
@@ -53,7 +53,8 @@
              (ny (max 0 (min (- +height+ +box-size+)
                              (+ (entity-ref box #:y 0) vy))))
              (box (entity-set (entity-set box #:x nx) #:y ny)))
-        (scene-entities-set! scene (list box))))
+        (game-scene-set! game
+          (update-scene scene entities: (list box)))))
 
     render: (lambda (game)
       (let* ((renderer (game-renderer game))
diff --git a/demo/shmup.scm b/demo/shmup.scm
index 97779a8..ab09957 100644
--- a/demo/shmup.scm
+++ b/demo/shmup.scm
@@ -61,6 +61,10 @@
   (let ((y (entity-ref e #:y 0)))
     (and (> y -20) (< y (+ +screen-height+ 20)))))
 
+(define (scene-remove-dead scene)
+  (let ((dead (find-dead (scene-entities scene))))
+    (scene-filter-entities scene (lambda (e) (not (memq e dead))))))
+
 ;; ── Update helpers ───────────────────────────────────────────────────────────
 
 (define (player-vx input)
@@ -72,26 +76,27 @@
   (entity-set player #:x
     (max 0 (min (- +screen-width+ 16) (entity-ref player #:x 0)))))
 
-(define (update-player player input scene)
+(define (update-player player input)
   (let ((updated (chain player
                         (entity-set _ #:vx (player-vx input))
                         (apply-velocity-x _)
                         (clamp-player-x _))))
     (when (input-pressed? input 'a)
-      (play-sound 'shoot)
-      (scene-add-entity scene
-        (make-bullet (+ (entity-ref updated #:x 0) 6) 340)))
-    updated))
+      (play-sound 'shoot))
+    (if (input-pressed? input 'a)
+        (values updated
+                (list (make-bullet (+ (entity-ref updated #:x 0) 6) 340)))
+        (values updated '()))))
 
 (define (move-projectile e)
   (chain e
          (entity-set _ #:x (+ (entity-ref e #:x 0) (entity-ref e #:vx 0)))
          (entity-set _ #:y (+ (entity-ref e #:y 0) (entity-ref e #:vy 0)))))
 
-(define (maybe-spawn-enemy! scene)
-  (when (zero? (modulo *frame-count* +spawn-interval+))
-    (scene-add-entity scene
-      (make-enemy (+ 20 (* (pseudo-random-integer 28) 20))))))
+(define (maybe-spawn-enemies)
+  (if (zero? (modulo *frame-count* +spawn-interval+))
+      (list (make-enemy (+ 20 (* (pseudo-random-integer 28) 20))))
+      '()))
 
 ;; ── Render ───────────────────────────────────────────────────────────────────
 
@@ -132,22 +137,21 @@
 
     update: (lambda (game dt)
       (set! *frame-count* (+ *frame-count* 1))
-      (let* ((input  (game-input game))
-             (scene  (game-scene game))
-             (player (car (scene-entities scene)))
-             (player (update-player player input scene)))
-        (maybe-spawn-enemy! scene)
-        ;; Replace player, then move all projectiles
-        (scene-entities-set! scene
-          (cons player (filter (lambda (e) (not (eq? (entity-type e) 'player)))
-                               (scene-entities scene))))
-        (scene-update-entities scene
-          (lambda (e) (if (eq? (entity-type e) 'player) e (move-projectile e))))
-        ;; Remove bullet/enemy collisions, then out-of-bounds
-        (let ((dead (find-dead (scene-entities scene))))
-          (scene-filter-entities scene (lambda (e) (not (memq e dead)))))
-        (scene-filter-entities scene
-          (lambda (e) (or (eq? (entity-type e) 'player) (in-bounds? e))))))
+      (let* ((input   (game-input game))
+             (scene   (game-scene game))
+             (player  (car (scene-entities scene))))
+        (receive (player new-entities) (update-player player input)
+          (let* ((others  (filter (lambda (e) (not (eq? (entity-type e) 'player)))
+                                  (scene-entities scene)))
+                 (spawned (maybe-spawn-enemies))
+                 (all     (cons player (append new-entities spawned others))))
+            (game-scene-set! game
+              (chain (update-scene scene entities: all)
+                (scene-update-entities _
+                  (lambda (e) (if (eq? (entity-type e) 'player) e (move-projectile e))))
+                (scene-remove-dead _)
+                (scene-filter-entities _
+                  (lambda (e) (or (eq? (entity-type e) 'player) (in-bounds? e))))))))))
 
     render: (lambda (game)
       (for-each (cut draw-shmup-entity (game-renderer game) <>)
diff --git a/demo/topdown.scm b/demo/topdown.scm
index 7e5bd62..1bf6536 100644
--- a/demo/topdown.scm
+++ b/demo/topdown.scm
@@ -43,15 +43,17 @@
     title: "Demo: Top-down Explorer" width: 600 height: 400
 
     create: (lambda (game)
-      (let ((scene (game-load-scene! game "demo/assets/level-0.tmx")))
-        (scene-add-entity scene (make-player))
-        (scene-camera-target-set! scene 'player)))
+      (game-scene-set! game
+        (chain (game-load-scene! game "demo/assets/level-0.tmx")
+          (scene-add-entity _ (make-player))
+          (update-scene _ camera-target: 'player))))
 
     update: (lambda (game dt)
       (let* ((input  (game-input game))
              (scene  (game-scene game))
              (player (update-player (car (scene-entities scene))
                                     input (scene-tilemap scene))))
-        (scene-entities-set! scene (list player))))))
+        (game-scene-set! game
+          (update-scene scene entities: (list player)))))))
 
 (game-run! *game*)
diff --git a/demo/tweens.scm b/demo/tweens.scm
index 7ed2372..d036b6b 100644
--- a/demo/tweens.scm
+++ b/demo/tweens.scm
@@ -82,8 +82,9 @@
           background: '(26 28 34))))
 
     update: (lambda (game dt)
-      (scene-update-entities (game-scene game)
-        (cut step-tweens <> dt)))
+      (game-scene-set! game
+        (scene-update-entities (game-scene game)
+          (cut step-tweens <> dt))))
 
     render: (lambda (game)
       (draw-ease-labels! (game-renderer game)