feat: add engine.scm — game struct, make-game constructor, convenience accessors

1 files changed, 157 insertions, 0 deletions

diff --git a/tests/engine-test.scm b/tests/engine-test.scm
new file mode 100644
index 0000000..56b9a04
--- /dev/null
+++ b/tests/engine-test.scm
@@ -0,0 +1,157 @@
+(import scheme (chicken base) (chicken keyword) srfi-64 defstruct)
+
+;; --- Mocks ---
+
+(module sdl2 *
+  (import scheme (chicken base))
+  (define (set-main-ready!) #f)
+  (define (init! . args) #f)
+  (define (quit! . args) #f)
+  (define (get-ticks) 0)
+  (define (delay! ms) #f)
+  (define (pump-events!) #f)
+  (define (has-events?) #f)
+  (define (make-event) #f)
+  (define (poll-event! e) #f)
+  (define (num-joysticks) 0)
+  (define (is-game-controller? i) #f)
+  (define (game-controller-open! i) #f)
+  (define (create-window! . args) 'mock-window)
+  (define (create-renderer! . args) 'mock-renderer)
+  (define (destroy-window! . args) #f)
+  (define (render-clear! . args) #f)
+  (define (render-present! . args) #f)
+  (define (make-rect x y w h) (list x y w h))
+  (define (render-copy! . args) #f)
+  (define (render-copy-ex! . args) #f)
+  (define (create-texture-from-surface . args) #f))
+(import (prefix sdl2 "sdl2:"))
+
+(module sdl2-ttf *
+  (import scheme (chicken base))
+  (define (init!) #f))
+(import (prefix sdl2-ttf "ttf:"))
+
+(module sdl2-image *
+  (import scheme (chicken base))
+  (define (init! . args) #f))
+(import (prefix sdl2-image "img:"))
+
+;; --- Entity module (mock minimal structs) ---
+(module downstroke/entity *
+  (import scheme (chicken base)))
+(import downstroke/entity)
+
+;; --- Input module (mock) ---
+(module downstroke/input *
+  (import scheme (chicken base) defstruct)
+  (defstruct input-config
+    actions keyboard-map joy-button-map controller-button-map
+    joy-axis-bindings controller-axis-bindings deadzone)
+  (define-record input-state current previous)
+  (define *default-input-config*
+    (make-input-config
+      actions: '(up down left right a b start select quit)
+      keyboard-map: '((w . up) (up . up) (s . down) (down . down)
+                      (a . left) (left . left) (d . right) (right . right)
+                      (j . a) (z . a) (k . b) (x . b)
+                      (return . start) (escape . quit))
+      joy-button-map: '((0 . a) (1 . b) (7 . start) (6 . select))
+      controller-button-map: '((a . a) (b . b) (start . start) (back . select)
+                               (dpad-up . up) (dpad-down . down)
+                               (dpad-left . left) (dpad-right . right))
+      joy-axis-bindings: '((0 right left) (1 down up))
+      controller-axis-bindings: '((left-x right left) (left-y down up))
+      deadzone: 8000))
+  (define (create-input-state config)
+    (make-input-state '() '())))
+(import downstroke/input)
+
+;; --- World module (mock) ---
+(module downstroke/world *
+  (import scheme (chicken base) defstruct)
+  (defstruct camera x y)
+  (defstruct scene entities tilemap camera tileset-texture))
+(import downstroke/world)
+
+;; --- Assets module (real) ---
+(include "assets.scm")
+(import downstroke/assets)
+
+;; --- Renderer module (mock) ---
+(module downstroke/renderer *
+  (import scheme (chicken base))
+  (define (render-scene! . args) #f))
+(import downstroke/renderer)
+
+;; --- Engine module (real) ---
+(include "engine.scm")
+(import downstroke/engine)
+
+;; --- Tests ---
+
+(test-begin "engine")
+
+(test-group "make-game defaults"
+  (let ((g (make-game)))
+    (test-equal "default title"
+      "Downstroke Game"
+      (game-title g))
+    (test-equal "default width"
+      640
+      (game-width g))
+    (test-equal "default height"
+      480
+      (game-height g))
+    (test-equal "default frame-delay"
+      16
+      (game-frame-delay g))
+    (test-equal "scene starts as #f"
+      #f
+      (game-scene g))
+    (test-equal "window starts as #f"
+      #f
+      (game-window g))
+    (test-equal "renderer starts as #f"
+      #f
+      (game-renderer g))
+    (test-assert "assets registry is created"
+      (game-assets g))
+    (test-assert "input state is created"
+      (game-input g))))
+
+(test-group "make-game with keyword args"
+  (let ((g (make-game title: "My Game" width: 320 height: 240 frame-delay: 33)))
+    (test-equal "custom title" "My Game" (game-title g))
+    (test-equal "custom width" 320 (game-width g))
+    (test-equal "custom height" 240 (game-height g))
+    (test-equal "custom frame-delay" 33 (game-frame-delay g))))
+
+(test-group "game-asset and game-asset-set!"
+  (let ((g (make-game)))
+    (test-equal "missing key returns #f"
+      #f
+      (game-asset g 'no-such-asset))
+    (game-asset-set! g 'my-font 'font-object)
+    (test-equal "stored asset is retrievable"
+      'font-object
+      (game-asset g 'my-font))
+    (game-asset-set! g 'my-font 'updated-font)
+    (test-equal "overwrite replaces asset"
+      'updated-font
+      (game-asset g 'my-font))))
+
+(test-group "make-game hooks default to #f"
+  (let ((g (make-game)))
+    (test-equal "preload-hook is #f" #f (game-preload-hook g))
+    (test-equal "create-hook is #f"  #f (game-create-hook g))
+    (test-equal "update-hook is #f"  #f (game-update-hook g))
+    (test-equal "render-hook is #f"  #f (game-render-hook g))))
+
+(test-group "make-game accepts hook lambdas"
+  (let* ((called #f)
+         (g (make-game update: (lambda (game dt) (set! called #t)))))
+    (test-assert "update hook is stored"
+      (procedure? (game-update-hook g)))))
+
+(test-end "engine")