Use entities as platforms

1 files changed, 12 insertions, 0 deletions

diff --git a/tests/physics-test.scm b/tests/physics-test.scm
index 04ec6bb..a5b40e9 100644
--- a/tests/physics-test.scm
+++ b/tests/physics-test.scm
@@ -376,6 +376,18 @@
       (test-equal "a pushed up by 3" -3 (entity-ref ra #:y 0))
       (test-equal "b pushed down by 3" 13 (entity-ref rb #:y 0))))
 
+  (test-group "immovable: landing uses vertical separation when horizontal overlap is shallower"
+    ;; Without the landing rule, ovx < ovy would pick horizontal separation and shove the
+    ;; mover sideways off a narrow platform. Box center remains above shelf center → snap on top.
+    (let* ((shelf (list #:type 'static #:x 100 #:y 200 #:width 16 #:height 16
+                       #:solid? #t #:immovable? #t))
+           (box (list #:type 'box #:x 92 #:y 196 #:width 16 #:height 16
+                        #:solid? #t #:immovable? #f #:vx 0 #:vy 0))
+           (result (resolve-entity-collisions (list shelf box)))
+           (box2 (list-ref result 1)))
+      (test-equal "box rests on shelf top (y = shelf_y - height)" 184 (entity-ref box2 #:y 0))
+      (test-equal "vy zeroed" 0 (entity-ref box2 #:vy 0))))
+
   (test-group "non-solid entity ignored"
     (let* ((a (make-solid 0 0 16 16))
            (b (list #:type 'goal #:x 5 #:y 5 #:width 16 #:height 16))