[modify] affine fns are generic; [add] safe-slot util

1 files changed, 7 insertions, 5 deletions

diff --git a/src/core/affine.lisp b/src/core/affine.lisp
index cabe17c..4585a81 100644
--- a/src/core/affine.lisp
+++ b/src/core/affine.lisp
@@ -15,7 +15,9 @@
      (setf (cached-model affine) nil
            (cached-projected-matrix affine) nil))))
 
-(defun scale-by (affine amount)
+
+
+(defmethod scale-by ((affine affine) amount)
   (with-slots (scale-x scale-y) affine
     (setf scale-x (* amount scale-x)
           scale-y (* amount scale-y))))
@@ -26,19 +28,19 @@
 (defun set-height-preserve-aspect (affine new-height)
   (scale-by affine (/ new-height (height affine) )))
 
-(defun width (affine)
+(defmethod width ((affine affine))
   (with-slots (scale-x base-width) affine
     (* scale-x base-width)))
 
-(defun height (affine)
+(defmethod height ((affine affine))
   (with-slots (scale-y base-height) affine
     (* scale-y base-height)))
 
-(defun (setf width) (newval affine)
+(defmethod (setf width) (newval (affine affine))
   (with-slots (scale-x base-width) affine
     (setf scale-x (coerce (/ newval base-width) 'single-float))))
 
-(defun (setf height) (newval affine)
+(defmethod (setf height) (newval (affine affine))
   (with-slots (scale-y base-height) affine
     (setf scale-y (coerce (/ newval base-height) 'single-float))))