From 98b5811d8b50d20f8c15e9b202f0d3f0457df58b Mon Sep 17 00:00:00 2001
From: Colin Okay <colin@cicadas.surf>
Date: Thu, 30 Jun 2022 09:29:28 -0500
Subject: [modify] affine fns are generic; [add] safe-slot util

---
 examples/02-moving-bitmp.lisp |  2 +-
 src/core/affine.lisp          | 12 +++++++-----
 src/core/unit.lisp            |  8 ++++++--
 src/protocol.lisp             | 26 ++++++++++++++++++++++++++
 src/utils.lisp                |  7 +++++++
 5 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/examples/02-moving-bitmp.lisp b/examples/02-moving-bitmp.lisp
index 7cb03d3..52cf0ca 100644
--- a/examples/02-moving-bitmp.lisp
+++ b/examples/02-moving-bitmp.lisp
@@ -51,7 +51,7 @@
             (ww::add-handler
              target
              (ww::on-perframe ()
-               (with-slots ((cx ww::x) (cy ww::y)) target 
+               (with-accessors ((cx ww::x) (cy ww::y)) target 
                  (if (and (= cx destx) (= cy desty))
                      (progn
                        (remhash target *shared-anim-table*)
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))))
 
diff --git a/src/core/unit.lisp b/src/core/unit.lisp
index 20e05e2..fb02f08 100644
--- a/src/core/unit.lisp
+++ b/src/core/unit.lisp
@@ -3,8 +3,9 @@
 (in-package #:wheelwork)
 
 (defclass/std unit ()
-  ((cached-application  :a)
-   (container :with :a)))
+  ((cached-application :a)
+   (container :with :a)
+   (visiblep :with :std t)))
 
 (defmethod (setf closer-mop:slot-value-using-class) :after
     (newval class (unit unit) slot)
@@ -28,3 +29,6 @@ in this application."
               (rec unit)))))
 
 
+(defmethod render :around ((unit unit))
+  (when (unit-visiblep unit)
+    (call-next-method)))
diff --git a/src/protocol.lisp b/src/protocol.lisp
index f8386a6..bd436e6 100644
--- a/src/protocol.lisp
+++ b/src/protocol.lisp
@@ -33,3 +33,29 @@
 (defgeneric ensure-loaded (asset)
   (:documentation "Ensures that the asset is loaded into memory and
   ready for use. Returns the asset."))
+
+(defgeneric scale-by (thing amount)
+  (:documentation "Scale horizontal and vertical dimensions of THING by AMOUNT"))
+
+(defgeneric width (thing)
+  (:documentation "Returns the effective width, in screen coordinates, of the object in question"))
+
+(defgeneric (setf width) (new-width thing)
+  (:documentation "Sets the effective width of thing to new-width."))
+
+(defgeneric height (thing)
+  (:documentation "Returns effective height, in screen coordinates, of the object in question."))
+
+(defgeneric (setf height) (new-height thing)
+  (:documentation "sets the effective height of thing to new-height"))
+
+(defgeneric rotation (thing))
+(defgeneric (setf rotation) (newval thing))
+(defgeneric x (thing))
+(defgeneric (setf x) (newval thing))
+(defgeneric y (thing))
+(defgeneric (setf y) (newval thing))
+(defgeneric scale-x (thing))
+(defgeneric (setf scale-x) (newvval thing))
+(defgeneric scale-y (thing))
+(defgeneric (setf scale-y) (newval thing))
diff --git a/src/utils.lisp b/src/utils.lisp
index e0f6dcd..3598ec3 100644
--- a/src/utils.lisp
+++ b/src/utils.lisp
@@ -7,3 +7,10 @@
 (defun radians (degrees)
   "Converse DEGREES to radians"
   (* degrees +pi-over-180+))
+
+(defun safe-slot (object slot &optional default)
+  (if-let (val (and (slot-exists-p object slot)
+                    (slot-boundp object slot)
+                    (slot-value object slot)))
+    val
+    default))
-- 
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