[example] added a second keydown handler to sprite example

In order to control speed, but also to demonstrate that you can add as
many handlers for an event as you like.

1 files changed, 30 insertions, 17 deletions

diff --git a/examples/06-sprite.lisp b/examples/06-sprite.lisp
index 57916a5..2addfd7 100644
--- a/examples/06-sprite.lisp
+++ b/examples/06-sprite.lisp
@@ -8,7 +8,8 @@
 
 (defclass sprite-example (ww::application) ())
 (defclass dude (ww::sprite)
-  ((walkingp :accessor walkingp :initform nil)))
+  ((walkingp :accessor walkingp :initform nil)
+   (walking-speed :accessor walking-speed :initform 5)))
 
 (defun set-key-if-not (sprite key )
   "Sets the frame kyey for sprite if that key is not already set. Also
@@ -24,30 +25,41 @@
 (ww::defhandler move-by-face
     (ww::on-perframe (sprite)
       "When the sprite is walking, adjust its position."
-      (when (walkingp sprite) 
-        (case (ww::frameset-key sprite)
-          (:left
-           (decf (ww::x sprite) +walking-speed+))
-          (:right
-           (incf (ww::x sprite) +walking-speed+))
-          (:back
-           (incf (ww::y sprite) +walking-speed+))
-          (:front
-           (decf (ww::y sprite) +walking-speed+))))))
+      (with-slots (walkingp walking-speed) sprite 
+        (when walkingp
+          (case (ww::frameset-key sprite)
+            (:left
+             (decf (ww::x sprite) walking-speed))
+            (:right
+             (incf (ww::x sprite) walking-speed))
+            (:back
+             (incf (ww::y sprite) walking-speed))
+            (:front
+             (decf (ww::y sprite) walking-speed)))))))
 
 (ww::defhandler move-dude
-    (ww::on-keydown (target scancode)
+    (ww::on-keydown (sprite scancode)
       "Set sprite to walking and set the frameset appropriate to its direction."
-      (setf (walkingp target) t)
       (case scancode
         (:scancode-left
-         (set-key-if-not target :left))
+         (set-key-if-not sprite :left)
+         (setf (walkingp sprite) t))
         (:scancode-right
-         (set-key-if-not target :right))
+         (set-key-if-not sprite :right)
+         (setf (walkingp sprite) t))
         (:scancode-up
-         (set-key-if-not target :back))
+         (set-key-if-not sprite :back)
+         (setf (walkingp sprite) t))
         (:scancode-down
-         (set-key-if-not target :front)))))
+         (set-key-if-not sprite :front)
+         (setf (walkingp sprite) t)))))
+
+(ww::defhandler speed-control
+    (ww::on-keydown (sprite scancode)
+      "A second keydown handler, for controlling walking speed. "
+      (case scancode
+        (:scancode-u (incf (walking-speed sprite)))
+        (:scancode-d (decf (walking-speed sprite))))))
 
 (ww::defhandler stand
     (ww::on-keyup (target)
@@ -102,6 +114,7 @@
     (ww::add-handler dude #'move-by-face )
     (ww::add-handler dude #'move-dude)
     (ww::add-handler dude #'stand)
+    (ww::add-handler dude #'speed-control)
     (ww::refocus-on dude)
     (ww::add-unit app dude)))