aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/grid-geometry.lisp
diff options
context:
space:
mode:
authorColin Okay <colin@cicadas.surf>2022-07-17 12:42:42 -0500
committerColin Okay <colin@cicadas.surf>2022-07-17 12:42:42 -0500
commit53019e4770d1cf9999201e261fd6d93ab3c0d849 (patch)
treee3ff351b917577149705271c42aa877b665e6cd3 /src/grid-geometry.lisp
parentb72153a73875fc0081d072b90ac411c0eaef08a8 (diff)
[wip]
Diffstat (limited to 'src/grid-geometry.lisp')
-rw-r--r--src/grid-geometry.lisp70
1 files changed, 70 insertions, 0 deletions
diff --git a/src/grid-geometry.lisp b/src/grid-geometry.lisp
new file mode 100644
index 0000000..cef69f8
--- /dev/null
+++ b/src/grid-geometry.lisp
@@ -0,0 +1,70 @@
+;;; grid-geometry.lisp
+
+(in-package :wheelwork )
+
+(defmacro with-grid-line
+ ((x y) (start-x start-y) (end-x end-y) &body body)
+ "Execute BODY for X and Y assigned to integer values in a line
+connecting the integer point START-X , START-Y and END-X, END-Y. "
+ (with-gensyms (sx sy ex ey distance step progress xdiff ydiff)
+ `(loop
+ with ,sx = ,start-x
+ with ,sy = ,start-y
+ with ,ex = ,end-x
+ with ,ey = ,end-y
+ with ,xdiff = (- ,ex ,sx)
+ with ,ydiff = (- ,ey, sy)
+ with ,distance = (max (abs ,xdiff) (abs ,ydiff))
+ for ,step from 0 to ,distance
+ for ,progress = (if (zerop ,distance) 0.0 (/ ,step ,distance))
+ for ,x = (round (+ ,start-x (* ,progress ,xdiff)))
+ for ,y = (round (+ ,start-y (* ,progress ,ydiff)))
+ do (progn ,@body))))
+
+(defmacro with-grid-path
+ ((x y) (path &key autoclosep interiorp) &body body)
+ (with-gensyms (points x1 y1 x2 y2 more)
+ (let ((autoclose-block
+ (when autoclosep
+ `(destructuring-bind (,x2 ,y2) (first ,points)
+ (with-grid-line (,x2 ,y2) (,x1 ,y1) ,@body)))))
+ `(let ((,points ,path))
+ (loop
+ for ((,x1 ,y) (,x2 ,y2) . ,more) on ,points
+ while ,x2 do
+ (with-grid-line (,x ,y) (,x1 ,y1) (,x2 ,y2) ,@body)
+ finally (progn ,autoclose-block))))))
+
+(defun grid-bbox-for (poly)
+ "POLY is a list of pairs of xy coordinates. Return a pair of
+pairs, ((min-x min-y) (max-x max-y)), representing the bottom left and
+top right corners of the bounding box for POLY "
+ (loop for (x y) in poly
+ minimizing x into x-min
+ maximizing x into x-max
+ minimizing y into y-min
+ maximizing y into y-max
+ finally (return (list (list x-min y-min)
+ (list x-max y-max)))))
+
+(defmacro with-grid-poly-interior
+ ((x y) perimeter &body body)
+ "PERMIETER is expected to evaluate to a list of contiguous points,
+representing the permimeter a polygon in 2d space. Execute BODY for
+each point interior to this polygon."
+ (with-gensyms (points bottom left top right)
+ `(let ((,points ,permieter))
+ (destructuring-bind ((,left ,bottom) (,right ,top)) (grid-bbox-for ,points)
+ (loop )
+ )))
+ )
+
+(defmacro with-grid-circle
+ ((x y) (cx cy radius &key interiorp) &body body)
+ (with-gensyms (rad sx sy)
+ (let ((comparator
+ (if interiorp '>= '=)))
+ `(let ((,sx ,cx) (,sy ,cy) (,rad ,radius))
+ (with-grid-rect (,x ,y) ((- ,sx ,rad) (- ,sy ,rad) (+ ,sx ,rad) (+ ,sy ,rad))
+ (when (,comparator ,rad (round (euclidean-dist ,x ,y ,sx ,sy)))
+ ,@body))))))