Merge pull request #173 from kaveh808/Kaveh-devel-4

STL format export

kons-9.asd

@@ -97,6 +97,7 @@
    (:file "src/plugins/poly-mesh")
    (:file "src/plugins/usd")
    (:file "src/plugins/obj")
+   (:file "src/plugins/stl")
    ))
 
 (asdf:defsystem #:kons-9/testsuite

src/plugins/obj.lisp

@@ -58,7 +58,7 @@
 (defparameter *obj-export-vref-offset* 1)
 
 (defmethod export-obj ((scene scene) filename)
-  (with-open-file (stream filename :direction :output :if-exists :overwrite :if-does-not-exist :create)
+  (with-open-file (stream filename :direction :output :if-exists :supersede :if-does-not-exist :create)
     (write-obj scene stream)))
 
 (defmethod write-obj ((scene scene) &optional (stream t) (matrix nil))

src/plugins/stl.lisp

@@ -0,0 +1,41 @@
+(in-package #:kons-9)
+
+;;;; stl format export =========================================================
+
+(defmethod export-stl ((polyh polyhedron) filename)
+  (with-open-file (stream filename :direction :output :if-exists :supersede :if-does-not-exist :create)
+    (write-stl polyh stream)))
+
+(defmethod write-stl ((polyh polyhedron) &optional (stream t))
+  (format stream "solid ~A -- kons-9 stl export -- https://github.com/kaveh808/kons-9~%" (name polyh))
+  (multiple-value-bind (lo hi)
+      (get-bounds polyh)
+    (declare (ignore hi))
+    ;; move polyh so no negative coords, and then triangulate it
+    (let ((tri-polyh (freeze-transform (translate-by (triangulate-polyhedron polyh) (p:negate lo)))))
+      ;; export data
+      (do-array (i f (faces tri-polyh))
+        (let ((n (aref (face-normals tri-polyh) i)))
+          (when (not (p:= n +origin+))    ;skip degenerate triangles
+            (format stream "  facet normal ~E ~E ~E~%" (p:x n) (p:y n) (p:z n)) ;scientific notation
+            (format stream "    outer loop~%")
+            (dolist (vref f)
+              (let ((v (aref (points tri-polyh) vref)))
+                (format stream "      vertex ~E ~E ~E~%" (p:x v) (p:y v) (p:z v)))) ;scientific notation
+            (format stream "    endloop~%")
+            (format stream "  endfacet~%")))))
+    (format stream "endsolid ~A~%" (name polyh))))
+
+
+
+
+;;; stl export test
+
+#|
+(export-stl (make-superquadric 16 16 20.0 0.2 0.2) "~/superq.stl")
+(export-stl (make-cube 20) "~/cube.stl")
+|#
+
+
+
+