From 103321cff74143f071f150cc0f644167ab30446a Mon Sep 17 00:00:00 2001
From: Sebastian Hoogen <github@sebastianhoogen.de>
Date: Sat, 15 Feb 2014 19:21:07 +0100
Subject: [PATCH] Use Part::Mirroing in importCSG

---
 src/Mod/OpenSCAD/OpenSCADUtils.py    | 39 ++++++++++++++++++++++++++++
 src/Mod/OpenSCAD/expandplacements.py |  7 +++++
 src/Mod/OpenSCAD/importCSG.py        |  9 +++++++
 3 files changed, 55 insertions(+)

diff --git a/src/Mod/OpenSCAD/OpenSCADUtils.py b/src/Mod/OpenSCAD/OpenSCADUtils.py
index 3e42e7374072..064da9effb90 100644
--- a/src/Mod/OpenSCAD/OpenSCADUtils.py
+++ b/src/Mod/OpenSCAD/OpenSCADUtils.py
@@ -195,10 +195,49 @@ def detsubmatrix(s):
 def isspecialorthogonalpython(submat,precision=4):
     return isorthogonal(submat,precision) and round(detsubmatrix(submat),precision)==1
 
+def isrotoinversionpython(submat,precision=4):
+    return isorthogonal(submat,precision) and round(detsubmatrix(submat),precision)==-1
+
 def isspecialorthogonal(mat,precision=4):
     return abs(mat.submatrix(3).isOrthogonal(10**(-precision))-1.0) < 10**(-precision) and \
             abs(mat.submatrix(3).determinant()-1.0) < 10**(-precision)
 
+def decomposerotoinversion(m,precision=4):
+    import FreeCAD
+    rmat = [[round(f,precision) for f in line] for line in fcsubmatrix(m)]
+    cmat = FreeCAD.Matrix()
+    if rmat ==[[-1,0,0],[0,1,0],[0,0,1]]:
+        cmat.scale(-1,1,1)
+        return m*cmat,FreeCAD.Vector(1)
+    elif rmat ==[[1,0,0],[0,-1,0],[0,0,1]]:
+        cmat.scale(1,-1,1)
+        return m*cmat, FreeCAD.Vector(0,1)
+    elif rmat ==[[1,0,0],[0,1,0],[0,0,-1]]:
+        cmat.scale(1,1,-1)
+        return m*cmat, FreeCAD.Vector(0,0,1)
+    else:
+        cmat.scale(1,1,-1)
+        return m*cmat, FreeCAD.Vector(0,0,1)
+
+def mirror2mat(nv,bv):
+    import FreeCAD
+    """calculate the transformation matrix of a mirror feature"""
+    mbef=FreeCAD.Matrix()
+    mbef.move(bv * -1)
+    maft=FreeCAD.Matrix()
+    maft.move(bv)
+    return maft*vec2householder(nv)*mbef
+
+def vec2householder(nv):
+    """calculated the householder matrix for a given normal vector"""
+    import FreeCAD
+    lnv=nv.dot(nv)
+    l=2/lnv if lnv > 0 else 0
+    hh=FreeCAD.Matrix(nv.x*nv.x*l,nv.x*nv.y*l,nv.x*nv.z*l,0,\
+                      nv.y*nv.x*l,nv.y*nv.y*l,nv.y*nv.z*l,0,\
+                      nv.z*nv.x*l,nv.z*nv.y*l,nv.z*nv.z*l,0,0,0,0,0)
+    return FreeCAD.Matrix()-hh
+
 def callopenscadmeshstring(scadstr):
     """Call OpenSCAD and return the result as a Mesh"""
     import Mesh,os
diff --git a/src/Mod/OpenSCAD/expandplacements.py b/src/Mod/OpenSCAD/expandplacements.py
index a3229fc8bddc..2db0b6b2abfd 100644
--- a/src/Mod/OpenSCAD/expandplacements.py
+++ b/src/Mod/OpenSCAD/expandplacements.py
@@ -96,6 +96,13 @@ def expandplacements(obj,placement):
         expandplacementsmatrix(obj,placement.toMatrix())
     elif likeprimitive(obj,False):
         obj.Placement=ownplacement
+    elif obj.isDerivedFrom('Part::Mirroring'):
+        import OpenSCADUtils
+        mm  = OpenSCADUtils.mirror2mat(obj.Normal,obj.Base)
+        #todo: set the base to 0,0,0
+        innerp=FreeCAD.Placement(mm * ownplacement.toMatrix() *mm)
+        expandplacements(obj.Source,innerp)
+        obj.Placement=FreeCAD.Placement()
     else:
         for outobj in obj.OutList:
             if obj.isDerivedFrom('Part::Extrusion'):
diff --git a/src/Mod/OpenSCAD/importCSG.py b/src/Mod/OpenSCAD/importCSG.py
index 8964d74a19c4..73af7b02d493 100644
--- a/src/Mod/OpenSCAD/importCSG.py
+++ b/src/Mod/OpenSCAD/importCSG.py
@@ -730,6 +730,15 @@ def p_multmatrix_action(p):
        if printverbose: print "Orthogonal"
        part.Placement=FreeCAD.Placement(transform_matrix).multiply(part.Placement)
        new_part = part
+    elif isrotoinversionpython(fcsubmatrix(transform_matrix)):
+        cmat,axisvec = decomposerotoinversion(transform_matrix)
+        new_part=doc.addObject("Part::Mirroring",'mirr_%s'%part.Name)
+        new_part.Source=part
+        new_part.Normal=axisvec
+        new_part.Placement=FreeCAD.Placement(cmat)
+        new_part.Label="mirrored %s" % part.Label
+        if gui:
+            part.ViewObject.hide()
     elif FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/OpenSCAD").\
         GetBool('useMultmatrixFeature'):
         from OpenSCADFeatures import MatrixTransform