From: Jean-baptiste Silvy <jean-baptiste.silvy@scilab.org>
Date: Mon, 31 Mar 2008 12:06:32 +0000 (+0000)
Subject: Add some geometric functions.
X-Git-Url: http://gitweb.scilab.org/?p=scilab.git;a=commitdiff_plain;h=14e4d4697b4b161277f03c2d82b14ef2619a211e

Add some geometric functions.
---

diff --git a/scilab/modules/graphics/includes/math_graphics.h b/scilab/modules/graphics/includes/math_graphics.h
index 688296c..8935afe 100644
--- a/scilab/modules/graphics/includes/math_graphics.h
+++ b/scilab/modules/graphics/includes/math_graphics.h
@@ -183,6 +183,18 @@ void crossProduct( const double v1[3], const double v2[3], double res[3] ) ;
 #define NORM_3D(v) ( sqrt( SQUARE_NORM_3D(v) ) )
 
 /**
+ * substraction of two vector
+ * @param res result of v1 - v2
+ */
+void vectSubstract3D( double v1[3], double v2[3], double res[3]);
+
+/**
+ * Multiply a vector by a scalar
+ * @param res scalar.v
+ */
+void scalarMult3D( double v[3], double scalar, double res[3]);
+
+/**
  * Normalize a 3D vector
  */
 void normalize3D( double vect[3] ) ;
diff --git a/scilab/modules/graphics/src/c/math_graphics.c b/scilab/modules/graphics/src/c/math_graphics.c
index 84e8226..1c9ae26 100644
--- a/scilab/modules/graphics/src/c/math_graphics.c
+++ b/scilab/modules/graphics/src/c/math_graphics.c
@@ -155,9 +155,28 @@ void iNormalize2d( int vect[2] )
 /*----------------------------------------------------------------------------*/
 void crossProduct( const double v1[3], const double v2[3], double res[3] )
 {
-  res[0] = v1[1] * v2[2] - v1[2] * v2[1] ;
-  res[1] = v1[2] * v2[0] - v1[0] * v2[2] ;
-  res[2] = v1[0] * v2[1] - v1[1] * v2[0] ;
+  /* save data to be able to use v1 o v2 as res */
+  double v10 = v1[0];
+  double v20 = v2[0];
+  double v11 = v1[1];
+  double v21 = v2[1];
+  res[0] = v11 * v2[2] - v1[2] * v21 ;
+  res[1] = v1[2] * v20 - v10 * v2[2] ;
+  res[2] = v10 * v21 - v11 * v20 ;
+}
+/*----------------------------------------------------------------------------*/
+void vectSubstract3D( double v1[3], double v2[3], double res[3])
+{
+  res[0] = v1[0] - v2[0];
+  res[1] = v1[1] - v2[1];
+  res[2] = v1[2] - v2[2];
+}
+/*----------------------------------------------------------------------------*/
+void scalarMult3D( double v[3], double scalar, double res[3])
+{
+  res[0] = scalar * v[0];
+  res[1] = scalar * v[1];
+  res[2] = scalar * v[2];
 }
 /*----------------------------------------------------------------------------*/
 void normalize3D( double vect[3] )