X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=moebius2.git;a=blobdiff_plain;f=common.c;h=3b036aaa29f54508a5708a1965347734dc5cfa5e;hp=32701815aa753bcd1e43a4e71ee5d1cd1c43214b;hb=c9f085069bc4e555689dffedbfa08af250772f2a;hpb=ca6581b23c843e3117d3450a4ecf13bd6b71b8a5

diff --git a/common.c b/common.c
index 3270181..3b036aa 100644
--- a/common.c
+++ b/common.c
@@ -51,12 +51,16 @@ void xprod(double r[D3], const double a[D3], const double b[D3]) {
   r[2]= a[0]*b[1] - a[1]*b[0];
 }
 
-void xprod_norm(double r[D3], const double a[D3], const double b[D3],
-		double absepsilon, double one) {
+void normalise(double v[D3], double one, double absepsilon) {
   int k;
+  double multby= one/(magnD(v) + absepsilon);
+  K v[k] *= multby;
+}
+
+void xprod_norm(double r[D3], const double a[D3], const double b[D3],
+		double one, double absepsilon) {
   xprod(r,a,b);
-  double multby= one/(magnD(r) + absepsilon);
-  K r[k] *= multby;
+  normalise(r, absepsilon, one);
 }
 
 double dotprod(const double a[D3], const double b[D3]) {
@@ -78,4 +82,4 @@ void gsldie(int l, const char *what, int status) {
 
 void diee(const char *what) { perror(what); exit(16); }
 void fail(const char *emsg) { fputs(emsg,stderr); exit(12); }
-void flushoutput(void) { if (fflush(stdout)||ferror(stdout)) diee("stdout"); }
+void flushoutput(void) { if (ferror(stdout)||fflush(stdout)) diee("stdout"); }