Diff: Vec4.cpp

Revision:

0:785cff1e5a7c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Vec4.cpp	Mon Jan 04 15:19:10 2016 +0000
@@ -0,0 +1,124 @@
+/*
+    File:           Vec4.cpp
+
+    Function:       Implements Vec4.h
+
+    Author(s):      Andrew Willmott
+
+    Copyright:      (c) 1995-2001, Andrew Willmott
+
+*/
+
+
+#include "Vec4.h"
+//#include <cctype>
+//#include <iomanip>
+
+
+Vec4 &Vec4::MakeUnit(Int n, Real k)
+{
+    if (n == 0)
+    { elt[0] = k; elt[1] = vl_zero; elt[2] = vl_zero; elt[3] = vl_zero; }
+    else if (n == 1)
+    { elt[0] = vl_zero; elt[1] = k; elt[2] = vl_zero; elt[3] = vl_zero; }
+    else if (n == 2)
+    { elt[0] = vl_zero; elt[1] = vl_zero; elt[2] = k; elt[3] = vl_zero; }
+    else if (n == 3)
+    { elt[0] = vl_zero; elt[1] = vl_zero; elt[2] = vl_zero; elt[3] = k; }
+    else
+        _Error("(Vec4::MakeUnit) illegal unit vector");
+
+    return(SELF);
+}
+
+bool Vec4::operator == (const Vec4 &a) const
+{
+    return(elt[0] == a[0] && elt[1] == a[1] && elt[2] == a[2] && elt[3] == a[3]);
+}
+
+bool Vec4::operator != (const Vec4 &a) const
+{
+    return(elt[0] != a[0] || elt[1] != a[1] || elt[2] != a[2] || elt[3] != a[3]);
+}
+
+Vec4 cross(const Vec4 &a, const Vec4 &b, const Vec4 &c)
+{
+    Vec4 result;
+    // XXX can this be improved? Look at assembly.
+#define ROW(i)       a[i], b[i], c[i]
+#define DET(i,j,k)   dot(Vec3(ROW(i)), cross(Vec3(ROW(j)), Vec3(ROW(k))))
+
+    result[0] =  DET(1,2,3);
+    result[1] = -DET(0,2,3);
+    result[2] =  DET(0,1,3);
+    result[3] = -DET(0,1,2);
+
+    return(result);
+
+#undef ROW
+#undef DET
+}
+
+Vec3 proj(const Vec4 &v)
+{
+    Vec3 result;
+
+    Assert(v[3] != 0, "(Vec4/proj) last elt. is zero");
+
+    result[0] = v[0] / v[3];
+    result[1] = v[1] / v[3];
+    result[2] = v[2] / v[3];
+
+    return(result);
+}
+
+/*
+ostream &operator << (ostream &s, const Vec4 &v)
+{
+    Int w = s.width();
+
+    return(s << '[' << v[0] << ' ' << setw(w) << v[1] << ' '
+        << setw(w) << v[2] << ' ' << setw(w) << v[3] << ']');
+}
+
+istream &operator >> (istream &s, Vec4 &v)
+{
+    Vec4    result;
+    Char    c;
+
+    // Expected format: [1 2 3 4]
+
+    while (s >> c && isspace(c))
+        ;
+
+    if (c == '[')
+    {
+        s >> result[0] >> result[1] >> result[2] >> result[3];
+
+        if (!s)
+        {
+            cerr << "Error: Expected number while reading vector\n";
+            return(s);
+        }
+
+        while (s >> c && isspace(c))
+            ;
+
+        if (c != ']')
+        {
+            s.clear(ios::failbit);
+            cerr << "Error: Expected ']' while reading vector\n";
+            return(s);
+        }
+    }
+    else
+    {
+        s.clear(ios::failbit);
+        cerr << "Error: Expected '[' while reading vector\n";
+        return(s);
+    }
+
+    v = result;
+    return(s);
+}
+*/