Clearer API for slicing and dicing vectors, and also matrices

[libs/math.git] / source / linal / vector.h

diff --git a/source/linal/vector.h b/source/linal/vector.h
index 11292f7441dae7e7f69cefb58aadb73572f687e4..6dfe6ca0167fb3e1d57e65217003e3d700f6a3b3 100644 (file)
--- a/source/linal/vector.h
+++ b/source/linal/vector.h
@@ -53,6 +53,20 @@ public:
        const T &operator[](unsigned i) const { return *(&x+i); }
 };
 
+template<typename T>
+class VectorComponents<T, 4>
+{
+public:
+       T x, y, z, w;
+
+protected:
+       VectorComponents() { }
+
+public:
+       T &operator[](unsigned i) { return *(&x+i); }
+       const T &operator[](unsigned i) const { return *(&x+i); }
+};
+
 /**
 A general mathematical vector.
 */
@@ -64,9 +78,13 @@ public:
        Vector(const T *);
        Vector(T, T);
        Vector(T, T, T);
+       Vector(T, T, T, T);
        template<typename U>
        Vector(const Vector<U, N> &);
 
+       template<unsigned M>
+       Vector<T, M> slice(unsigned) const;
+
        Vector &operator*=(T);
        Vector &operator/=(T);
        Vector &operator+=(const Vector &);
@@ -108,6 +126,15 @@ inline Vector<T, N>::Vector(T x_, T y_, T z_)
        this->VectorComponents<T, 3>::z = z_;
 }
 
+template<typename T, unsigned N>
+inline Vector<T, N>::Vector(T x_, T y_, T z_, T w_)
+{
+       this->VectorComponents<T, 4>::x = x_;
+       this->VectorComponents<T, 4>::y = y_;
+       this->VectorComponents<T, 4>::z = z_;
+       this->VectorComponents<T, 4>::w = w_;
+}
+
 template<typename T, unsigned N>
 template<typename U>
 inline Vector<T, N>::Vector(const Vector<U, N> &v)
@@ -116,6 +143,47 @@ inline Vector<T, N>::Vector(const Vector<U, N> &v)
                (*this)[i] = v[i];
 }
 
+template<typename T, unsigned N>
+inline Vector<T, N+1> compose(const Vector<T, N> &v, T s)
+{
+       Vector<T, N+1> r;
+       for(unsigned i=0; i<N; ++i)
+               r[i] = v[i];
+       r[N] = s;
+       return r;
+}
+
+template<typename T, unsigned N>
+inline Vector<T, N+1> compose(T s, const Vector<T, N> &v)
+{
+       Vector<T, N+1> r;
+       for(unsigned i=0; i<N; ++i)
+               r[i] = v[i];
+       r[N] = s;
+       return r;
+}
+
+template<typename T, unsigned N, unsigned M>
+inline Vector<T, N+M> compose(const Vector<T, N> &v1, const Vector<T, M> &v2)
+{
+       Vector<T, N+M> r;
+       for(unsigned i=0; i<N; ++i)
+               r[i] = v1[i];
+       for(unsigned i=0; i<M; ++i)
+               r[N+i] = v2[i];
+       return r;
+}
+
+template<typename T, unsigned N>
+template<unsigned M>
+inline Vector<T, M> Vector<T, N>::slice(unsigned j) const
+{
+       Vector<T, M> r;
+       for(unsigned i=0; i<M; ++i)
+               r[i] = (*this)[j+i];
+       return r;
+}
+
 template<typename T, unsigned N>
 inline Vector<T, N> &Vector<T, N>::operator*=(T s)
 {
@@ -212,6 +280,7 @@ inline T inner_product(const Vector<T, N> &v1, const Vector<T, N> &v2)
 template<typename T, unsigned N>
 inline T Vector<T, N>::norm() const
 {
+       using std::sqrt;
        return sqrt(inner_product(*this, *this));
 }