Clearer API for slicing and dicing vectors, and also matrices

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

diff --git a/source/linal/matrix.h b/source/linal/matrix.h
index f18eb2f4cfb52504214b84015688e46d0d7be121..929c48247e517aa47d837df1438c94465e25064a 100644 (file)
--- a/source/linal/matrix.h
+++ b/source/linal/matrix.h
@@ -30,6 +30,9 @@ public:
        T &operator()(unsigned i, unsigned j) { return element(i, j); }
        const T &operator()(unsigned i, unsigned j) const { return element(i, j); }
 
+       template<unsigned P, unsigned Q>
+       Matrix<T, P, Q> block(unsigned, unsigned) const;
+
        Matrix &operator*=(T);
        Matrix &operator/=(T);
        Matrix &operator+=(const Matrix &);
@@ -81,6 +84,17 @@ inline Matrix<T, M, N> Matrix<T, M, N>::from_rows(const Vector<T, N> *v)
        return m;
 }
 
+template<typename T, unsigned M, unsigned N>
+template<unsigned P, unsigned Q>
+inline Matrix<T, P, Q> Matrix<T, M, N>::block(unsigned y, unsigned x) const
+{
+       Matrix<T, P, Q> r;
+       for(unsigned j=0; j<P; ++j)
+               for(unsigned i=0; i<Q; ++i)
+                       r(j, i) = element(y+j, x+i);
+       return r;
+}
+
 template<typename T, unsigned M, unsigned N>
 inline Matrix<T, M, N> &Matrix<T, M, N>::operator*=(T s)
 {