Add matrix template

quicktex/Matrix.h

@@ -0,0 +1,50 @@
+/*  Quicktex Texture Compression Library
+    Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
+    Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
+    and licenced under the public domain
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <array>
+
+#include "Vec.h"
+
+namespace quicktex {
+template <typename T, size_t M, size_t N> class Matrix : Vec<Vec<T, N>, M> {
+    // N: width, M:height
+    // when using as a buffer for batches, vectors are actually *columns*
+   public:
+    Vec<T, N> &row(size_t m) { return this->at(m); }
+    const Vec<T, N> &row(size_t m) const { return this->at(m); }
+
+    Vec<T, M> get_column(size_t n) {
+        Vec<T, M> res;
+        for (unsigned m = 0; m < M; m++) { res[m] = row(m)[n]; }
+        return res;
+    }
+
+    void set_column(size_t n, const Vec<T, M> &col) {
+        for (unsigned m = 0; m < M; m++) { row(m)[n] = col[m]; }
+    }
+
+    std::array<T *, M> get_column_ptrs(size_t index) const {
+        std::array<T *, M> ptrs;
+        for (unsigned i = 0; i < M; i++) { ptrs[i] = &(row(i)[index]); }
+        return ptrs;
+    }
+};
+}  // namespace quicktex