make Color have a constexpr constructor and add Block class

quicktex/Block.h

@@ -0,0 +1,42 @@
+/*  Python-rgbcx 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
+
+namespace quicktex {
+
+/**
+ * Base class for all compressed blocks
+ *
+ * IMPORTANT: this class cannot contain any virtual methods or the vtable would add to the derived class size,
+ * it is only to act as a base class for type checking reasons. As such, it has limited utility on its own.
+ *
+ * @tparam N Block width in pixels
+ * @tparam M Block height in pixels
+ */
+template <int N, int M> class Block {
+    static_assert(N > 0);
+    static_assert(M > 0);
+
+   public:
+    static constexpr int Width = N;
+    static constexpr int Height = M;
+};
+
+}  // namespace quicktex

quicktex/Color.cpp

@@ -26,9 +26,9 @@
 
 namespace quicktex {
 
-Color::Color() { SetRGBA(0, 0, 0, 0xFF); }
+constexpr Color::Color() { SetRGBA(0, 0, 0, 0xFF); }
 
-Color::Color(uint8_t r, uint8_t g, uint8_t b, uint8_t a) { SetRGBA(r, g, b, a); }
+constexpr Color::Color(uint8_t r, uint8_t g, uint8_t b, uint8_t a) { SetRGBA(r, g, b, a); }
 
 Color::Color(Vector4Int v) { SetRGBA((uint8_t)v[0], (uint8_t)v[1], (uint8_t)v[2], (uint8_t)v[3]); }
 

quicktex/Color.h

@@ -34,9 +34,9 @@ class Color {
     uint8_t b;
     uint8_t a;
 
-    Color();
+    constexpr Color();
 
-    Color(uint8_t r, uint8_t g, uint8_t b, uint8_t a = 0xFF);
+    constexpr Color(uint8_t r, uint8_t g, uint8_t b, uint8_t a = 0xFF);
 
     Color(Vector4Int v);