Add Color struct

src/fart/color.d

@@ -0,0 +1,43 @@
+module fart.color;
+
+/**
+ * Structure to represent a RGBA color value.
+ */
+struct Color
+{
+    /** Red color component. */
+    double r;
+
+    /** Green color component. */
+    double g;
+
+    /** Blue color component. */
+    double b;
+
+    /** Alpha color component. */
+    double a;
+
+    /**
+     * Convert color to a 32-bit integer RGBA value.
+     *
+     * Each color component uses one byte.
+     */
+    public ubyte[] rgba32() const
+    {
+        return [toubyte(r), toubyte(g), toubyte(b), toubyte(a)];
+    }
+
+    /**
+     * Scale a floating point color component value to an unsigned 8-bit byte
+     * value.
+     *
+     * @param v
+     *   Floating point color component value.
+     *
+     * @return Unsigned 8-bit byte value for the color component.
+     */
+    private static ubyte toubyte(double v)
+    {
+        return cast(ubyte)(0xFF * v);
+    }
+}