Add white noise pixmap generator

libs/pcg/include/psemek/pcg/white.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <psemek/geom/interval.hpp>
+#include <psemek/gfx/pixmap.hpp>
+
+#include <random>
+
+namespace psemek::pcg
+{
+
+	template <typename T = float, typename RNG>
+	gfx::basic_pixmap<T> white(std::size_t width, std::size_t height, RNG && rng, geom::interval<T> const & range)
+	{
+		using dist = std::conditional_t<std::is_floating_point_v<T>, std::uniform_real_distribution<T>, std::uniform_int_distribution<T>>;
+
+		dist d{range.min, range.max};
+
+		gfx::basic_pixmap<T> result(width, height);
+
+		for (std::size_t x = 0; x < width; ++x)
+			for (std::size_t y = 0; y < height; ++y)
+				result(x, y) = d(rng);
+
+		return result;
+	}
+
+}