1 files changed, 80 insertions, 0 deletions
diff --git a/assetFactory/texturePacker.cpp b/assetFactory/texturePacker.cpp
new file mode 100644
index 0000000..68a6010
--- /dev/null
+++ b/assetFactory/texturePacker.cpp
@@ -0,0 +1,80 @@
+#include "texturePacker.h"
+#include "collections.hpp"
+#include <algorithm>
+#include <cstdio>
+#include <numeric>
+#include <ostream>
+#include <set>
+
+TexturePacker::TexturePacker(std::span<const Image> in) :
+	inputImages {std::move(in)}, sortedIndexes {vectorOfN(inputImages.size(), size_t {})}
+{
+	std::sort(sortedIndexes.rbegin(), sortedIndexes.rend(), [this](const auto a, const auto b) {
+		return area(inputImages[a]) < area(inputImages[b]);
+	});
+}
+
+TexturePacker::Result
+TexturePacker::pack() const
+{
+	return pack(minSize());
+}
+
+TexturePacker::Result
+TexturePacker::pack(Size size) const
+{
+	using Spaces = std::set<Space>;
+	Spaces spaces {{{}, size}};
+
+	Positions result(inputImages.size());
+	for (const auto & idx : sortedIndexes) {
+		const auto & image = inputImages[idx];
+		if (const auto spaceItr = std::find_if(spaces.begin(), spaces.end(),
+					[image](const Space & s) {
+						return image.x <= s.size.x && image.y <= s.size.y;
+					});
+				spaceItr != spaces.end()) {
+			auto space = *spaceItr;
+			result[idx] = space.position;
+			spaces.erase(spaceItr);
+			if (space.size.x > image.x) {
+				spaces.emplace(Position {space.position.x + image.x, space.position.y},
+						Size {space.size.x - image.x, image.y});
+			}
+			if (space.size.y > image.y) {
+				spaces.emplace(Position {space.position.x, space.position.y + image.y},
+						Size {space.size.x, space.size.y - image.y});
+			}
+		}
+		else {
+			if (size.x < size.y) {
+				return pack({size.x * 2, size.y});
+			}
+			else {
+				return pack({size.x, size.y * 2});
+			}
+		}
+	}
+
+	return {result, size};
+}
+
+TexturePacker::Size
+TexturePacker::minSize() const
+{
+	return std::accumulate(inputImages.begin(), inputImages.end(), Size {1}, [](Size size, const Image & i) {
+		while (size.x < i.x) {
+			size.x *= 2;
+		}
+		while (size.y < i.y) {
+			size.y *= 2;
+		}
+		return size;
+	});
+}
+
+decltype(TexturePacker::Size::x)
+TexturePacker::area(const Size & size)
+{
+	return size.x * size.y;
+}