World: factor out Section handling to a generic interface

src/World/Section.hpp

@@ -0,0 +1,110 @@
+/*
+  Copyright (c) 2015-2018, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#pragma once
+
+
+#include "../NBT/ByteArrayTag.hpp"
+#include "../NBT/CompoundTag.hpp"
+#include "../Resource/BlockType.hpp"
+
+#include <cstdint>
+#include <stdexcept>
+
+
+namespace MinedMap {
+namespace World {
+
+class Section {
+public:
+	static const size_t SIZE = 16;
+
+private:
+	size_t Y;
+	std::shared_ptr<const NBT::ByteArrayTag> blockLight;
+
+protected:
+	static size_t getIndex(size_t x, size_t y, size_t z) {
+		if (x >= SIZE || y >= SIZE || z >= SIZE)
+			throw std::range_error("Chunk::getIndex(): bad coordinates");
+
+		return SIZE*SIZE*y + SIZE*z + x;
+	}
+
+	static uint8_t getHalf(const uint8_t *v, size_t x, size_t y, size_t z) {
+		size_t i = getIndex(x, y, z);
+
+		if (i % 2)
+			return (v[i/2] >> 4);
+		else
+			return (v[i/2] & 0xf);
+	}
+
+	Section(const std::shared_ptr<const NBT::CompoundTag> &section);
+
+public:
+	virtual ~Section() {}
+
+	size_t getY() const { return Y; };
+
+	virtual const Resource::BlockType * getBlockStateAt(size_t x, size_t y, size_t z) const = 0;
+
+	uint8_t getBlockLightAt(size_t x, size_t y, size_t z) const {
+		if (!blockLight)
+			return 0;
+
+		return getHalf(blockLight->getValue(), x, y, z);
+	}
+
+	static std::unique_ptr<Section> makeSection(const std::shared_ptr<const NBT::CompoundTag> &section);
+};
+
+class LegacySection : public Section {
+private:
+	std::shared_ptr<const NBT::ByteArrayTag> blocks;
+	std::shared_ptr<const NBT::ByteArrayTag> data;
+
+
+	uint8_t getBlockAt(size_t x, size_t y, size_t z) const {
+		return blocks->getValue()[getIndex(x, y, z)];
+	}
+
+	uint8_t getDataAt(size_t x, size_t y, size_t z) const {
+		return getHalf(data->getValue(), x, y, z);
+	}
+
+public:
+	LegacySection(
+		const std::shared_ptr<const NBT::CompoundTag> &section,
+		std::shared_ptr<const NBT::ByteArrayTag> &&blocks0,
+		std::shared_ptr<const NBT::ByteArrayTag> &&data0
+	) : Section(section), blocks(blocks0), data(data0) {}
+
+	virtual const Resource::BlockType * getBlockStateAt(size_t x, size_t y, size_t z) const;
+};
+
+}
+}