project-swan/libswan/include/swan/Chunk.h

#pragma once

#include <string.h>
#include <stdint.h>
#include <memory>

#include "util.h"
#include "common.h"
#include "Tile.h"

namespace Swan {

class World;
class Game;

class Chunk {
public:
	using RelPos = TilePos;

	static constexpr size_t DATA_SIZE =
		CHUNK_WIDTH * CHUNK_HEIGHT * sizeof(Tile::ID) + // Tiles
		CHUNK_WIDTH * CHUNK_HEIGHT; // Light levels

	// What does this chunk want the world gen to do after a tick?
	enum class TickAction {
		DEACTIVATE,
		DELETE,
		NOTHING,
	};

	Chunk(ChunkPos pos): pos_(pos) {
		data_.reset(new uint8_t[DATA_SIZE]);
		memset(getLightData(), 0, CHUNK_WIDTH * CHUNK_HEIGHT);
	}

	Tile::ID *getTileData() {
		assert(isActive());
		return (Tile::ID *)data_.get();
	}

	uint8_t *getLightData() {
		assert(isActive());
		return data_.get() + CHUNK_WIDTH * CHUNK_HEIGHT * sizeof(Tile::ID);
	}

	Tile::ID getTileID(RelPos pos) {
		return getTileData()[pos.y * CHUNK_WIDTH + pos.x];
	}

	void setTileID(RelPos pos, Tile::ID id, SDL_Texture *tex) {
		getTileData()[pos.y * CHUNK_WIDTH + pos.x] = id;
		drawList_.push_back({ pos, tex });
	}

	void setTileData(RelPos pos, Tile::ID id) {
		getTileData()[pos.y * CHUNK_WIDTH + pos.x] = id;
		needRender_ = true;
	}

	uint8_t getLightLevel(RelPos pos) {
		return getLightData()[pos.y * CHUNK_WIDTH + pos.x];
	}

	void setLightData(const uint8_t *data) {
		memcpy(getLightData(), data, CHUNK_WIDTH * CHUNK_HEIGHT);
		needLightRender_ = true;
	}

	void render(const Context &ctx, SDL_Renderer *rnd);
	void renderLight(const Context &ctx, SDL_Renderer *rnd);

	void compress();
	void decompress();
	void draw(const Context &ctx, Win &win);
	TickAction tick(float dt);

	bool isActive() { return deactivateTimer_ > 0; }
	void keepActive();
	void markModified() { isModified_ = true; }

	ChunkPos pos_;

private:
	static constexpr float DEACTIVATE_INTERVAL = 20;

	void renderList(SDL_Renderer *rnd);

	bool isCompressed() { return compressedSize_ != -1; }

	std::unique_ptr<uint8_t[]> data_;
	std::vector<std::pair<RelPos, SDL_Texture *>> drawList_;

	ssize_t compressedSize_ = -1; // -1 if not compressed, a positive number if compressed
	bool needRender_ = false;
	bool needLightRender_ = false;
	float deactivateTimer_ = DEACTIVATE_INTERVAL;
	bool isModified_ = false;

	CPtr<SDL_Texture, SDL_DestroyTexture> texture_;
	CPtr<SDL_Texture, SDL_DestroyTexture> lightTexture_;
};

}