voxel-raycaster/include/Map.h

#pragma once
#include <SFML/System/Vector3.hpp>
#include <SFML/System/Vector2.hpp>
#include <SFML/Graphics/Color.hpp>
#include <iostream>
#include <list>
#include <random>
#include <iostream>
#include <functional>
#include <cmath>
#include <deque>
#include <unordered_map>
#include <bitset>
#include <cstring>
#include <queue>
#include "util.hpp"

#define _USE_MATH_DEFINES
#include <math.h>

#define CHUNK_DIM 32
#define OCT_DIM 8

struct XYZHasher {
	std::size_t operator()(const sf::Vector3i& k) const {
		return ((std::hash<int>()(k.x)
			^ (std::hash<int>()(k.y) << 1)) >> 1)
			^ (std::hash<int>()(k.z) << 1);
	}
};

class Octree {
public:
	Octree() {

		// initialize the first stack block
		block_stack.push_back(new uint64_t[0x8000]);
		for (int i = 0; i < 0x8000; i++) {
			block_stack.back()[i] = 0;
		}


	};

	~Octree() {};

	std::list<uint64_t*> block_stack;
	uint64_t stack_pos = 0x8000;
	uint64_t global_pos = 0;
	
	uint64_t copy_to_stack(std::vector<uint64_t> children) {
		
		// Check for the 15 bit boundry		
		if (stack_pos - children.size() > stack_pos) {
			global_pos = stack_pos;
			stack_pos = 0x8000;
		}
		else {
			stack_pos -= children.size();
		}

		// Check for the far bit

		memcpy(&block_stack.front()[stack_pos + global_pos], children.data(), children.size() * sizeof(uint64_t));
		
		// Return the bitmask encoding the index of that value
		// If we tripped the far bit, allocate a far index to the stack and place
		// it one above preferably.
		// And then shift the far bit to 1

		// If not, shift the index to its correct place
		return stack_pos;
	};


	int get_idx(sf::Vector3i voxel_pos) {
	
		return 1;
		
	}

	// (X, Y, Z) mask for the idx
	uint8_t idx_set_x_mask = 0x1;
	uint8_t idx_set_y_mask = 0x2;
	uint8_t idx_set_z_mask = 0x4;

	// Mask for 
	uint8_t mask_8[8] = {
		0x1,  0x2,  0x4,  0x8,
		0x10, 0x20, 0x40, 0x80
	};

	uint8_t count_mask_8[8]{
		0x1,  0x3,  0x7,  0xF,
		0x1F, 0x3F, 0x7F, 0xFF
	};

	//uint8_t count_mask_8[8]{
	//	0xFF, 0x7F, 0x3F, 0x1F,
	//	0xF,  0x7,  0x3,  0x1
	//};


	// With a position and the head of the stack. Traverse down the voxel hierarchy to find
	// the IDX and stack position of the highest resolution (maybe set resolution?) oct
	bool get_voxel(sf::Vector3i position) {

		// Init the parent stack 
		int parent_stack_position = 0;
		uint64_t parent_stack[32] = {0};
		
		// and push the head node
		uint64_t head = block_stack.front()[stack_pos];
		parent_stack[parent_stack_position] = head;
		
		// Get the index of the first child of the head node
		uint64_t index = head & child_pointer_mask;

		// Init the idx stack
		uint8_t scale = 0;
		uint8_t idx_stack[32] = {0};

		// Init the idx stack (DEBUG)
		std::vector<std::bitset<3>> scale_stack(static_cast<uint64_t>(log2(OCT_DIM)));

		// Set our initial dimension and the position at the corner of the oct to keep track of our position
		int dimension = OCT_DIM;
		sf::Vector3i quad_position(0, 0, 0);

		// While we are not at the required resolution
		//		Traverse down by setting the valid/leaf mask to the subvoxel
		//		Check to see if it is valid
		//			Yes? 
		//				Check to see if it is a leaf
        //				No? Break
		//				Yes? Scale down to the next hierarchy, push the parent to the stack
		//		
		//			No?
		//				Break
		while (dimension > 1) {
			
			// So we can be a little bit tricky here and increment our
			// array index that holds our masks as we build the idx. 
			// Adding 1 for X, 2 for Y, and 4 for Z
			int mask_index = 0;


			// Do the logic steps to find which sub oct we step down into
			if (position.x >= (dimension / 2) + quad_position.x) {

				// Set our voxel position to the (0,0) of the correct oct
				quad_position.x += (dimension / 2);

				// increment the mask index and mentioned above
				mask_index += 1;

				// Set the idx to represent the move
				idx_stack[scale] |= idx_set_x_mask;

				// Debug
				scale_stack.at(static_cast<uint64_t>(log2(OCT_DIM) - log2(dimension))).set(0);
				
			}
			if (position.y >= (dimension / 2) + quad_position.y) {

				quad_position.y |= (dimension / 2);

				mask_index += 2;

				idx_stack[scale] ^= idx_set_y_mask;
				scale_stack.at(static_cast<uint64_t>(log2(OCT_DIM) - log2(dimension))).set(1);
			}
			if (position.z >= (dimension / 2) + quad_position.z) {

				quad_position.z += (dimension / 2);

				mask_index += 4;
				
				idx_stack[scale] |= idx_set_z_mask;
				scale_stack.at(static_cast<uint64_t>(log2(OCT_DIM) - log2(dimension))).set(2);
			}

			uint64_t out1 = (head >> 16) & mask_8[mask_index];
			uint64_t out2 = (head >> 24) & mask_8[mask_index];

			// Check to see if we are on a valid oct
			if ((head >> 16) & mask_8[mask_index]) {
				
				// Check to see if it is a leaf
				if ((head >> 24) & mask_8[mask_index]) {

					// If it is, then we cannot traverse further as CP's won't have been generated
					return true;
					break;
				}

				// If all went well and we found a valid non-leaf oct then we will traverse further down the hierarchy
				scale++;
				dimension /= 2;

				// We also need to traverse to the correct child pointer
				
				// Count the number of non-leaf octs that come before and add it to the index to get the position
				int i1 = count_bits((uint8_t)(head >> 16) & count_mask_8[0]);
				int i2 = count_bits((uint8_t)(head >> 16) & count_mask_8[1]);
				int i3 = count_bits((uint8_t)(head >> 16) & count_mask_8[2]);
				int i4 = count_bits((uint8_t)(head >> 16) & count_mask_8[3]);
				int i5 = count_bits((uint8_t)(head >> 16) & count_mask_8[4]);
				int i6 = count_bits((uint8_t)(head >> 16) & count_mask_8[5]);
				int i7 = count_bits((uint8_t)(head >> 16) & count_mask_8[6]);
				int i8 = count_bits((uint8_t)(head >> 16) & count_mask_8[7]);

				int count = count_bits((uint8_t)(head >> 16) & count_mask_8[mask_index]);

				// Because we are getting the position at the first child we need to back up one
				// Or maybe it's because my count bits function is wrong...
				index = (head & child_pointer_mask) + count - 1;
				head = block_stack.front()[index];

				// Increment the parent stack position and put the new oct node as the parent
				parent_stack_position++;
				parent_stack[parent_stack_position] = block_stack.front()[index];
			
			} else {
				// If the oct was not valid, then no CP's exists any further
				// This implicitly says that if it's non-valid then it must be a leaf!!

				// It appears that the traversal is now working but I need
				// to focus on how to now take care of the end condition.
				// Currently it adds the last parent on the second to lowest
				// oct CP. Not sure if thats correct
				return false;
				break;
			}
		}


        std::bitset<64> t(index);
        auto val = t.count();

		return true;
	}


	void print_block(int block_pos) {
		std::stringstream sss;
		for (int i = 0; i < (int)pow(2, 15); i++) {
			PrettyPrintUINT64(block_stack.front()[i], &sss);
			sss << "\n";
		}
		DumpLog(&sss, "raw_data.txt");
	}

private:

	const uint64_t child_pointer_mask = 0x0000000000007fff;
	const uint64_t far_bit_mask = 0x8000;
	const uint64_t valid_mask = 0xFF0000;
	const uint64_t leaf_mask = 0xFF000000;
	const uint64_t contour_pointer_mask = 0xFFFFFF00000000;
	const uint64_t contour_mask = 0xFF00000000000000;

};


class Map {
public: 

	
	Map(sf::Vector3i position);
	void generate_octree();

	void load_unload(sf::Vector3i world_position);
	void load_single(sf::Vector3i world_position);

	sf::Vector3i getDimensions();
	char *list;
	//sf::Vector3i dimensions;

	void setVoxel(sf::Vector3i position, int val);

	char getVoxelFromOctree(sf::Vector3i position);

	bool getVoxel(sf::Vector3i pos);
	Octree a;

	sf::Vector3f global_light;

	void test_map();

protected:

private:

	// DEBUG
	int counter = 0;
	std::stringstream output_stream;

	// !DEBUG


	uint64_t generate_children(sf::Vector3i pos, int dim);


	char* voxel_data = new char[OCT_DIM * OCT_DIM * OCT_DIM];

	//std::unordered_map<sf::Vector3i, Chunk, XYZHasher> chunk_map;

	double* height_map;

	// 2^k
	int chunk_radius = 6;

	sf::Vector3i world_to_chunk(sf::Vector3i world_coords) {
		return sf::Vector3i(
			world_coords.x / CHUNK_DIM + 1,
			world_coords.y / CHUNK_DIM + 1,
			world_coords.z / CHUNK_DIM + 1
			);
	}
};