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#pragma once
#include <array>
#include <cassert>
#include <cstdint>
namespace kel {
namespace impl {
struct ico_surface_helper {
/**
* On each triangle we assume a ccw order and we start on the top-left part of the
* triangle. The orientation of the triangle is determined by the horizontal line
* (on the 2D foldout of the icosahedron) which is the down direction.
*/
static constexpr std::array<std::array<uint8_t,3u>, 20u> neighbour_map {{
{1,4,5},//0
{2,0,6},//1
{3,1,7},//2
{4,2,8},//3
{0,3,9},//4
{14,10,0},//5
{10,11,1},//6
{11,12,2},//7
{12,13,3},//8
{13,14,4},//9
{6,5,15},//10
{7,6,16},//11
{8,7,17},//12
{9,8,18},//13
{5,9,19},//14
{19,16,10},//15
{15,17,11},//16
{16,18,12},//17
{17,19,13},//18
{18,15,14} //19
}};
};
}
template<uint64_t SubD>
class ico_addr {
private:
std::array<uint8_t, SubD> vals_;
public:
uint8_t& at(uint64_t i){
return vals_[i];
}
const uint8_t& at(uint64_t i) const {
return vals_[i];
}
constexpr uint64_t size() const {
return SubD;
}
bool is_equal(const ico_addr<SubD>& rhs) const {
bool eq = true;
for(uint64_t i = 0u; i < size(); ++i){
eq &= (at(i) == rhs.at(i));
}
return eq;
}
bool has_zero() const {
uint64_t z_ctr = 0u;
for(uint64_t i = 1u; i < size(); ++i){
z_ctr += (at(i) == 0u ? 1u : 0u);
}
return (z_ctr > 0u);
}
std::array<uint64_t,4u> count_groups() const {
std::array<uint64_t,4u> grps{0,0,0,0};
for(uint64_t i = 1u; i < size(); ++i){
auto& addr_i = vals_[i];
assert(addr_i < 4);
++grps[addr_i];
}
return grps;
}
uint64_t count_non_zero_groups() const {
auto ctr = count_groups();
uint64_t grp_ctr = 0u;
for(uint64_t i = 1u; i < ctr.size(); ++i){
grp_ctr += (ctr[i] > 0u ? 1u : 0u);
}
return grp_ctr;
}
bool has_all_non_zero_groups() const {
auto ctr = count_non_zero_groups();
return (ctr == 3u);
}
ico_addr<SubD> go_to(uint8_t dir_i){
ico_addr<SubD> cpy_addr;
cpy_addr.vals_ = vals_;
if(at(size() - 1u) == 0u){
cpy_addr.at(size() - 1u) = dir_i + 1u;
}
if(at(size() - 1u) == (dir_i + 1u)){
cpy_addr.at(size() - 1u) = 0u;
}
return cpy_addr;
}
bool borders_root() const {
return not (has_all_non_zero_groups() or has_zero());
}
};
template<typename T, uint64_t D>
class ico_triangle {
private:
std::array<ico_triangle<T,D-1u>,4u> subdivs_;
public:
ico_triangle<T,D-1u>& at(uint8_t i){
return subdivs_[i];
}
template<uint64_t AddrOrigLen>
ico_triangle<T,0u> at(const ico_addr<AddrOrigLen>& addr, uint64_t next_i){
auto& addr_i = addr[next_i];
auto& sub_triangle = subdivs_[addr_i];
if constexpr ( D == 1u){
return sub_triangle;
}
return sub_triangle.at(addr,next_i+1u);
}
};
template<typename T>
class ico_triangle<T,0u> final {
private:
T val_;
public:
};
namespace impl {
}
template<typename T, uint64_t SubD>
class icosahedron final {
private:
std::array<ico_triangle<T,SubD>,20u> surfaces_;
public:
template<uint64_t AddrD>
ico_triangle<T,SubD+1u-AddrD> at(const ico_addr<AddrD>& addr){
static_assert(AddrD <= (SubD+1u), "Addr length to large.");
static_assert(AddrD > 0u, "Addr length to small.");
auto& root_addr = addr[0u];
auto& root_triangle = surfaces_[root_addr];
return root_triangle.at(addr, 1u);
}
};
}
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