I was highly inspired by this article: https://www.redblobgames.com/grids/hexagons/ and this repo is mostly just C# implementation of it. Recommended for reading. Here I will describe some technical details regarding implementation.

To use hexagonal grids you need to create HexagonalGrid and initialize it with grid type and inscribed radius of hex.

var grid = new HexagonalGrid(HexagonalGridType.PointyEven, 1.0f);

Grids layouts and orientations are merged to one enum HexagonalGridType.

• PointyOdd - Horizontal layout shoves odd rows right [odd-r]
• PointyEven - Horizontal layout shoves even rows right [even-r]
• FlatOdd - Vertical layout shoves odd columns down [odd-q]
• FlatEven - Vertical layout shoves even columns down [even-q]

There is three coordinates systems represented in lib:

• Offset - offset coordinates (link)
• Cubic - cube coordinates (link)
• Axial - axial coordinates (link)

Note: there is no Doubled coordinates yet. I will add them in later versions.

Struct HexagonalGrid contains a bunch of methods for coordinates conversion (all details are described in original article):

var offsetFromCubic = grid.ToOffset(cubic);
var offsetFromAxial = grid.ToOffset(axial);
 
var cubicFromOffset = grid.ToCubic(offset);
var cubicFromAxial = grid.ToCubic(axial);
 
var axialFromOffset = grid.ToAxial(offset);
var axialFromCubic = grid.ToAxial(cubic);

There is the order of neighbors of hex:

You can take a neighbor of any hex by providing a coordinate of hex and required neighbor index.

var oNeighbor = grid.GetNeighbor(offset, neighborIndex);
var cNeighbor = grid.GetNeighbor(cubic, neighborIndex);
var aNeighbor = grid.GetNeighbor(axial, neighborIndex);

The neighbor index can be negative or greater than 5 (it will be normalized)

Or you can take all neighbors of particular hex

var oNeighbors = grid.GetNeighbors(offset);
var cNeighbors = grid.GetNeighbors(cubic);
var aNeighbors = grid.GetNeighbors(axial);

There is also option to check are two hexes neighbors or not:

var isNeighbors1 = grid.IsNeighbors(offset, oNeighbor);
var isNeighbors2 = grid.IsNeighbors(cubic, cNeighbor);
var isNeighbors3 = grid.IsNeighbors(axial, aNeighbor);

You also can get ring of neighbor for particular hex

var oNeighbors = grid.GetNeighborsRing(offset, radius);
var cNeighbors = grid.GetNeighborsRing(cubic, radius);
var aNeighbors = grid.GetNeighborsRing(axial, radius);

Same as ring but you will receive hexes from all rings

var oNeighbors = grid.GetNeighborsAround(offset, radius);
var cNeighbors = grid.GetNeighborsAround(cubic, radius);
var aNeighbors = grid.GetNeighborsAround(axial, radius);

There is also list of methods to convert hex coordinate to its center (point represented as tuple):

var pointFromOffset = grid.ToPoint2(offset);
var pointFromCubic = grid.ToPoint2(cubic);
var pointFromAxial = grid.ToPoint2(axial);

To convert point into a hex coordinate which contains this point you can use:

var offsetFromPoint = grid.ToOffset(x, y);
var cubicFromPoint = grid.ToCubic(x, y);
var axialFromPoint = grid.ToAxial(x, y);

Hexagons have 6 sides and 6 corners. There is corners order of the hexes:

To take them in code simly use:

var cornerFromOffset = grid.GetCorner(offset, cornerIndex);
var cornerFromCubic = grid.GetCorner(cubic, cornerIndex);
var cornerFromAxial = grid.GetCorner(axial, cornerIndex);

The corner index can be negative or greater than 5 (it will be normalized)