fastmath.grid — generateme/fastmath 2.2.1

Grid calculation functions.

Convert 2d coordinates into various grid coordinates and back.

Terms used:

• cell type - grid cell shape: square, triangular, hexagonal, rhomboidal
• coords - 2d euclidean coordinates (x,y)
• cell - cell coordinates (q,r)
• anchor - cell position in 2d euclidean space
• corners - shape vertices
• size - size of the cell.

Grids

Each grid is defined by cell type and size. Optionally you can provide translating vector.

Each cell has it's own coordinates, mostly axial based (only square has offset).

For hexagonal cell size is a radius from midpoint to corner. For the rest it is the size of the side.

Cell types are:

• :square
• :shifted-square
• :triangle
• :rhombus
• :flat-hex - flat topped
• :pointy-hex - pointy topped

Notes

• Hexagonal grids are based on https://www.redblobgames.com/grids/hexagons/
• Only hexagonal cells have anchor at the center. For the rest the anchor is at the top left vertex.
  • Anchors for triangular grids are shared between two cells: even and odd q coordinate. Even q is pointy topped, odd q is flat topped which is marked in the third coordinate of anchor.

cell->anchor clj

(cell->anchor g cell)

(cell->anchor g q r)

Converts cell coordinates (q,r) to anchor coordinates (x,y).

cell->mid clj

(cell->mid g cell)

(cell->mid g x y)

Converts cell coordinates (q,r) to mid point (x,y).

cell-names clj

coords->anchor clj

(coords->anchor g coords)

(coords->anchor g x y)

Converts 2d coordinates (x,y) to cell anchor (x,y).

coords->cell clj

(coords->cell g coords)

(coords->cell g x y)

Converts 2d space coordinates (x,y) to cell coordinates (q,r).

coords->mid clj

(coords->mid g coords)

(coords->mid g x y)

Converts 2d space coordinates (x,y) into cell midpoint (x,y).

corners clj

(corners g coords)

(corners g coords scale)

(corners g x y scale)

Returns list of cell vertices for given 2d space coordinates.

flat-hex-corners clj

Function which returns vertices for flat topped hexagon for given size and coordinates.

grid clj

(grid)

(grid type)

(grid type size)

(grid type size sx sy)

Create grid for given type, size and optional translating vector.

grid-type clj

(grid-type g)

Returns type of the cell.

pointy-hex-corners clj

Function which returns vertices for pointy topped hexagon for given size and coordinates.