Grid helper.

Info:

• Copyright: 2014 Enrique García Cota, 2020 Atom-TM
• Author: Abelidze, oniietzschan, Enrique García Cota

Functions

Grid:toWorld(cellsize, cx, cy, cz)	Get left-top corner cell coordinates.
Grid:toCell(cellsize, x, y, z)	Convert left-top corner cell coordinates to cell indexes.
Grid:toCellCube(cellsize, x, y, z, w, h, d)	Convert cube from world to cell coordinates.
Grid:traverse(cellsize, x1, y1, z1, x2, y2, z2, f)	Function is based on "A Fast Voxel Traversal Algorithm for Ray Tracing", by John Amanides and Andrew Woo - http://www.cse.yorku.ca/~amana/research/grid.pdf It has been modified to include both cells when the ray "touches a grid corner", and with a different exit condition.

Functions

Methods

Grid:toWorld(cellsize, cx, cy, cz)

Get left-top corner cell coordinates.

Parameters:

• cellsize number Size of the cell in pixels.
• cx number Cell X index.
• cy number Cell Y index.
• cz number Cell Z index.

Returns:

1. number X coordinate.
2. number Y coordinate.
3. number Z coordinate.

Grid:toCell(cellsize, x, y, z)

Convert left-top corner cell coordinates to cell indexes.

Parameters:

• cellsize number Size of the cell in pixels.
• x number X coordinate.
• y number Y coordinate.
• z number Z coordinate.

Returns:

1. number Cell X index.
2. number Cell Y index.
3. number Cell Z index.

Grid:toCellCube(cellsize, x, y, z, w, h, d)

Convert cube from world to cell coordinates.

Parameters:

• cellsize number Size of the cell in pixels.
• x number Cube X coordinate.
• y number Cube Y coordinate.
• z number Cube Z coordinate.
• w number Cube width.
• h number Cube height.
• d number Cube depth.

Returns:

1. number Cell X index.
2. number Cell Y index.
3. number Cell Z index.
4. number Cell width.
5. number Cell height.
6. number Cell depth.

Grid:traverse(cellsize, x1, y1, z1, x2, y2, z2, f)

Function is based on "A Fast Voxel Traversal Algorithm for Ray Tracing", by John Amanides and Andrew Woo - http://www.cse.yorku.ca/~amana/research/grid.pdf It has been modified to include both cells when the ray "touches a grid corner", and with a different exit condition.

Parameters:

• cellsize number Size of the cell in pixels.
• x1 number Start X coordinate.
• y1 number Start Y coordinate.
• z1 number Start Z coordinate.
• x2 number End X coordinate.
• y2 number End Y coordinate.
• z2 number End Z coordinate.
• f function Traverse function called for each cell in path.