# mz_theta_cells

This function returns cell data of a theta maze. The data is a two-dimensional list with different row lengths. A cell has the data structure `[ri, ci, type]`. `ri` and `ci` are 0-based. `ri` means the ri-th ring and `ci` means the ci-th (counter-clockwise) cell of the ring. The value of `type` is the wall type of the cell. It can be `0`, `1`, `2` or `3`. Setting them to constants is convenient.

``````NO_WALL = 0;           // the cell has no wall
INWARD_WALL = 1;       // the cell has an inward wall
CCW_WALL = 2;          // the cell has a counter-clockwise wall
INWARD_CCW_WALL = 3;   // the cell has an inward wall and a clockwise wall
`````` Since: 3.0

## Parameters

• `rows` : The number of rings.
• `beginning_number` : The number of cells in the first row.
• `start` : The start point to travel the maze. Default to `[0, 0]`.
• `seed` : The maze is traveling randomly. Use `seed` to initialize the pseudorandom number generator.

## Examples

``````use <maze/mz_theta_cells.scad>;

rows = 8;
beginning_number = 8;
cell_width = 10;
wall_thickness = 2;

NO_WALL = 0;
INWARD_WALL = 1;
CCW_WALL = 2;
INWARD_CCW_WALL = 3;

function vt_from_angle(theta, r) = [r * cos(theta), r * sin(theta)];

maze = mz_theta_cells(rows, beginning_number);

// draw cell walls
for(rows = maze) {
for(cell = rows) {
ri = cell;
ci = cell;
type = cell;
thetaStep = 360 / len(maze[ri]);
innerR = (ri + 1) * cell_width;
outerR = (ri + 2) * cell_width;
theta1 = thetaStep * ci;
theta2 = thetaStep * (ci + 1);

innerVt1 = vt_from_angle(theta1, innerR);
innerVt2 = vt_from_angle(theta2, innerR);
outerVt2 = vt_from_angle(theta2, outerR);

if(type == INWARD_WALL || type == INWARD_CCW_WALL) {
hull_polyline2d([innerVt1, innerVt2], width = wall_thickness);
}

if(type == CCW_WALL || type == INWARD_CCW_WALL) {
hull_polyline2d([innerVt2, outerVt2], width = wall_thickness);
}
}
}

// outmost walls
thetaStep = 360 / len(maze[rows - 1]);
r = cell_width * (rows + 1);
for(theta = [0:thetaStep:360 - thetaStep]) {
vt1 = vt_from_angle(theta, r);
vt2 = vt_from_angle(theta + thetaStep, r);
hull_polyline2d([vt1, vt2], width = wall_thickness);
}
`````` 