127 lines
4.1 KiB
Markdown
127 lines
4.1 KiB
Markdown
First, establish some of the cell data
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```lisp
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; This will result in a "2x2" cell, of [0 1 1 1], with 0 representing an empty
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; space, and 1 representing a wall.
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(var (hall-width wall-width) (values 1 1))
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; This sets the "map width". This means 10 cells across and down. With each cell
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; being 2x2, this results in a 20x20 square map. All maps will be square (for
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; now).
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(var num-cells 10)
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; Explicitly setting cell-size for convenience. All cells are squares
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(var cell-size (+ hall-width wall-width))
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```
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Next, generate the initial array of cells to work with.
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```lisp
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(var cells {})
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(for [i 1 (* num-cells num-cells)]
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(table.insert cells {
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:n false :s false :e false :w false
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:v false
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:o false
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}))
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```
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`:n`, `:s`, `:e`, `:w` - if cell has a directional connection
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`:v` - has the cell been visited
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`:o` - does the cell contain an obstacle
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With the cells established, can use a recursive depth-first search with a stack
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to generate the maze.
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For ease, we'll always start along the top. Eventually, want to ensure the
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solution is along the sides or bottom.
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```lisp
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(var cell-stack [(math.random 1 num-cells)])
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(while (> 0 (length cell-stack)
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(var current-cell (table.remove cell-stack (length cell-stack)))
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(tset cells current-cell :v true)
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; Check if any of the current cell's neighbors are
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; 1. unvisited
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; 2. a side/barrier wall
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(var next-cells {})
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; North -
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; if current-cell <= num-cells, then north is a map-side/barrier
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(when (> num-cells current-cell)
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(var n-cell (- current-cell num-cells))
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(if (not (. cells n-cell :v)) (table.insert next-cells n-cell)))
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; South -
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; if current-cell > (- (* num-cells num-cells) num-cells),
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; then south is a map-side/barrier
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(when (< current-cell (- (* num-cells num-cells) num-cells))
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(var s-cell (- (* num-cells num-cells) num-cells))
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(if (not (. cells s-cell :v)) (table.insert next-cells s-cell)))
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; East -
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; if current-cell % num-cells = 0, then east is a map-side/barrier
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(when (not (= 0 (% current-cell num-cells)))
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(var e-cell (+ current-cell 1))
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(if (not (. cells e-cell :v)) (table.insert next-cells e-cell)))
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; West -
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; if current-cell % num-cells = 1, then west is a map-side/barrier
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(when (not (= 1 (% current-cell num-cells)))
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(var w-cell (- current-cell 1))
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(if (not (. cells e-cell :v)) (table.insert next-cells w-cell)))
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```
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---
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For output:
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Each cell is then used to generate values in the map array. Each cell will have
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either a hallway or a wall at each position, for `cell-size` positions.
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Iterate through each cell. Cells 1 through `num-cells` are the first row, then
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(1 + `num-cells`) through (`num-cells` * 2), and so on. This can be generalized
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and extrapolated to `(x + (num-cells * (y - 1)))` through `(num-cells * y)`, for
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`x` and `y` loops from 1 to `num-cells`.
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```lisp
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(for [i 1 num-cells]
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(for [j 1 num-cells]
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```
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Each cell is of uniform size, and the map is a square that divides evenly by
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that size. We established the width, and that value squared is the map. Every
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cell is numbered from 1 to `(* num-cells num-cells)` (ie., 1 to 100). The index
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of the cell divided by `num-cells`, plus 1, gets the row:
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```lisp
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(fn row [i] (+ 1 (// i num-cells)))
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```
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This gets the "upper-left" for the map array, given a cell index.
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```lisp
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(fn c [i] (+ (- (* i cell-size) 1) (* cell-size cell-num (- (row i) 1))))
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```
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Using that index, iterate through the cell based on `cell-size` twice, using
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each loop to add either `(- i 1)` and `(* (- j 1) cell-num)` to the value from
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`c` above, and insert it into the map array.
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---
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For cell generation:
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Each cell is a combination of hallways and walls. For each cell, if the "row" or
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"column" is less than the `hall-width`, enter a "0", otherwise enter a "1".
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```lisp
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(var cell [])
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(for [i 1 cell-size]
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(for [j 1 cell-size]
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(var cell-index (+ j (* (- i 1) cell-size)))
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(if (and (< i (+ hall-width 1)) (< j (+ hall-width 1)))
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(tset cell cell-index 0)
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(tset cell cell-index 1))))
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```
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