Add maze pkg

pkg/maze/generate.go

@@ -0,0 +1,84 @@
+package maze
+
+import (
+	"code.chimeric.al/dwrz/minotaur/pkg/maze/cell"
+	"code.chimeric.al/dwrz/minotaur/pkg/maze/direction"
+	"code.chimeric.al/dwrz/minotaur/pkg/maze/position"
+)
+
+func inBounds(h, w, x, y int) bool {
+	if x < 0 || x >= w {
+		return false
+	}
+	if y < 0 || y >= h {
+		return false
+	}
+
+	return true
+}
+
+// http://weblog.jamisbuck.org/2011/1/27/maze-generation-growing-tree-algorithm
+func generate(h, w int) [][]cell.Cell {
+	var layout = make([][]cell.Cell, h)
+
+	// Create the rows.
+	for i := range layout {
+		layout[i] = make([]cell.Cell, w)
+		for j := range layout[i] {
+			layout[i][j] = 0
+		}
+	}
+
+	// Connect the cells.
+	var (
+		current = position.Position{X: 0, Y: 0}
+		stack   = []position.Position{current}
+		visited = map[position.Position]struct{}{
+			current: {},
+		}
+	)
+	for len(stack) > 0 {
+		// Get newest.
+		current = stack[len(stack)-1]
+
+		dirs := direction.RandomDirections()
+		found := false
+		for _, d := range dirs {
+			var neighbor = current.WithDirection(d)
+
+			// Ignore if out of bounds.
+			if !inBounds(h, w, neighbor.X, neighbor.Y) {
+				continue
+			}
+
+			// Ignore if already visited.
+			if _, seen := visited[neighbor]; seen {
+				continue
+			}
+
+			// We've found a cell to connect.
+			found = true
+
+			// Mark it as visited.
+			visited[neighbor] = struct{}{}
+
+			// Add it to the queue.
+			stack = append(stack, neighbor)
+
+			// Connect the cells.
+			layout[current.Y][current.X].SetDirection(d)
+			layout[neighbor.Y][neighbor.X].SetDirection(
+				d.Opposite(),
+			)
+
+			break
+		}
+
+		// If no neighbor was found, remove this cell from the list.
+		if !found {
+			stack = stack[:len(stack)-1]
+		}
+	}
+
+	return layout
+}