From 6acdf43bc056ed8c4c09508d700f4ff24934c920 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fischer@muhq.space>
Date: Thu, 12 Jan 2023 20:58:14 +0100
Subject: implement unit movement

---
 go/game/range.go | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 go/game/range.go

(limited to 'go/game/range.go')

diff --git a/go/game/range.go b/go/game/range.go
new file mode 100644
index 00000000..86ec2f50
--- /dev/null
+++ b/go/game/range.go
@@ -0,0 +1,39 @@
+package game
+
+import (
+	"math"
+)
+
+func IsPositionInRange(origin Position, pos Position, r int) bool {
+	x, y := float64(pos.X-origin.X), float64(pos.Y-origin.Y)
+	ax, ay := math.Abs(x), math.Abs(y)
+	var abs float64
+	if pos.X > pos.Y {
+		abs = ax + math.Floor(ay/2)
+	} else {
+		abs = ay + math.Floor(ax/2)
+	}
+
+	return abs <= float64(r)
+}
+
+func PositionsInRange(origin Position, r int, includeOrigin bool) []Position {
+	positions := []Position{}
+	for x := -r; x <= r; x++ {
+		for y := -r; y <= r; y++ {
+			pos := Position{origin.X + x, origin.Y + y}
+			if pos.X < 0 || pos.Y < 0 {
+				continue
+			}
+
+			if !includeOrigin && pos == origin {
+				continue
+			}
+
+			if IsPositionInRange(origin, pos, r) {
+				positions = append(positions, pos)
+			}
+		}
+	}
+	return positions
+}
-- 
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