Fill: plant nothing for a region that misses the object entirely

clampTo INVERTS a region lying wholly outside the object — Max clamps below Min — rather than emptying it. The old loop-until-past-MaxX form handled that for free by never entering the loop. Counting positions up front does not: a region 500cm east of a bed with ±50cm local bounds produced 4 plops at x=275, a couple of metres off the bed. Caught by removing the guard and watching the new test fail, not by assuming it would. Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]> Claude-Session: https://claude.ai/code/session_01H3zbym8Doka2d7D48maSgZ
2026-07-21 10:13:33 -04:00
parent 45da4b15e2
commit 3af0d08779
2 changed files with 28 additions and 0 deletions
@@ -195,6 +195,13 @@ func hexCenters(r Region, radius, spacing float64) []localPoint {
 	if radius <= 0 {
 		return nil
 	}
+	// clampTo INVERTS a region that lies wholly outside the object (Max clamps
+	// below Min), and an inverted region has no inside to plant. The old
+	// loop-until-past-MaxX form got this for free by never entering the loop;
+	// counting positions up front does not, and would site a plop off the bed.
+	if r.MaxX < r.MinX || r.MaxY < r.MinY {
+		return nil
+	}
 	pitch := 2 * radius
 	rowH := pitch * math.Sqrt(3) / 2