From c5b16dd0511997331b8cc8c3647fff95effbe8ec Mon Sep 17 00:00:00 2001
From: Arne Dußin
Date: Fri, 30 Oct 2020 23:28:40 +0100
Subject: Snap rooms to the grid

---
 src/math.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'src/math.rs')

diff --git a/src/math.rs b/src/math.rs
index c4e7ac0..60a53e8 100644
--- a/src/math.rs
+++ b/src/math.rs
@@ -16,3 +16,21 @@ pub fn bounding_rect(pos1: Vector2, pos2: Vector2) -> Rectangle {
         height: max_y - min_y,
     }
 }
+
+/// Round a floating point number to the nearest step given by the step argument. For instance, if
+/// the step is 0.5, then all numbers from 0.0 to 0.24999... will be 0., while all numbers from
+/// 0.25 to 0.74999... will be 0.5 and so on.
+pub fn round(num: f32, step: f32) -> f32 {
+    // Only positive steps will be accepted.
+    assert!(step > 0.);
+
+    let lower_bound = ((num / step) as i32) as f32 * step;
+    let upper_bound = lower_bound + step;
+
+    // Compare the distances and prefer the smaller. If they are the same, prefer the upper bound.
+    if (num - lower_bound) < (upper_bound - num) {
+        lower_bound
+    } else {
+        upper_bound
+    }
+}
-- 
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