From 83cb0653209f3300e220e76d3f57a000ef4219a6 Mon Sep 17 00:00:00 2001
From: Elizabeth Hunt <me@liz.coffee>
Date: Sun, 25 Jan 2026 21:01:28 -0800
Subject: Make life grid a torus and vastly simplify audio 'visualization'

---
 core/src/main/java/coffee/liz/ecs/math/Mat2.java | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

(limited to 'core/src/main/java/coffee/liz/ecs')

diff --git a/core/src/main/java/coffee/liz/ecs/math/Mat2.java b/core/src/main/java/coffee/liz/ecs/math/Mat2.java
index 8be945c..9975227 100644
--- a/core/src/main/java/coffee/liz/ecs/math/Mat2.java
+++ b/core/src/main/java/coffee/liz/ecs/math/Mat2.java
@@ -31,7 +31,8 @@ public final class Mat2 {
 	}
 
 	/**
-	 * Convolves a {@link Convolver} across a matrix.
+	 * Convolves a {@link Convolver} across a matrix reaching neighbors around the
+	 * grid like a torus.
 	 *
 	 * @param mat
 	 *            is the row-indexed 2d matrix to convolve.
@@ -49,7 +50,7 @@ public final class Mat2 {
 	 * @param <R>
 	 *            is the type of the resulting type of each convolution.
 	 */
-	public static <T, R, U> List<List<U>> convolve(final List<List<T>> mat, final Vec2<Integer> axes,
+	public static <T, R, U> List<List<U>> convolveTorus(final List<List<T>> mat, final Vec2<Integer> axes,
 			final Supplier<R> init, final Convolver<T, R> convolver, final BiFunction<T, R, U> finalReduction) {
 		final List<List<R>> rows = new ArrayList<>();
 		for (int y = 0; y < mat.size(); y++) {
@@ -58,13 +59,9 @@ public final class Mat2 {
 				final T center = mat.get(y).get(x);
 				R result = init.get();
 				for (int dy = -axes.getY(); dy <= axes.getY(); dy++) {
-					final int ry = y + dy;
-					if (ry < 0 || ry >= mat.size())
-						continue;
+					final int ry = Math.floorMod(y + dy, mat.size());
 					for (int dx = -axes.getX(); dx <= axes.getX(); dx++) {
-						final int rx = x + dx;
-						if (rx < 0 || rx >= mat.get(ry).size())
-							continue;
+						final int rx = Math.floorMod(x + dx, mat.get(ry).size());
 						result = convolver.convolve(mat.get(ry).get(rx), Vec2i.builder().x(dx).y(dy).build(), result);
 					}
 				}
-- 
cgit v1.2.3-70-g09d2