From c64a0f51c404c0558381f26657ac5ffbc15c5345 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Thu, 25 Apr 2024 17:59:56 -0500
Subject: [PATCH] implement "make patterns unique"

---
 src/engine/song.cpp | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/src/engine/song.cpp b/src/engine/song.cpp
index 8330f8f89..8e4b971ef 100644
--- a/src/engine/song.cpp
+++ b/src/engine/song.cpp
@@ -61,6 +61,37 @@ void DivSubSong::sortOrders() {
 }
 
 void DivSubSong::makePatUnique() {
+  for (int i=0; i<DIV_MAX_CHANS; i++) {
+    logD("making channel %d unique...",i);
+    bool seen[DIV_MAX_PATTERNS];
+    bool used[DIV_MAX_PATTERNS];
+
+    memset(seen,0,DIV_MAX_PATTERNS*sizeof(bool));
+    memset(used,0,DIV_MAX_PATTERNS*sizeof(bool));
+
+    // 1. populate used patterns
+    for (int j=0; j<ordersLen; j++) {
+      used[orders.ord[i][j]]=true;
+    }
+
+    // 2. make patterns unique
+    for (int j=0; j<ordersLen; j++) {
+      if (seen[orders.ord[i][j]]) {
+        for (int k=0; k<DIV_MAX_PATTERNS; k++) {
+          if (!used[k]) {
+            // copy here
+            DivPattern* dest=pat[i].getPattern(k,true);
+            DivPattern* src=pat[i].getPattern(orders.ord[i][j],false);
+            src->copyOn(dest);
+            orders.ord[i][j]=k;
+            break;
+          }
+        }
+      } else {
+        seen[orders.ord[i][j]]=true;
+      }
+    }
+  }
 }
 
 void DivSong::clearSongData() {