From 308aacc1e6511ec8ed19a62e056f298b1be0c9d9 Mon Sep 17 00:00:00 2001
From: techmetx11 <techmetx11@disroot.org>
Date: Wed, 19 Feb 2025 14:01:11 +0100
Subject: [PATCH] Implement looping in TFM import

---
 src/engine/fileOps/tfm.cpp | 42 ++++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/src/engine/fileOps/tfm.cpp b/src/engine/fileOps/tfm.cpp
index 919e7f52f..6b0365346 100644
--- a/src/engine/fileOps/tfm.cpp
+++ b/src/engine/fileOps/tfm.cpp
@@ -193,6 +193,7 @@ struct TFMParsePatternInfo {
   DivSong* ds;
   int* insNumMaps;
   bool v2;
+  unsigned char loop_pos;
 };
 
 void TFMParsePattern(struct TFMParsePatternInfo info) {
@@ -366,7 +367,7 @@ void TFMParsePattern(struct TFMParsePatternInfo info) {
             pat->data[k][5+(l*2)]=effectVal[k];
             break;
           case 13:
-            // modify TL of operator 2
+            // modify TL of operator 4
             pat->data[k][4+(l*2)]=0x15;
             pat->data[k][5+(l*2)]=effectVal[k];
             break;
@@ -459,17 +460,21 @@ void TFMParsePattern(struct TFMParsePatternInfo info) {
   bool chVibrato[6]={false};
   bool chPorta[6]={false};
   bool chVolumeSlide[6]={false};
+  int lastPatSeen=0;
 
   for (int i=0; i<info.ds->subsong[0]->ordersLen; i++) {
+    // this is if the last pattern is used more than once
+    if (info.orderList[i] == info.orderList[info.ds->subsong[0]->ordersLen - 1]) {
+      lastPatSeen++;
+    }
     for (int j=0; j<6; j++) {
       for (int l=0; l<usedEffectsCol; l++) {
         DivPattern* pat = info.ds->subsong[0]->pat[j].data[info.orderList[i]];
+        unsigned char truePatLen=(info.patLens[info.orderList[i]]<info.ds->subsong[0]->patLen) ? info.patLens[info.orderList[i]] : info.ds->subsong[0]->patLen;
 
         // default instrument
         if (i==0 && pat->data[0][2]==-1) pat->data[0][2]=0;
 
-        unsigned char truePatLen=(info.patLens[info.orderList[i]]<info.ds->subsong[0]->patLen) ? info.patLens[info.orderList[i]] : info.ds->subsong[0]->patLen;
-
         for (int k=0; k<truePatLen; k++) {
           if (chArpeggio[j] && pat->data[k][4+(l*2)]!=0x00 && pat->data[k][0]!=-1) {
             pat->data[k][4+usedEffectsCol*2+(l*2)]=0x00;
@@ -505,12 +510,35 @@ void TFMParsePattern(struct TFMParsePatternInfo info) {
             chVolumeSlide[j]=true;
             break;
           default:
-            break;
+    break;
           }
         }
       }
     }
   }
+
+  if (lastPatSeen>1) {
+    // clone the last pattern 
+    info.maxPat++;
+    for (int i=0;i<6;i++) {
+      int last_pat_num = info.ds->subsong[0]->orders.ord[i][info.ds->subsong[0]->ordersLen - 1];
+      DivPattern* new_pat = new DivPattern;
+      DivPattern* last_pat = info.ds->subsong[0]->pat[i].data[last_pat_num];
+      last_pat->copyOn(new_pat);
+
+      info.ds->subsong[0]->orders.ord[i][info.ds->subsong[0]->ordersLen - 1] = info.maxPat;
+      new_pat->data[info.patLens[last_pat_num]-1][4+(usedEffectsCol*4)] = 0x0B;
+      new_pat->data[info.patLens[last_pat_num]-1][5+(usedEffectsCol*4)] = info.loop_pos;
+      info.ds->subsong[0]->pat[i].data[info.maxPat] = new_pat;
+    }
+  } else {
+    for (int i=0;i<6;i++) {
+      int last_pat_num = info.ds->subsong[0]->orders.ord[i][info.ds->subsong[0]->ordersLen - 1];
+      DivPattern* last_pat = info.ds->subsong[0]->pat[i].data[last_pat_num];
+      last_pat->data[info.patLens[last_pat_num]-1][4+(usedEffectsCol*4)] = 0x0B;
+      last_pat->data[info.patLens[last_pat_num]-1][5+(usedEffectsCol*4)] = info.loop_pos;
+    }
+  }
 }
 
 bool DivEngine::loadTFMv1(unsigned char* file, size_t len) {
@@ -551,7 +579,7 @@ bool DivEngine::loadTFMv1(unsigned char* file, size_t len) {
     ds.subsong[0]->ordersLen=reader.readCNoRLE();
 
     // order loop position, unused
-    (void)reader.readCNoRLE();
+    unsigned char loop_pos = reader.readCNoRLE();
 
     ds.createdDate=TFMparseDate(reader.readSNoRLE());
     ds.revisionDate=TFMparseDate(reader.readSNoRLE());
@@ -677,6 +705,7 @@ bool DivEngine::loadTFMv1(unsigned char* file, size_t len) {
     info.patLens=patLens;
     info.reader=&reader;
     info.v2=false;
+    info.loop_pos=loop_pos;
     TFMParsePattern(info);
 
     if (active) quitDispatch();
@@ -750,7 +779,7 @@ bool DivEngine::loadTFMv2(unsigned char* file, size_t len) {
     ds.subsong[0]->ordersLen=reader.readCNoRLE();
 
     // order loop position, unused
-    (void)reader.readCNoRLE();
+    unsigned char loop_pos = reader.readCNoRLE();
 
     ds.createdDate=TFMparseDate(reader.readSNoRLE());
     ds.revisionDate=TFMparseDate(reader.readSNoRLE());
@@ -876,6 +905,7 @@ bool DivEngine::loadTFMv2(unsigned char* file, size_t len) {
     info.patLens=patLens;
     info.reader=&reader;
     info.v2=true;
+    info.loop_pos=loop_pos;
     TFMParsePattern(info);
 
     if (active) quitDispatch();