From f75ab6186d525ffff30b2391d4c8515f3ba714ab Mon Sep 17 00:00:00 2001
From: techmetx11 <techmetx11@disroot.org>
Date: Thu, 11 Apr 2024 22:43:53 +0000
Subject: [PATCH] Partially implement TFM's effects

Fix the mismatched patterns hack to be more seamless, by adding the
"jump to next pattern" effects in the last row, in addition to the row
after that
---
 src/engine/fileOps/tfm.cpp | 52 +++++++++++++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 7 deletions(-)

diff --git a/src/engine/fileOps/tfm.cpp b/src/engine/fileOps/tfm.cpp
index 7572afee2..6fadee58e 100644
--- a/src/engine/fileOps/tfm.cpp
+++ b/src/engine/fileOps/tfm.cpp
@@ -86,7 +86,7 @@ public:
     // in certain parts of the header and footer)
     // TFM music maker actually uses double 0x80 to escape the 0x80
     // for example: 0xDA 0x80 0x80 0x00 0x23 = 0xDA 0x80 0x00 0x23)
-    if (ret==0x80 && curSeek+1<len) {
+    if (ret==0x80 && curSeek+1<=len) {
       if (buf[curSeek+1]!=0x80) {
         decodeRLE(buf[curSeek-2]);
         tagLenLeft--;
@@ -356,6 +356,10 @@ bool DivEngine::loadTFM(unsigned char* file, size_t len) {
 
         // put a "jump to next pattern" effect if the pattern is smaller than the maximum pattern lengths
         if (patLens[i]!=0 && patLens[i]<ds.subsong[0]->patLen) {
+          if (pat->data[patLens[i]-1][4]==-1 && pat->data[patLens[i]-1][5]==-1) {
+            pat->data[patLens[i]-1][4]=0x0D;
+            pat->data[patLens[i]-1][5]=0x00;
+          }
           pat->data[patLens[i]][4]=0x0D;
           pat->data[patLens[i]][5]=0x00;
         }
@@ -374,14 +378,48 @@ bool DivEngine::loadTFM(unsigned char* file, size_t len) {
         logD("parsing instruments of pattern %d channel %d",i,j);
         for (int k=0; k<256; k++) {
           if (patDataBuf[k]==0) continue;
-          else {
-            pat->data[k][2]=insNumMaps[patDataBuf[k]-1];
-          }
+          pat->data[k][2]=insNumMaps[patDataBuf[k]-1];
         }
 
-        logD("ignoring unused data of pattern %d channel %d",i,j);
-        reader.read(patDataBuf,256);
-        reader.read(patDataBuf,256);
+        // effects
+
+        unsigned char effectNum[256];
+        unsigned char effectVal[256];
+        reader.read(effectNum,256);
+        reader.read(effectVal,256);
+
+        for (int k=0; k<256; k++) {
+          switch (effectNum[k]) {
+          case 0:
+            // arpeggio or no effect (if effect val is 0)
+            if (effectVal[k]==0) break;
+            pat->data[k][4]=effectNum[k];
+            pat->data[k][5]=effectVal[k];
+            break;
+          case 1:
+            // pitch slide up
+          case 2:
+            // pitch slide down
+          case 3:
+            // portamento
+          case 4:
+            // vibrato
+            pat->data[k][4]=effectNum[k];
+            pat->data[k][5]=effectVal[k];
+            break;
+          case 5:
+            // poramento + volume slide
+            pat->data[k][4]=0x06;
+            pat->data[k][5]=effectVal[k];
+            break;
+          case 6:
+            // vibrato + volume slide
+            pat->data[k][4]=0x05;
+            pat->data[k][5]=effectVal[k];
+          default:
+            break;
+          }
+        }
 
         reader.skip(1536);
       }