Envelope fixes [2/2]:

Updated the envelopes, so there are two separate handlers. One for
XM/IMF and one for IT.

Almost totally rewrote the envelope handling, so it behaves like
FastTracker II does, specially when used together with XM effect L.

These two fixes make Ebony Owl Netsuke.xm to play correctly.

Author: neumatho

libmikmod/include/mikmod_internals.h

@@ -424,6 +424,7 @@ typedef struct FILTER {
 #define EF_SUSTAIN      2
 #define EF_LOOP         4
 #define EF_VOLENV       8
+#define EF_ITMODE       16
 
 /* New Note Action Flags */
 #define NNA_CUT         0
@@ -461,17 +462,17 @@ typedef struct FILTER {
 #define LAST_PATTERN    (UWORD)(-1) /* special ``end of song'' pattern */
 
 typedef struct ENVPR {
-    UBYTE  flg;     /* envelope flag */
-    UBYTE  pts;     /* number of envelope points */
-    UBYTE  susbeg;  /* envelope sustain index begin */
-    UBYTE  susend;  /* envelope sustain index end */
-    BOOL   susactive;/* Indicate if sustain is active (no interpolation) */
-    UBYTE  beg;     /* envelope loop begin */
-    UBYTE  end;     /* envelope loop end */
-    SWORD  p;       /* current envelope counter */
-    UWORD  index;   /* envelope index for the point after the current one */
-    SWORD  lastvalue;/* the last calculated value */
-    ENVPT* env;     /* envelope points */
+    UBYTE  flg;         /* envelope flag */
+    UBYTE  pts;         /* number of envelope points */
+    UBYTE  susbeg;      /* envelope sustain index begin */
+    UBYTE  susend;      /* envelope sustain index end */
+    UBYTE  loopbeg;     /* envelope loop begin */
+    UBYTE  loopend;     /* envelope loop end */
+    SWORD  tick;        /* current envelope counter */
+    UWORD  index;       /* envelope index for the point after the current one */
+    BOOL   interpolate; /* Indicate if interpolation should be done */
+    SWORD  lastvalue;   /* the last calculated value */
+    ENVPT* env;         /* envelope points */
 } ENVPR;
 
 typedef struct MP_CHANNEL {

libmikmod/loaders/load_it.c

@@ -827,7 +827,9 @@ static BOOL IT_Load(BOOL curious)
 				return 0;
 			}
 
-			d->volflg|=EF_VOLENV;
+			d->volflg|=(EF_VOLENV | EF_ITMODE);
+			d->panflg|=EF_ITMODE;
+			d->pitflg|=EF_ITMODE;
 			d->insname = DupStr(ih.name,26,0);
 			d->nnatype = ih.nna & NNA_MASK;