Fix bugs in modulator handling

src/sfloader/fluid_defsfont.c

@@ -1616,18 +1616,6 @@ fluid_zone_mod_import_sfont(char *zone_name, fluid_mod_t **mod, SFZone *sfzone)
             /* This shouldn't happen - unknown type!
              * Deactivate the modulator by setting the amount to 0. */
             mod_dest->amount = 0;
-        }  
-
-        /* Note: When primary source input (src1) is set to General Controller 'No Controller',
-           output will be forced to 0.0 at synthesis time (see fluid_mod_get_value()).
-           That means that the minimum value of the modulator will be always 0.0.
-           We need to force amount value to 0 to ensure a correct evaluation of the minimum
-           value later (see fluid_voice_get_lower_boundary_for_attenuation()).
-        */
-        if(((mod_dest->flags1 & FLUID_MOD_CC) == FLUID_MOD_GC) && 
-            (mod_dest->src1 == FLUID_MOD_NONE))
-        {
-            mod_dest->amount = 0;
         }
 
         /* *** Dest *** */
@@ -1639,17 +1627,6 @@ fluid_zone_mod_import_sfont(char *zone_name, fluid_mod_t **mod, SFZone *sfzone)
             /* This shouldn't happen - unknown type!
              * Deactivate the modulator by setting the amount to 0. */
             mod_dest->amount = 0;
-        }  
-        /* Note: When secondary source input (src2) is set to General Controller 'No Controller',
-           output will be forced to +1.0 at synthesis time (see fluid_mod_get_value()).
-           That means that this source will behave unipolar only. We need to force the
-           unipolar flag to ensure a correct evaluation of the minimum
-           value later (see fluid_voice_get_lower_boundary_for_attenuation()).
-        */
-        if(((mod_dest->flags2 & FLUID_MOD_CC) == FLUID_MOD_GC) && 
-            (mod_dest->src2 == FLUID_MOD_NONE))
-        {
-            mod_dest->flags2 &= ~FLUID_MOD_BIPOLAR;
         }
 
         /**

src/synth/fluid_mod.c

@@ -219,7 +219,7 @@ fluid_mod_get_source_value(const unsigned char mod_src,
 
         if(mod_src == PORTAMENTO_CTRL)
         {
-            // an invalid portamento fromkey should be treated as 0 when it's actually used for moulating
+            // an invalid portamento fromkey should be treated as 0 when it's actually used for modulating
             if(!fluid_channel_is_valid_note(val))
             {
                 val = 0;
@@ -396,23 +396,17 @@ fluid_mod_transform_source_value(fluid_real_t val, unsigned char mod_flags, cons
  *
  * Output = Transform(Amount * Map(primary source input) * Map(secondary source input))
  *
- * Notes:
- * 1)fluid_mod_get_value, ignores the Transform operator. The result is:
+ * Note:
+ * fluid_mod_get_value ignores the Transform operator. The result is:
  *
  *   Output = Amount * Map(primary source input) * Map(secondary source input)
- *
- * 2)When primary source input (src1) is set to General Controller 'No Controller',
- *   output is forced to 0.
- *
- * 3)When secondary source input (src2) is set to General Controller 'No Controller',
- *   output is forced to +1.0 
  */
 fluid_real_t
 fluid_mod_get_value(fluid_mod_t *mod, fluid_voice_t *voice)
 {
     extern fluid_mod_t default_vel2filter_mod;
 
-    fluid_real_t v1 = 0.0, v2 = 1.0;
+    fluid_real_t v1, v2;
     fluid_real_t final_value;
     /* The wording of the default modulators refers to a range of 127/128.
      * And the table in section 9.5.3 suggests, that this mapping should be applied
@@ -451,56 +445,32 @@ fluid_mod_get_value(fluid_mod_t *mod, fluid_voice_t *voice)
      * */
     if(fluid_mod_test_identity(mod, &default_vel2filter_mod))
     {
-// S. Christian Collins' mod, to stop forcing velocity based filtering
         /*
             if (voice->vel < 64){
               return (fluid_real_t) mod->amount / 2.0;
             } else {
               return (fluid_real_t) mod->amount * (127 - voice->vel) / 127;
             }
+            return (fluid_real_t) mod->amount / 2.0;
         */
-        return 0; // (fluid_real_t) mod->amount / 2.0;
+        // S. Christian Collins' mod, to stop forcing velocity based filtering
+        return 0;
     }
 
-// end S. Christian Collins' mod
-
-    /* get the initial value of the first source */
-    if(mod->src1 > 0)
-    {
-        v1 = fluid_mod_get_source_value(mod->src1, mod->flags1, &range1, voice);
-
-        /* transform the input value */
-        v1 = fluid_mod_transform_source_value(v1, mod->flags1, range1);
-    }
-    /* When primary source input (src1) is set to General Controller 'No Controller',
-       output is forced to 0.0
-    */
-    else
-    {
-        return 0.0;
-    }
+    /* Get the initial value of the first source.
+     *
+     * Even if the src is FLUID_MOD_NONE, the value has to be transformed, see #1389
+     */
+    v1 = fluid_mod_get_source_value(mod->src1, mod->flags1, &range1, voice);
 
-    /* no need to go further */
-    if(v1 == 0.0f)
-    {
-        return 0.0f;
-    }
+    /* transform the input value */
+    v1 = fluid_mod_transform_source_value(v1, mod->flags1, range1);
 
     /* get the second input source */
-    if(mod->src2 > 0)
-    {
-        v2 = fluid_mod_get_source_value(mod->src2, mod->flags2, &range2, voice);
+    v2 = fluid_mod_get_source_value(mod->src2, mod->flags2, &range2, voice);
 
-        /* transform the second input value */
-        v2 = fluid_mod_transform_source_value(v2, mod->flags2, range2);
-    }
-    /* When secondary source input (src2) is set to General Controller 'No Controller',
-       output is forced to +1.0
-    */
-    else
-    {
-        v2 = 1.0f;
-    }
+    /* transform the second input value */
+    v2 = fluid_mod_transform_source_value(v2, mod->flags2, range2);
 
     /* it indeed is as simple as that: */
     final_value = (fluid_real_t) mod->amount * v1 * v2;

src/synth/fluid_voice.c

@@ -1791,7 +1791,7 @@ fluid_voice_get_lower_boundary_for_attenuation(fluid_voice_t *voice)
                3)absolute value of amount.
 
                When at least one source mapping is bipolar:
-			     min_val is -|amount| regardless the sign of amount.
+                 min_val is -|amount| regardless the sign of amount.
                When both sources mapping are unipolar:
                  min_val is -|amount|, if amount is negative.
                  min_val is 0, if amount is positive