Ability to use PSG channels without defined instrument in track

src/reskit/soundtrack/engines/echo/dmf.rs

@@ -2,7 +2,7 @@ use std::{collections::HashMap, cmp::{max, min}, error::Error};
 use convert_case::{Case, Casing};
 use samplerate::convert;
 use uuid::Uuid;
-use crate::reskit::{soundtrack::{formats::dmf::{DmfModule, ECHO_EWF_SAMPLE_RATE}, types::{InstrumentType, SampleFormat, Channel, PatternRow}}, utility::{print_warning, Ring}};
+use crate::reskit::{soundtrack::{formats::dmf::{DmfModule, ECHO_EWF_SAMPLE_RATE}, types::{InstrumentType, SampleFormat, Channel, PatternRow}}, utility::{print_warning, Ring, print_info}};
 use super::engine::{EchoFormat, ESF_FM_1, ESF_FM_2, ESF_FM_3, ESF_FM_4, ESF_FM_5, ESF_FM_6, ESF_PSG_1, ESF_PSG_2, ESF_PSG_3, ESF_PSG_4, EchoEvent, get_events_for_row, compact_delays};
 
 
@@ -88,6 +88,16 @@ impl EchoFormat for DmfModule {
                     let mut volume_envelope: Vec<u8> = settings.volume.envelope.iter().map( | long | *long as u8 ).collect();
                     let mut arpeggio_envelope: Vec<i8> = settings.arpeggio.envelope.iter().map( | long | *long as i8 ).collect();
 
+                    // Validations (this makes my life easier when dmf format changes again)
+                    if volume_envelope.is_empty() {
+                        // Push one max volume if there is no volume defined in this instrument
+                        volume_envelope.push( 0x0F );
+                    }
+                    if arpeggio_envelope.is_empty() {
+                        // Push one byte of no arpeggio shift if no arpeggio is defined in this instrument
+                        arpeggio_envelope.push( 0x00 );
+                    }
+
                     // now take a slice of the repeatable portion of the smaller array,
                     // and use it to expand the smaller array to the same size as the
                     // larger array. if there is no repeatable portion, take a one-element

src/reskit/soundtrack/formats/dmf.rs

@@ -1,7 +1,7 @@
 use std::{error::Error, fs::File, io::Read, convert::TryInto, collections::HashMap};
 use flate2::read::ZlibDecoder;
 use linked_hash_set::LinkedHashSet;
-use crate::reskit::{utility::{get_string, get_u8, skip, get_u32, get_i8, get_i32, get_u16, get_i16, print_info}, soundtrack::types::{SampleFormat, PsgEnvelope, Note, Sample, PsgSettings, PatternRow, Effect, DcsgChannelMode, NoiseType, Instrument, InstrumentType, Fm2612Operator, Fm2612Settings}};
+use crate::reskit::{utility::{get_string, get_u8, skip, get_u32, get_i8, get_i32, get_u16, get_i16, print_info}, soundtrack::types::{SampleFormat, PsgEnvelope, Note, Sample, PsgSettings, PatternRow, Effect, DcsgChannelMode, NoiseType, Instrument, InstrumentType, Fm2612Operator, Fm2612Settings, Channel}};
 
 const DMF_MAGIC_NUMBER: &'static str = ".DelekDefleMask.";
 const DMF_SUPPORTED_VERSION: u8 = 27;
@@ -432,7 +432,7 @@ impl DmfModule {
                 _ => return Err( format!( "invalid file: invalid instrument mode {}", mode ) )?
             };
 
-            instruments.push( Instrument { index: i as usize, name, instrument_type } );
+            instruments.push( Instrument { name, instrument_type } );
         }
 
         // Version 27 of DMF specifies "1 wavetable of 0 bytes" for sega megadrive
@@ -581,6 +581,40 @@ impl DmfModule {
             channel_patterns.push( channel_rows );
         }
 
+        // If at least one PSG channel never defines an instrument, insert the default PSG instrument
+        // which is a repeat of zero attentuation.
+        print_info( "Default PSG instruments:" );
+        if DmfModule::uses_default_psg( &channel_patterns )? {
+            print_info( "One or more channels use the default PSG instrument" );
+            instruments.push( Instrument{
+                name: format!( "Default PSG Instrument" ),
+                instrument_type: InstrumentType::PsgDcsg( PsgSettings {
+                    volume: PsgEnvelope {
+                        envelope: vec![ 0x0F as u32 ],
+                        loop_at: Some( 0 ),
+                        settings: HashMap::new()
+                    },
+                    arpeggio: PsgEnvelope {
+                        envelope: vec![],
+                        loop_at: None,
+                        settings: HashMap::new()
+                    },
+                    noise: PsgEnvelope {
+                        envelope: vec![],
+                        loop_at: None,
+                        settings: HashMap::new()
+                    },
+                    wavetable: PsgEnvelope {
+                        envelope: vec![],
+                        loop_at: None,
+                        settings: HashMap::new()
+                    }
+                } )
+            } )
+        } else {
+            print_info( "All PSG channels set instruments" );
+        }
+
         print_info( "PCM Samples:" );
         let mut samples: Vec<Sample> = Vec::new();
         let num_samples = get_u8( bytes.by_ref() )?;
@@ -629,4 +663,32 @@ impl DmfModule {
          )
     }
 
+    pub fn uses_default_psg( channel_patterns: &Vec<Vec<PatternRow>> ) -> Result<bool, Box<dyn Error>> {
+        let mut channels: [Channel; 3] = [
+            Channel::new( 1 ),
+            Channel::new( 2 ),
+            Channel::new( 3 )
+        ];
+
+        for channel_id in 6..9 {
+            let channel_patterns = &channel_patterns[ channel_id ];
+            for row in channel_patterns {
+                // If a set instrument is encountered, just set the instrument on the channel
+                // We will check all three channels to see if at least one does not contain
+                // an active instrument.
+                if row.instrument_index.is_some() {
+                    channels[ channel_id - 6 ].active_instrument = Some( 0 );
+                }
+            }
+        }
+
+        for channel in channels {
+            if channel.active_instrument.is_none() {
+                return Ok( true )
+            }
+        }
+
+        Ok( false )
+    }
+
 }

src/reskit/soundtrack/types.rs

@@ -50,7 +50,6 @@ pub enum InstrumentType {
 
 #[derive(Debug)]
 pub struct Instrument {
-    pub index: usize,
     pub name: String,
     pub instrument_type: InstrumentType
 }