Implement pitch bend.

Subversion-branch: /branches/opl-branch
Subversion-revision: 1658

1 files changed, 213 insertions, 49 deletions

diff --git a/src/i_oplmusic.c b/src/i_oplmusic.c
index 1ac502f5..e9fdb395 100644
--- a/src/i_oplmusic.c
+++ b/src/i_oplmusic.c
@@ -91,6 +91,11 @@ typedef struct
     // Volume level
 
     int volume;
+
+    // Pitch bend value:
+
+    int bend;
+
 } opl_channel_data_t;
 
 // Data associated with a track that is currently playing.
@@ -127,7 +132,12 @@ struct opl_voice_s
     // The channel currently using this voice.
     opl_channel_data_t *channel;
 
-    // The note that this voice is playing.
+    // The midi key that this voice is playing.
+    unsigned int key;
+
+    // The note being played.  This is normally the same as
+    // the key, but if the instrument is a fixed pitch
+    // instrument, it is different.
     unsigned int note;
 
     // The frequency value being used.
@@ -153,18 +163,120 @@ static const int voice_operators[2][OPL_NUM_VOICES] = {
 
 // Frequency values to use for each note.
 
-static const unsigned int note_frequencies[] = {
-
-    // These frequencies are only used for the first seven
-    // MIDI note values:
-
-    0x158, 0x16d, 0x183, 0x19a, 0x1b2, 0x1cc, 0x1e7, 
-
-    // These frequencies are used repeatedly, cycling around
-    // for each octave:
-
-    0x204, 0x223, 0x244, 0x266, 0x28b, 0x2b1,
-    0x2da, 0x306, 0x334, 0x365, 0x398, 0x3cf,
+static const unsigned short frequency_curve[] = {
+
+    0x133, 0x133, 0x134, 0x134, 0x135, 0x136, 0x136, 0x137,   // -1
+    0x137, 0x138, 0x138, 0x139, 0x139, 0x13a, 0x13b, 0x13b,
+    0x13c, 0x13c, 0x13d, 0x13d, 0x13e, 0x13f, 0x13f, 0x140,
+    0x140, 0x141, 0x142, 0x142, 0x143, 0x143, 0x144, 0x144,
+
+    0x145, 0x146, 0x146, 0x147, 0x147, 0x148, 0x149, 0x149,   // -2
+    0x14a, 0x14a, 0x14b, 0x14c, 0x14c, 0x14d, 0x14d, 0x14e,
+    0x14f, 0x14f, 0x150, 0x150, 0x151, 0x152, 0x152, 0x153,
+    0x153, 0x154, 0x155, 0x155, 0x156, 0x157, 0x157, 0x158,
+
+    // These are used for the first seven MIDI note values:
+
+    0x158, 0x159, 0x15a, 0x15a, 0x15b, 0x15b, 0x15c, 0x15d,   // 0
+    0x15d, 0x15e, 0x15f, 0x15f, 0x160, 0x161, 0x161, 0x162,
+    0x162, 0x163, 0x164, 0x164, 0x165, 0x166, 0x166, 0x167,
+    0x168, 0x168, 0x169, 0x16a, 0x16a, 0x16b, 0x16c, 0x16c,
+
+    0x16d, 0x16e, 0x16e, 0x16f, 0x170, 0x170, 0x171, 0x172,   // 1
+    0x172, 0x173, 0x174, 0x174, 0x175, 0x176, 0x176, 0x177,
+    0x178, 0x178, 0x179, 0x17a, 0x17a, 0x17b, 0x17c, 0x17c,
+    0x17d, 0x17e, 0x17e, 0x17f, 0x180, 0x181, 0x181, 0x182,
+
+    0x183, 0x183, 0x184, 0x185, 0x185, 0x186, 0x187, 0x188,   // 2
+    0x188, 0x189, 0x18a, 0x18a, 0x18b, 0x18c, 0x18d, 0x18d,
+    0x18e, 0x18f, 0x18f, 0x190, 0x191, 0x192, 0x192, 0x193,
+    0x194, 0x194, 0x195, 0x196, 0x197, 0x197, 0x198, 0x199,
+
+    0x19a, 0x19a, 0x19b, 0x19c, 0x19d, 0x19d, 0x19e, 0x19f,   // 3
+    0x1a0, 0x1a0, 0x1a1, 0x1a2, 0x1a3, 0x1a3, 0x1a4, 0x1a5,
+    0x1a6, 0x1a6, 0x1a7, 0x1a8, 0x1a9, 0x1a9, 0x1aa, 0x1ab,
+    0x1ac, 0x1ad, 0x1ad, 0x1ae, 0x1af, 0x1b0, 0x1b0, 0x1b1,
+
+    0x1b2, 0x1b3, 0x1b4, 0x1b4, 0x1b5, 0x1b6, 0x1b7, 0x1b8,   // 4
+    0x1b8, 0x1b9, 0x1ba, 0x1bb, 0x1bc, 0x1bc, 0x1bd, 0x1be,
+    0x1bf, 0x1c0, 0x1c0, 0x1c1, 0x1c2, 0x1c3, 0x1c4, 0x1c4,
+    0x1c5, 0x1c6, 0x1c7, 0x1c8, 0x1c9, 0x1c9, 0x1ca, 0x1cb,
+
+    0x1cc, 0x1cd, 0x1ce, 0x1ce, 0x1cf, 0x1d0, 0x1d1, 0x1d2,   // 5
+    0x1d3, 0x1d3, 0x1d4, 0x1d5, 0x1d6, 0x1d7, 0x1d8, 0x1d8,
+    0x1d9, 0x1da, 0x1db, 0x1dc, 0x1dd, 0x1de, 0x1de, 0x1df,
+    0x1e0, 0x1e1, 0x1e2, 0x1e3, 0x1e4, 0x1e5, 0x1e5, 0x1e6,
+
+    0x1e7, 0x1e8, 0x1e9, 0x1ea, 0x1eb, 0x1ec, 0x1ed, 0x1ed,   // 6
+    0x1ee, 0x1ef, 0x1f0, 0x1f1, 0x1f2, 0x1f3, 0x1f4, 0x1f5,
+    0x1f6, 0x1f6, 0x1f7, 0x1f8, 0x1f9, 0x1fa, 0x1fb, 0x1fc,
+    0x1fd, 0x1fe, 0x1ff, 0x200, 0x201, 0x201, 0x202, 0x203,
+
+    // First note of looped range used for all octaves:
+
+    0x204, 0x205, 0x206, 0x207, 0x208, 0x209, 0x20a, 0x20b,   // 7
+    0x20c, 0x20d, 0x20e, 0x20f, 0x210, 0x210, 0x211, 0x212,
+    0x213, 0x214, 0x215, 0x216, 0x217, 0x218, 0x219, 0x21a,
+    0x21b, 0x21c, 0x21d, 0x21e, 0x21f, 0x220, 0x221, 0x222,
+
+    0x223, 0x224, 0x225, 0x226, 0x227, 0x228, 0x229, 0x22a,   // 8
+    0x22b, 0x22c, 0x22d, 0x22e, 0x22f, 0x230, 0x231, 0x232,
+    0x233, 0x234, 0x235, 0x236, 0x237, 0x238, 0x239, 0x23a,
+    0x23b, 0x23c, 0x23d, 0x23e, 0x23f, 0x240, 0x241, 0x242,
+
+    0x244, 0x245, 0x246, 0x247, 0x248, 0x249, 0x24a, 0x24b,   // 9
+    0x24c, 0x24d, 0x24e, 0x24f, 0x250, 0x251, 0x252, 0x253,
+    0x254, 0x256, 0x257, 0x258, 0x259, 0x25a, 0x25b, 0x25c,
+    0x25d, 0x25e, 0x25f, 0x260, 0x262, 0x263, 0x264, 0x265,
+
+    0x266, 0x267, 0x268, 0x269, 0x26a, 0x26c, 0x26d, 0x26e,   // 10
+    0x26f, 0x270, 0x271, 0x272, 0x273, 0x275, 0x276, 0x277,
+    0x278, 0x279, 0x27a, 0x27b, 0x27d, 0x27e, 0x27f, 0x280,
+    0x281, 0x282, 0x284, 0x285, 0x286, 0x287, 0x288, 0x289,
+
+    0x28b, 0x28c, 0x28d, 0x28e, 0x28f, 0x290, 0x292, 0x293,   // 11
+    0x294, 0x295, 0x296, 0x298, 0x299, 0x29a, 0x29b, 0x29c,
+    0x29e, 0x29f, 0x2a0, 0x2a1, 0x2a2, 0x2a4, 0x2a5, 0x2a6,
+    0x2a7, 0x2a9, 0x2aa, 0x2ab, 0x2ac, 0x2ae, 0x2af, 0x2b0,
+
+    0x2b1, 0x2b2, 0x2b4, 0x2b5, 0x2b6, 0x2b7, 0x2b9, 0x2ba,   // 12
+    0x2bb, 0x2bd, 0x2be, 0x2bf, 0x2c0, 0x2c2, 0x2c3, 0x2c4,
+    0x2c5, 0x2c7, 0x2c8, 0x2c9, 0x2cb, 0x2cc, 0x2cd, 0x2ce,
+    0x2d0, 0x2d1, 0x2d2, 0x2d4, 0x2d5, 0x2d6, 0x2d8, 0x2d9,
+
+    0x2da, 0x2dc, 0x2dd, 0x2de, 0x2e0, 0x2e1, 0x2e2, 0x2e4,   // 13
+    0x2e5, 0x2e6, 0x2e8, 0x2e9, 0x2ea, 0x2ec, 0x2ed, 0x2ee,
+    0x2f0, 0x2f1, 0x2f2, 0x2f4, 0x2f5, 0x2f6, 0x2f8, 0x2f9,
+    0x2fb, 0x2fc, 0x2fd, 0x2ff, 0x300, 0x302, 0x303, 0x304,
+
+    0x306, 0x307, 0x309, 0x30a, 0x30b, 0x30d, 0x30e, 0x310,   // 14
+    0x311, 0x312, 0x314, 0x315, 0x317, 0x318, 0x31a, 0x31b,
+    0x31c, 0x31e, 0x31f, 0x321, 0x322, 0x324, 0x325, 0x327,
+    0x328, 0x329, 0x32b, 0x32c, 0x32e, 0x32f, 0x331, 0x332,
+
+    0x334, 0x335, 0x337, 0x338, 0x33a, 0x33b, 0x33d, 0x33e,   // 15
+    0x340, 0x341, 0x343, 0x344, 0x346, 0x347, 0x349, 0x34a,
+    0x34c, 0x34d, 0x34f, 0x350, 0x352, 0x353, 0x355, 0x357,
+    0x358, 0x35a, 0x35b, 0x35d, 0x35e, 0x360, 0x361, 0x363,
+
+    0x365, 0x366, 0x368, 0x369, 0x36b, 0x36c, 0x36e, 0x370,   // 16
+    0x371, 0x373, 0x374, 0x376, 0x378, 0x379, 0x37b, 0x37c,
+    0x37e, 0x380, 0x381, 0x383, 0x384, 0x386, 0x388, 0x389,
+    0x38b, 0x38d, 0x38e, 0x390, 0x392, 0x393, 0x395, 0x397,
+
+    0x398, 0x39a, 0x39c, 0x39d, 0x39f, 0x3a1, 0x3a2, 0x3a4,   // 17
+    0x3a6, 0x3a7, 0x3a9, 0x3ab, 0x3ac, 0x3ae, 0x3b0, 0x3b1,
+    0x3b3, 0x3b5, 0x3b7, 0x3b8, 0x3ba, 0x3bc, 0x3bd, 0x3bf,
+    0x3c1, 0x3c3, 0x3c4, 0x3c6, 0x3c8, 0x3ca, 0x3cb, 0x3cd,
+
+    // The last note has an incomplete range, and loops round back to
+    // the start.  Note that the last value is actually a buffer overrun
+    // and does not fit with the other values.
+
+    0x3cf, 0x3d1, 0x3d2, 0x3d4, 0x3d6, 0x3d8, 0x3da, 0x3db,   // 18
+    0x3dd, 0x3df, 0x3e1, 0x3e3, 0x3e4, 0x3e6, 0x3e8, 0x3ea,
+    0x3ec, 0x3ed, 0x3ef, 0x3f1, 0x3f3, 0x3f5, 0x3f6, 0x3f8,
+    0x3fa, 0x3fc, 0x3fe, 0x36c,
 };
 
 // Mapping from MIDI volume level to OPL level value.
@@ -501,7 +613,7 @@ static void SetOperatorVolume(genmidi_op_t *op, unsigned int volume,
     reg_volume = (op_volume * volume) / 128;
     reg_volume = (0x3f - reg_volume) | op->scale;
 
-    // Update the register, if necessary:
+    // Update the register, if neccessary:
 
     if (*current_volume != reg_volume)
     {
@@ -673,13 +785,13 @@ static void I_OPL_SetMusicVolume(int volume)
     current_music_volume = volume;
 }
 
-static opl_voice_t *FindVoiceForNote(opl_channel_data_t *channel, int note)
+static opl_voice_t *FindVoiceForKey(opl_channel_data_t *channel, int key)
 {
     unsigned int i;
 
     for (i=0; i<OPL_NUM_VOICES; ++i)
     {
-        if (voices[i].channel == channel && voices[i].note == note)
+        if (voices[i].channel == channel && voices[i].key == key)
         {
             return &voices[i];
         }
@@ -693,6 +805,8 @@ static void VoiceNoteOff(opl_voice_t *voice)
     WriteRegister(OPL_REGS_FREQ_2 + voice->index, voice->freq >> 8);
 }
 
+// Get the frequency that we should be using for a voice.
+
 static void NoteOffEvent(opl_track_data_t *track, midi_event_t *event)
 {
     opl_voice_t *voice;
@@ -707,7 +821,7 @@ static void NoteOffEvent(opl_track_data_t *track, midi_event_t *event)
 
     // Find the voice being used to play the note.
 
-    voice = FindVoiceForNote(channel, event->data.channel.param1);
+    voice = FindVoiceForKey(channel, event->data.channel.param1);
 
     if (voice == NULL)
     {
@@ -721,29 +835,47 @@ static void NoteOffEvent(opl_track_data_t *track, midi_event_t *event)
     ReleaseVoice(voice);
 }
 
-// Given a MIDI note number, get the corresponding OPL
-// frequency value to use.
-
-static unsigned int FrequencyForNote(unsigned int note)
+static unsigned int FrequencyForVoice(opl_voice_t *voice)
 {
+    unsigned int freq_index;
     unsigned int octave;
-    unsigned int key_num;
+    unsigned int sub_index;
 
-    // The first seven frequencies in the frequencies array are used
-    // only for the first seven MIDI notes.  After this, the frequency
-    // value loops around the same twelve notes, increasing the
-    // octave.
+    freq_index = 64 + 32 * voice->note + voice->channel->bend;
 
-    if (note < 7)
+    // The first 7 notes use the start of the table, while
+    // consecutive notes loop around the latter part.
+
+    if (freq_index < 284)
     {
-        return note_frequencies[note];
+        return frequency_curve[freq_index];
     }
-    else
+
+    sub_index = (freq_index - 284) % (12 * 32);
+    octave = (freq_index - 284) / (12 * 32);
+
+    // Calculate the resulting register value to use for the frequency.
+
+    return frequency_curve[sub_index + 284] | (octave << 10);
+}
+
+// Update the frequency that a voice is programmed to use.
+
+static void UpdateVoiceFrequency(opl_voice_t *voice)
+{
+    unsigned int freq;
+
+    // Calculate the frequency to use for this voice and update it
+    // if neccessary.
+
+    freq = FrequencyForVoice(voice);
+
+    if (voice->freq != freq)
     {
-        octave = (note - 7) / 12;
-        key_num = (note - 7) % 12;
+        WriteRegister(OPL_REGS_FREQ_1 + voice->index, freq & 0xff);
+        WriteRegister(OPL_REGS_FREQ_2 + voice->index, (freq >> 8) | 0x20);
 
-        return note_frequencies[key_num + 7] | (octave << 10);
+        voice->freq = freq;
     }
 }
 
@@ -752,7 +884,7 @@ static void NoteOnEvent(opl_track_data_t *track, midi_event_t *event)
     genmidi_instr_t *instrument;
     opl_voice_t *voice;
     opl_channel_data_t *channel;
-    unsigned int note;
+    unsigned int key;
     unsigned int volume;
 
     printf("note on: channel %i, %i, %i\n",
@@ -763,19 +895,19 @@ static void NoteOnEvent(opl_track_data_t *track, midi_event_t *event)
     // The channel.
 
     channel = &track->channels[event->data.channel.channel];
-    note = event->data.channel.param1;
+    key = event->data.channel.param1;
     volume = event->data.channel.param2;
 
-    // Percussion channel (10) is treated differently to normal notes.
+    // Percussion channel (10) is treated differently.
 
     if (event->data.channel.channel == 9)
     {
-        if (note < 35 || note > 81)
+        if (key < 35 || key > 81)
         {
             return;
         }
 
-        instrument = &percussion_instrs[note - 35];
+        instrument = &percussion_instrs[key - 35];
     }
     else
     {
@@ -793,7 +925,19 @@ static void NoteOnEvent(opl_track_data_t *track, midi_event_t *event)
     }
 
     voice->channel = channel;
-    voice->note = note;
+    voice->key = key;
+
+    // Work out the note to use.  This is normally the same as
+    // the key, unless it is a fixed pitch instrument.
+
+    if ((instrument->flags & GENMIDI_FLAG_FIXED) != 0)
+    {
+        voice->note = instrument->fixed_note;
+    }
+    else
+    {
+        voice->note = key;
+    }
 
     // Program the voice with the instrument data:
 
@@ -803,19 +947,10 @@ static void NoteOnEvent(opl_track_data_t *track, midi_event_t *event)
 
     SetVoiceVolume(voice, volume);
 
-    // Fixed pitch?
-
-    if ((instrument->flags & GENMIDI_FLAG_FIXED) != 0)
-    {
-        note = instrument->fixed_note;
-    }
-
     // Write the frequency value to turn the note on.
 
-    voice->freq = FrequencyForNote(note);
-
-    WriteRegister(OPL_REGS_FREQ_1 + voice->index, voice->freq & 0xff);
-    WriteRegister(OPL_REGS_FREQ_2 + voice->index, (voice->freq >> 8) | 0x20);
+    voice->freq = 0;
+    UpdateVoiceFrequency(voice);
 }
 
 static void ProgramChangeEvent(opl_track_data_t *track, midi_event_t *event)
@@ -877,6 +1012,30 @@ static void ControllerEvent(opl_track_data_t *track, midi_event_t *event)
     }
 }
 
+// Process a pitch bend event.
+
+static void PitchBendEvent(opl_track_data_t *track, midi_event_t *event)
+{
+    opl_channel_data_t *channel;
+    unsigned int i;
+
+    // Update the channel bend value.  Only the MSB of the pitch bend
+    // value is considered: this is what Doom does.
+
+    channel = &track->channels[event->data.channel.channel];
+    channel->bend = event->data.channel.param2 - 64;
+
+    // Update all voices for this channel.
+
+    for (i=0; i<OPL_NUM_VOICES; ++i)
+    {
+        if (voices[i].channel == channel)
+        {
+            UpdateVoiceFrequency(&voices[i]);
+        }
+    }
+}
+
 // Process a meta event.
 
 static void MetaEvent(opl_track_data_t *track, midi_event_t *event)
@@ -931,6 +1090,10 @@ static void ProcessEvent(opl_track_data_t *track, midi_event_t *event)
             ProgramChangeEvent(track, event);
             break;
 
+        case MIDI_EVENT_PITCH_BEND:
+            PitchBendEvent(track, event);
+            break;
+
         case MIDI_EVENT_META:
             MetaEvent(track, event);
             break;
@@ -1029,6 +1192,7 @@ static void InitChannel(opl_track_data_t *track, opl_channel_data_t *channel)
 
     channel->instrument = &main_instrs[0];
     channel->volume = 127;
+    channel->bend = 0;
 }
 
 // Start a MIDI track playing: