diff --git a/default_bus_layout.tres b/default_bus_layout.tres index 80e615e..78b14ac 100644 --- a/default_bus_layout.tres +++ b/default_bus_layout.tres @@ -16,7 +16,7 @@ bus/1/name = "BGM" bus/1/solo = false bus/1/mute = false bus/1/bypass_fx = false -bus/1/volume_db = 0.0 +bus/1/volume_db = -6.0 bus/1/send = "Master" bus/2/name = "BGM0" bus/2/solo = false diff --git a/shaders/audio_renderer.gdshader b/shaders/audio_renderer.gdshader index 5007b9e..01561f3 100644 --- a/shaders/audio_renderer.gdshader +++ b/shaders/audio_renderer.gdshader @@ -125,11 +125,98 @@ float get_instrument_sample(float instrument_index, float pitch_scale, float t, return rescale_int16(unpack_int16(get_inst_texel(sample_xy))); } +const int NUM_CHANNELS = 8; +const int MAX_CHANNEL_NOTE_EVENTS = 2048; +const int NUM_CHANNEL_NOTE_PROBES = 11; // log2(MAX_CHANNEL_NOTE_EVENTS) +uniform sampler2D midi_events; +uniform vec2 midi_events_size = vec2(2048.0, 16.0); +// SDR rendering only gives us [0.0, 1.0] from the sampler2D so we need to rescale it. +uniform float t_scale = 524.0; // Change this if we need longer than 8min44sec. +// ^ Other things will also need changing, since 4096x4096 = 8MSamples is barely over 524 seconds at 32kHz. +vec4 get_midi_texel(float x, float y) { + return texture(midi_events, vec2(x, y)/midi_events_size).xyzw; +} +vec2 unpack_float(float f) { + // Unpack two 10bit values from a single channel (23bit mantissa) + float a = f * 1024.0; + float x = trunc(a) / 1023.0; + float y = fract(a) * 1024.0 / 1023.0; + return vec2(x, y); +} +vec4 render_song(float sample_progress) { + // Each texel rendered is a stereo S16LE frame representing 1/32000 of a second + // BGM sequences should be relatively small so it should be fine to use RGBAF (4x f32s per texel) as our data texture + // 2048 is an established safe texture dimension so may as well go 2048 wide + float t = sample_progress/output_mixrate; + vec2 downmixed_stereo = vec2(0.0); + + // Binary search the channels + for (int channel = 0; channel < NUM_CHANNELS; channel++) { + float row = float(channel * 2); + float event_idx = 0.0; + for (int i = 0; i < NUM_CHANNEL_NOTE_PROBES; i++) { + float step_size = exp2(float(NUM_CHANNEL_NOTE_PROBES - i - 1)); + vec4 note_event = get_midi_texel(event_idx + step_size, row); + float t_start = note_event.x; + event_idx += (t >= t_start) ? step_size : 0.0; + } + vec4 note_event = get_midi_texel(event_idx, row); + vec4 note_event_supplement = get_midi_texel(event_idx, row+1.0); + float t_start = note_event.x * t_scale; + float t_end = note_event.y * t_scale; + vec2 instrument_and_pitch = unpack_float(note_event.z); + float instrument_idx = instrument_and_pitch.x * 1023.0; + float pitch_idx = instrument_and_pitch.y * 1023.0; // TODO: Maybe rescale this for fine tuning? Don't use it raw because 2^(127-71) is MASSIVE, keep the power-of-2 calcs in shader. + vec2 velocity_and_pan = unpack_float(note_event_supplement.w); // Can leave these as [0.0, 1.0] and then mix appropriately + float velocity = velocity_and_pan.x; + float pan = velocity_and_pan.y; + vec2 attack_and_decay = unpack_float(note_event_supplement.x); + vec2 sustain_and_release = unpack_float(note_event_supplement.y); + // TBD = note_event_supplement.zw; - tremolo/vibrato/noise/pan_lfo/pitchbend/echo remain + + // For now, just branch this + if (t_end > t) { + float samp = get_instrument_sample(instrument_idx, get_pitch_scale(pitch_idx), t-t_start, t_end-t_start); + samp *= velocity; + // TODO: do some ADSR here? + downmixed_stereo += samp * vec2(1.0-pan, pan); // TODO: double it to maintain the mono level on each channel at center=0.5? + } + } + // Convert the stereo float audio to S16LE + return vec4(pack_float_to_int16(downmixed_stereo.x), pack_float_to_int16(downmixed_stereo.y)); +} void fragment() { // GLES2 vec2 uv = vec2(UV.x, 1.0-UV.y); uv = (trunc(uv*UV_QUANTIZE)+0.5)/UV_QUANTIZE; - - COLOR.xyzw = test_writeback(uv); + // COLOR.xyzw = test_writeback(uv); + COLOR.xyzw = render_song(dot(uv, vec2(1.0, midi_events_size.x))); } + +// const int MAX_TEMPO_EVENTS = 256; +// const int NUM_TEMPO_PROBES = 8; // log2(MAX_TEMPO_EVENTS) + // Because tempo is dynamic, it will need to be encoded into a header in song_texture + // // Binary search the first row for tempo information + // float tempo_idx = 0.0; + // vec4 tempo_event; + // float t_start; + // for (int i = 0; i < NUM_TEMPO_PROBES; i++) { + // float step_size = exp2(float(NUM_TEMPO_PROBES - i - 1)); + // tempo_event = get_midi_texel(tempo_idx + step_size, 0.0); + // t_start = tempo_event.x; + // tempo_idx += (t >= t_start) ? step_size : 0.0; + // } + // float beat_start = tempo_event.y; + // float tempo_start = tempo_event.z; + // float tempo_end = tempo_event.w; // For tempo slides + // vec4 next_tempo_event = get_midi_texel(tempo_idx + 1.0, 0.0); + // float t_end = next_tempo_event.x; + // float beat_end = next_tempo_event.y; + // // Use the tempo information to convert wall time to beat time + // float t0 = t - t_start; + // float t_length = t_end - t_start; + // float tempo_section_progression = t0 / t_length; + // float tempo_at_t = mix(tempo_start, tempo_end, tempo_section_progression); + // float current_beat = beat_start + (t0 * (tempo_start+tempo_at_t) * 0.5); // Use the average tempo across the period to turn integration into area of a rectangle + // Now that we have our position on the beatmap,