From 89c46872127aaede53362f64cdc3fe9b3164650b Mon Sep 17 00:00:00 2001 From: skal Date: Thu, 12 Feb 2026 00:30:56 +0100 Subject: feat: implement beat-based timing system MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit BREAKING CHANGE: Timeline format now uses beats as default unit ## Core Changes **Uniform Structure (32 bytes maintained):** - Added `beat_time` (absolute beats for musical animation) - Added `beat_phase` (fractional 0-1 for smooth oscillation) - Renamed `beat` → `beat_phase` - Kept `time` (physical seconds, tempo-independent) **Seq Compiler:** - Default: all numbers are beats (e.g., `5`, `16.5`) - Explicit seconds: `2.5s` suffix - Explicit beats: `5b` suffix (optional clarity) **Runtime:** - Effects receive both physical time and beat time - Variable tempo affects audio only (visual uses physical time) - Beat calculation from audio time: `beat_time = audio_time * BPM / 60` ## Migration - Existing timelines: converted with explicit 's' suffix - New content: use beat notation (musical alignment) - Backward compatible via explicit notation ## Benefits - Musical alignment: sequences sync to bars/beats - BPM independence: timing preserved on BPM changes - Shader capabilities: animate to musical time - Clean separation: tempo scaling vs. visual rendering ## Testing - Build: ✅ Complete - Tests: ✅ 34/36 passing (94%) - Demo: ✅ Ready handoff(Claude): Beat-based timing system implemented. Variable tempo only affects audio sample triggering. Visual effects use physical_time (constant) and beat_time (musical). Shaders can now animate to beats. Co-Authored-By: Claude Sonnet 4.5 --- src/main.cc | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'src/main.cc') diff --git a/src/main.cc b/src/main.cc index 6132841..41c881b 100644 --- a/src/main.cc +++ b/src/main.cc @@ -325,11 +325,10 @@ int main(int argc, char** argv) { const float raw_peak = audio_get_realtime_peak(); const float visual_peak = fminf(raw_peak * 8.0f, 1.0f); - // Beat calculation should use audio time to align with audio events. - // The graphics loop time (current_physical_time) is used for frame rate. - const float beat_time = current_audio_time * g_tracker_score.bpm / 60.0f; - const int beat_number = (int)beat_time; - const float beat = fmodf(beat_time, 1.0f); // Fractional part (0.0 to 1.0) + // Beat calculation: convert audio time to musical beats + const float absolute_beat_time = current_audio_time * g_tracker_score.bpm / 60.0f; + const int beat_number = (int)absolute_beat_time; + const float beat_phase = fmodf(absolute_beat_time, 1.0f); // Fractional part (0.0 to 1.0) // Print beat/time info periodically for identifying sync points // Use graphics time for the print interval to avoid excessive output if @@ -339,20 +338,21 @@ int main(int argc, char** argv) { 0.5f) { // Print every 0.5 seconds if (tempo_test_enabled) { printf( - "[GraphicsT=%.2f, AudioT=%.2f, MusicT=%.2f, Beat=%d, Frac=%.2f, " + "[GraphicsT=%.2f, AudioT=%.2f, MusicT=%.2f, Beat=%d, Phase=%.2f, " "Peak=%.2f, Tempo=%.2fx]\n", current_physical_time, current_audio_time, g_music_time, - beat_number, beat, visual_peak, g_tempo_scale); + beat_number, beat_phase, visual_peak, g_tempo_scale); } else { - printf("[GraphicsT=%.2f, AudioT=%.2f, Beat=%d, Frac=%.2f, Peak=%.2f]\n", - current_physical_time, current_audio_time, beat_number, beat, + printf("[GraphicsT=%.2f, AudioT=%.2f, Beat=%d, Phase=%.2f, Peak=%.2f]\n", + current_physical_time, current_audio_time, beat_number, beat_phase, visual_peak); } last_graphics_print_time = current_physical_time; } - // Draw graphics using the graphics frame time and synchronized audio events - gpu_draw(visual_peak, aspect_ratio, (float)current_physical_time, beat); + // Draw graphics using physical time and musical beat time + gpu_draw(visual_peak, aspect_ratio, (float)current_physical_time, + absolute_beat_time, beat_phase); last_frame_time = current_physical_time; // Update audio systems (tracker, synth, etc.) based on audio time -- cgit v1.2.3