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/gpu/effect.cc | 16 ++++++++++------ src/gpu/effect.h | 13 ++++++++----- src/gpu/effects/flash_effect.cc | 2 +- src/gpu/effects/post_process_helper.h | 13 +++++++------ src/gpu/gpu.cc | 6 ++++-- src/gpu/gpu.h | 3 ++- 6 files changed, 32 insertions(+), 21 deletions(-) (limited to 'src/gpu') diff --git a/src/gpu/effect.cc b/src/gpu/effect.cc index 58e011c..e0a9c24 100644 --- a/src/gpu/effect.cc +++ b/src/gpu/effect.cc @@ -226,7 +226,8 @@ void MainSequence::resize(int width, int height) { } } -void MainSequence::render_frame(float global_time, float beat, float peak, +void MainSequence::render_frame(float global_time, float beat_time, + float beat_phase, float peak, float aspect_ratio, WGPUSurface surface) { WGPUCommandEncoder encoder = wgpuDeviceCreateCommandEncoder(gpu_ctx.device, nullptr); @@ -260,11 +261,12 @@ void MainSequence::render_frame(float global_time, float beat, float peak, // Construct common uniforms once (reused for all effects) CommonPostProcessUniforms base_uniforms = { .resolution = {static_cast(width_), static_cast(height_)}, - ._pad = {0.0f, 0.0f}, .aspect_ratio = aspect_ratio, .time = 0.0f, // Will be set per-effect - .beat = beat, + .beat_time = beat_time, + .beat_phase = beat_phase, .audio_intensity = peak, + ._pad = 0.0f, }; for (const SequenceItem* item : scene_effects) { @@ -564,7 +566,8 @@ void MainSequence::simulate_until(float target_time, float step_rate, for (float t = 0.0f; t < target_time; t += step_rate) { WGPUCommandEncoder encoder = wgpuDeviceCreateCommandEncoder(gpu_ctx.device, nullptr); - float beat = fmodf(t * bpm / 60.0f, 1.0f); + float absolute_beat_time = t * bpm / 60.0f; + float beat_phase = fmodf(absolute_beat_time, 1.0f); std::vector scene_effects, post_effects; for (ActiveSequence& entry : sequences_) { if (t >= entry.start_time) { @@ -575,11 +578,12 @@ void MainSequence::simulate_until(float target_time, float step_rate, for (const SequenceItem* item : scene_effects) { CommonPostProcessUniforms test_uniforms = { .resolution = {static_cast(width_), static_cast(height_)}, - ._pad = {0.0f, 0.0f}, .aspect_ratio = aspect_ratio, .time = t - item->start_time, - .beat = beat, + .beat_time = absolute_beat_time, + .beat_phase = beat_phase, .audio_intensity = 0.0f, + ._pad = 0.0f, }; item->effect->compute(encoder, test_uniforms); } diff --git a/src/gpu/effect.h b/src/gpu/effect.h index ed90ac7..b9709a4 100644 --- a/src/gpu/effect.h +++ b/src/gpu/effect.h @@ -49,16 +49,19 @@ class Effect { // Helper: get initialized CommonPostProcessUniforms based on current dimensions // If aspect_ratio < 0, computes from width_/height_ - CommonPostProcessUniforms get_common_uniforms(float time = 0.0f, float beat = 0.0f, + CommonPostProcessUniforms get_common_uniforms(float time = 0.0f, + float beat_time = 0.0f, + float beat_phase = 0.0f, float intensity = 0.0f, float aspect_ratio = -1.0f) const { return { .resolution = {static_cast(width_), static_cast(height_)}, - ._pad = {0.0f, 0.0f}, .aspect_ratio = aspect_ratio < 0.0f ? static_cast(width_) / static_cast(height_) : aspect_ratio, .time = time, - .beat = beat, + .beat_time = beat_time, + .beat_phase = beat_phase, .audio_intensity = intensity, + ._pad = 0.0f, }; } @@ -130,8 +133,8 @@ class MainSequence { void init_test(const GpuContext& ctx); void add_sequence(std::shared_ptr seq, float start_time, int priority = 0); - void render_frame(float global_time, float beat, float peak, - float aspect_ratio, WGPUSurface surface); + void render_frame(float global_time, float beat_time, float beat_phase, + float peak, float aspect_ratio, WGPUSurface surface); void resize(int width, int height); void shutdown(); diff --git a/src/gpu/effects/flash_effect.cc b/src/gpu/effects/flash_effect.cc index 4357c34..e53cbce 100644 --- a/src/gpu/effects/flash_effect.cc +++ b/src/gpu/effects/flash_effect.cc @@ -77,7 +77,7 @@ void FlashEffect::render(WGPURenderPassEncoder pass, // Animate color based on time and beat const float r = params_.color[0] * (0.5f + 0.5f * sinf(uniforms.time * 0.5f)); const float g = params_.color[1] * (0.5f + 0.5f * cosf(uniforms.time * 0.7f)); - const float b = params_.color[2] * (1.0f + 0.3f * uniforms.beat); + const float b = params_.color[2] * (1.0f + 0.3f * uniforms.beat_phase); // Update uniforms with computed (animated) values const FlashUniforms u = { diff --git a/src/gpu/effects/post_process_helper.h b/src/gpu/effects/post_process_helper.h index 23cde0e..1c649e7 100644 --- a/src/gpu/effects/post_process_helper.h +++ b/src/gpu/effects/post_process_helper.h @@ -8,12 +8,13 @@ // Uniform data common to all post-processing effects struct CommonPostProcessUniforms { - vec2 resolution; - float _pad[2]; // Padding for 16-byte alignment - float aspect_ratio; - float time; - float beat; - float audio_intensity; + vec2 resolution; // Screen dimensions + float aspect_ratio; // Width/height ratio + float time; // Physical time in seconds (unaffected by tempo) + float beat_time; // Musical time in beats (absolute, tempo-scaled) + float beat_phase; // Fractional beat (0.0-1.0 within current beat) + float audio_intensity;// Audio peak for beat sync + float _pad; // Padding for 16-byte alignment }; static_assert(sizeof(CommonPostProcessUniforms) == 32, "CommonPostProcessUniforms must be 32 bytes for WGSL alignment"); diff --git a/src/gpu/gpu.cc b/src/gpu/gpu.cc index e89a2f0..41f5bcf 100644 --- a/src/gpu/gpu.cc +++ b/src/gpu/gpu.cc @@ -381,8 +381,10 @@ void gpu_init(PlatformState* platform_state) { platform_state->height); } -void gpu_draw(float audio_peak, float aspect_ratio, float time, float beat) { - g_main_sequence.render_frame(time, beat, audio_peak, aspect_ratio, g_surface); +void gpu_draw(float audio_peak, float aspect_ratio, float time, + float beat_time, float beat_phase) { + g_main_sequence.render_frame(time, beat_time, beat_phase, audio_peak, + aspect_ratio, g_surface); } void gpu_resize(int width, int height) { diff --git a/src/gpu/gpu.h b/src/gpu/gpu.h index 8c59aee..c7ee89f 100644 --- a/src/gpu/gpu.h +++ b/src/gpu/gpu.h @@ -42,7 +42,8 @@ struct RenderPass { class MainSequence; // Forward declaration void gpu_init(PlatformState* platform_state); -void gpu_draw(float audio_peak, float aspect_ratio, float time, float beat); +void gpu_draw(float audio_peak, float aspect_ratio, float time, + float beat_time, float beat_phase); void gpu_resize(int width, int height); void gpu_shutdown(); -- cgit v1.2.3