Method draw

src/fl/fx/fx_engine.cpp.hpp:96–148

}

bool FxEngine::draw(fl::u32 now, fl::span<CRGB> finalBuffer) {
    mTimeFunction.update(now);
    fl::u32 warpedTime = mTimeFunction.time();

    // Swap audio double-buffers: back → front, then clear back for next frame.
    mAudioFront.swap(mAudioBack);
    mAudioBack.clear();

    // Bump the task scheduler so the audio auto-pump task runs NOW,
    // feeding any pending I2S samples into the Processor before we read levels.
    // Without this, draw() would read stale levels from the previous frame.
    if (mAudioProcessor) {
        fl::task::Scheduler::instance().update();
    }

    // If an audio processor is wired, poll it for one frame per draw cycle.
    if (mAudioProcessor) {
        AudioFrame af;
        af.bass = mAudioProcessor->getBassLevel();
        af.mid = mAudioProcessor->getMidLevel();
        af.treble = mAudioProcessor->getTrebleLevel();
        af.volume = mAudioProcessor->getEnergy();
        af.beat = mAudioProcessor->isVibeBassSpike();
        af.timestamp = now;
        mAudioFront.push_back(af);
    }

    // Build AudioBatch on the stack — shared across both compositor layers.
    // Passes Processor pointer for lazy access to vibe/equalizer/percussion.
    fl::span<const AudioFrame> audioSpan(mAudioFront);
    AudioBatch audioBatch(audioSpan, mAudioProcessor.get());
    const AudioBatch *audioPtr =
        (mAudioFront.empty() && !mAudioProcessor) ? nullptr : &audioBatch;

    if (mEffects.empty()) {
        return false;
    }
    if (mDurationSet) {
        FxPtr fx;
        bool ok = mEffects.get(mCurrId, &fx);
        if (!ok) {
            // something went wrong.
            return false;
        }
        mCompositor.startTransition(now, mDuration, fx);
        mDurationSet = false;
    }
    if (!mEffects.empty()) {
        float speed = mTimeFunction.scale();
        mCompositor.draw(now, warpedTime, finalBuffer, speed, audioPtr);
    }
    return true;
}

} // namespace fl