Live Performance Architecture in TouchDesigner

# master_controller.py — module extension on the master_controller Base COMP

class MasterController:
    def __init__(self, owner_comp):
        self.owner = owner_comp
        self.current_scene = 0
        self.scene_comps = [op(f'/project1/scenes/scene_{i+1:02d}') for i in range(6)]
        self.transition_duration = 2.0  # seconds
        self._active_transition = False

    def go_to_scene(self, index, duration=None):
        """Switch to scene by index (0-based) with optional cross-fade duration."""
        if index == self.current_scene:
            return
        if duration is None:
            duration = self.transition_duration

        prev = self.current_scene
        self.current_scene = index

        # Enable new scene's Cook flag
        self.scene_comps[index].allowCooking = True

        # Cross-fade via LFO CHOP controlling Switch TOP blend
        lfo = op('/project1/output/crossfade_lfo')
        lfo.par.period = duration
        lfo.par.Start.pulse()

        # Disable previous scene after transition completes
        run("args[0].allowCooking = False", self.scene_comps[prev],
            delayFrames=int(duration * project.cookRate) + 5)

        print(f'[MASTER] Scene {prev+1} → Scene {index+1} ({duration:.1f}s fade)')

    def update_midi(self, cc, value):
        """Route incoming MIDI CC to parameter — called from MIDI In CHOP callback."""
        mapping = op('/project1/midi/mapping')
        for row in range(mapping.numRows):
            if int(mapping[row, 'cc']) == cc:
                target_op  = op(mapping[row, 'op'])
                target_par = mapping[row, 'par']
                min_val    = float(mapping[row, 'min'])
                max_val    = float(mapping[row, 'max'])
                mapped     = min_val + (value / 127.0) * (max_val - min_val)
                setattr(target_op.par, target_par, mapped)
                break

# /project1/cue_system/cue_runner Script DAT

current_cue = 0
auto_timer = None

def go(dat):
    """Advance to next cue — called by MIDI button or keyboard shortcut."""
    global current_cue, auto_timer
    cue_table = op('/project1/cue_system/cue_table')
    if current_cue >= cue_table.numRows - 1:
        return

    current_cue += 1
    row = cue_table[current_cue]
    scene_idx = int(row['scene']) - 1
    duration  = float(row['duration'])
    trigger   = row['trigger'].val

    mc = op('/project1/master_controller').ext.MasterController
    mc.go_to_scene(scene_idx, duration)

    # Schedule auto-advance if specified
    if trigger.startswith('auto:'):
        seconds = float(trigger.split(':')[1])
        auto_timer = run("op('/project1/cue_system/cue_runner').go(None)",
                         delaySeconds=seconds)

    print(f'[CUE] {current_cue}: Scene {scene_idx+1}, fade={duration}s')

# Startup Execute DAT — runs once on first frame
def frameStart(frame):
    if frame > 1: return
    for top in root.findChildren(type=topType, depth=10):
        top.viewer = False

last_pulse = 0.0

def onPulse(channel, sampleIndex, val, prev):
    global last_pulse
    last_pulse = absTime.seconds

def frameEnd(frame):
    if absTime.seconds - last_pulse > 1.0:
        print('WARNING: Watchdog pulse missed — checking state')
        # Attempt recovery: re-enable cooking on stuck OPs
        for comp in op('/project1/scenes').children:
            comp.allowCooking = comp == op(f'/project1/scenes/scene_{master_controller.current_scene+1:02d}')

def pre_show_check():
    checks = []
    import psutil, subprocess

    # GPU temperature
    result = subprocess.run(['nvidia-smi', '--query-gpu=temperature.gpu',
                             '--format=csv,noheader'], capture_output=True, text=True)
    gpu_temp = int(result.stdout.strip())
    checks.append(('GPU temp < 75°C', gpu_temp < 75, f'{gpu_temp}°C'))

    # Available VRAM
    result = subprocess.run(['nvidia-smi', '--query-gpu=memory.free',
                             '--format=csv,noheader,nounits'], capture_output=True, text=True)
    vram_free = int(result.stdout.strip())
    checks.append(('VRAM > 4000 MB free', vram_free > 4000, f'{vram_free} MB'))

    # Cook rate
    actual_fps = 1.0 / max(me.cookTime, 0.001)
    checks.append(('Cook rate ≥ 58 fps', actual_fps >= 58, f'{actual_fps:.1f} fps'))

    # All scenes present
    for i in range(6):
        sc = op(f'/project1/scenes/scene_{i+1:02d}')
        checks.append((f'Scene {i+1} exists', sc is not None, ''))

    for label, passed, detail in checks:
        status = 'PASS' if passed else 'FAIL'
        print(f'  [{status}] {label} {detail}')