preWarm static method

Future<void> preWarm()

Pre-warms the shaders for this effect.

Implementation

static Future<void> preWarm() async {
  if (_cachedProgram != null || _isPreparing) return;
  _isPreparing = true;
  const path =
      'packages/flutter_liquid_glass_widgets/shaders/interactive_indicator.frag';
  const testPath = 'shaders/interactive_indicator.frag';

  try {
    ui.FragmentProgram program;
    try {
      program = await ui.FragmentProgram.fromAsset(path);
    } catch (_) {
      // Fallback for unit tests where package prefix may not be resolved
      program = await ui.FragmentProgram.fromAsset(testPath);
    }
    _cachedProgram = program;

    // Create a 1x1 transparent dummy image to satisfy sampler index 0.
    // toImageSync (not toImage) — synchronous, consistent with
    // LightweightLiquidGlass.preWarm(). For a 1×1 image the GPU cost
    // is negligible and we avoid a 1-frame async initialization delay.
    final recorder = ui.PictureRecorder();
    Canvas(recorder);
    final picture = recorder.endRecording();
    _dummyImage = picture.toImageSync(1, 1);
    picture.dispose();
  } catch (e) {
    debugPrint('[GlassEffect] Pre-warm failed: $e');
  } finally {
    _isPreparing = false;
  }
}