onCapture = (error, snapshot) => {
  const { captureRequested } = this.state;
  if (error) console.error(error);
  else doSomethingWithSnapshot(snapshot);
  this.setState({ captureRequested: false });
};

render () {
  return <View>
    <Button onPress={() => this.setState({ captureRequested: true })}>CAPTURE</Button>
    <Text>...<Text>
    <Text>...<Text>
    <Text>...<Text>
    {!captureRequested ? null : <AutoCaptureGLThing {...whateverProps} onCapture={this.onCapture} />}
  </View>;
}