I want to create a web-based sci-fi spaceship showcase: open with a wide-angle, low-angle shot from beneath the ship to emphasize its monumental scale; the thrusters should feature realistic emissive glow/heat bloom, with lens flare visible in the frame; as the ship approaches or recedes from the camera, the thruster audio should exhibit a pronounced Doppler shift. For implementation, use Three.js to load the spacecraft model, write a small amount of custom shaders to achieve engine emission and post-processing bloom, and use the Web Audio API to dynamically synthesize audio based on the distance and relative velocity between the ship and the camera. Please provide an example that can run directly in the browser (clear structure, adjustable parameters, and easy model swapping), and explain the camera setup, the post-processing pipeline, and the key points of the Doppler calculation.