HPWater is a water rendering system for Unity HDRP that implements advanced graphical techniques including ray-traced refraction, volumetric lighting, interactive caustics, and fluid dynamics simulation. The architecture follows Unity's Render Graph API with modular components for different water effects. Key entry points include the main HPWater.shader orchestrator and various C# integration files that hook into HDRP's rendering pipeline. The system processes water rendering through multiple passes: GBuffer encoding for water-specific data, caustic simulation via compute shaders, volumetric light scattering with temporal filtering, refraction calculations, and fluid dynamics for wave propagation. While the core implementation is tightly coupled to Unity's HDRP, it demonstrates solid graphics programming practices.