Disney Photon Beam & Photon Mapping Rendering (DirectX12 with RTX)

This project implements volumetric participating media rendering using Disney's Photon Beam algorithm and traditional Photon Mapping, fully utilizing DirectX12 and NVIDIA RTX features. It forms part of my graphics programming portfolio, showcasing advanced global illumination techniques in real-time rendering.

📽️ Demo Video and Images

🔗 YouTube Showcase (DirectX12)

Beam and Sruface Photon

Surface Photon Only

Beam Only

Beam and Photon Sampling Visualization

Different Parameter Effects - Adjusting scattering coefficient, extinct coefficient and HG symmetric factor

🔗 Project Links

• DirectX12 Implementation (This Repository)
  https://github.com/donguklim/DirectX12PhotonBeam

• Vulkan Implementation (Based on NVIDIA Ray-Tracing Tutorial)
  https://github.com/donguklim/vk_raytracing_tutorial_KHR/tree/master/photon_beam

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✨ Features

🌌 Photon Mapping

• Simulates photon interactions on surfaces via ray tracing.
• Stores radiance sampled from photon hits on surfaces.

💫 Photon Beam

• Simulates photon beams through participating media like air.
• Samples scattering and extinction based on beam paths and density.
• Produces realistic volumetric lighting effects.

🔁 Scattering Modes

Mode	Scattering Direction
Uniform	Evenly scattered in all directions
Forward	Scattered near beam’s previous direction
Backward	Scattered opposite to the beam’s direction

🌈 Dynamic Light Simulation

• Light reflection is controlled by random seed updates.
• To avoid flickering, linear interpolation blends two seed-based frames.
• Adjusting seed interval simulates underwater wave-like effects.

🎞️ Example of dynamic lighting:
Jump to 20:00 in demo video

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📚 References

• Photon Mapping

  • Jensen, Henrik. (2001). A Practical Guide to Global Illumination using Photon Maps.

• Photon Beam

  • Derek Nowrouzezahrai, Jared Johnson, Andrew Selle, Dylan Lacewell, Michael Kaschalk, Wojciech Jarosz. A programmable system for artistic volumetric lighting. ACM Transactions on Graphics (Proceedings of SIGGRAPH), 30(4):29:1–29:8, August 2011.
  • Wojciech Jarosz, Derek Nowrouzezahrai, Iman Sadeghi, Henrik Wann Jensen. A comprehensive theory of volumetric radiance estimation using photon points and beams. ACM Transactions on Graphics (Presented at SIGGRAPH), 30(1):5:1–5:19, January 2011.

• BRDF Sampling

  • https://www.astro.umd.edu/~jph/HG_note.pdf   [pdf file backup]
  • https://agraphicsguynotes.com/posts/sample_microfacet_brdf/   [webpage backup as pdf file]
  • https://schuttejoe.github.io/post/ggximportancesamplingpart1/   [webpage backup as pdf file]

Third Party Libraries

• "Introduction to 3D Game Programming with DirectX 12" book - Sample codes in Common folder.

  • Common/ - The original codes have been modified.

• Microsoft Official DirectX header files

  • third-party/directx-headers

• tiny gltf - stb_image.h, stb_image_write.h, json.hpp, tiny_gltf.h

  • third-party/tiny-gltf

• Microsoft DirectX Samples - DirectXRaytracingHelper.h DXSampleHelper.h

  • third-party/microsoft-directx-graphics-samples

📌 Notes

• Specular surfaces are handled using plain ray tracing, as photon techniques are insufficient in those cases.
• Parameters such as light hue, intensity, and air murkiness control the scattering visuals and beam density.

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📁 Related Portfolio

For more rendering and simulation projects, check out my main portfolio repository:
🔗 Graphics Portfolio

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