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Paper

Performance Profiling of Vulkan-based Ray Tracing Renderers on Mobile Platforms

July 2025 Taekgeun You, Sungho Yun, Sehee Cho, Woong Seo and Insung Ihm Journal of the Korea Computer Graphics Society, Vol. 31, No. 3, pp. 171–181
#Real-Time Rendering #Ray Tracing #Ray Query #Mobile #Vulkan

Abstract

The emergence of high-performance desktop GPU has enabled ray tracing techniques to be widely used in real-time rendering, including 3D gaming applications. However, applying real-time ray tracing on moblie devices remains challenging due to power consumption, thermal constraints, and limited resources. In this paper, we developed a Vulkan-based optimized renderer for real-time ray tracing on mobile platforms and analyzed its performance. The renderers are categorized into two types: a full ray tracing renderer and a rasterization-based hybrid ray tracing renderer. To achieve optimal implementation, we applied the ray tracing pipeline and ray query extension to each renderer and evaluated their performance. Furthermore, to reduce the shading cost caused by shadow rays in scenes with multiple lights, we adopted an optimization technique that restricts the shading based on the extent of each light’s influence. In this context, maintaining the light’s influence as small as possible while preserving appropriate intensity is critical. To this end, we propose a new attenuation function and assess its performance when applied.

Key Contributions

  1. Mobile ray tracing renderer implementation
  2. Ray tracing pipeline and ray query comparison
  3. Multi-light shading optimization

Renderering Methods

Full Ray Tracing
Full Ray TracingUses ray tracing or ray query as the primary rendering method.
Hybrid
HybridPerforms deferred rasterization first, then applies ray tracing or ray query for selected effects.
Hybrid Shadowmap
Hybrid ShadowmapUses the hybrid approach but replaces ray-traced shadow rendering with shadow mapping.

Renderering Pipelines

Hybrid Pipeline
Hybrid PipelineUses ray tracing or ray query as the primary rendering method.
Hybrid Shadowmap Pipeline
Hybrid Shadowmap PipelinePerforms deferred rasterization first, then applies ray tracing

Extending the Light Attenuation Function

f(x)={1ax2+bx+1,if 0<x<αdmax⁡,h(x−αdmax⁡)2+1β,if αdmax⁡<x<dmax⁡,a=(1−1β)1αdmax⁡,b=−2(1−1β)1αdmax⁡,h=1(1−α)2dmax⁡2(1γ−1β).\begin{aligned} f(x) &= \begin{cases} \dfrac{1}{a x^2 + b x + 1}, & \text{if } 0 < x < \alpha d_{\max}, \\[8pt] h\left(x-\alpha d_{\max}\right)^2+\dfrac{1}{\beta}, & \text{if } \alpha d_{\max} < x < d_{\max}, \end{cases} \\[12pt] a &= \left(1-\dfrac{1}{\beta}\right) \dfrac{1}{\alpha d_{\max}}, \\[8pt] b &= -2\left(1-\dfrac{1}{\beta}\right) \dfrac{1}{\alpha d_{\max}}, \\[8pt] h &= \dfrac{1}{(1-\alpha)^2 d_{\max}^2} \left( \dfrac{1}{\gamma}-\dfrac{1}{\beta} \right). \end{aligned}
Attenuation Function Control
Attenuation Function ControlAttenuation function control using alpha, beta, and gamma parameters.

Summary

  • Performance analysis of various ray-tracing rendering techniques on mobile platforms
  • Hybrid ray-tracing renderers generally outperform full ray-tracing renderers.
    • However, the performance advantage of hybrid ray tracing decreases as the number of triangles increases.
  • Using an any-hit shader significantly increases traversal costs in the ray-tracing pipeline.
    • Some any-hit effects can be reproduced using a hybrid ray-tracing approach.
  • Ray queries generally outperform the ray-tracing pipeline.
  • A new attenuation function is proposed to effectively balance performance and visual quality.