Laguna: Real-time OpenCL Path Tracer

Laguna: Real-time OpenCL Pathtracer

Laguna is a new small OpenCL path tracer (ray tracer) based on a precalculated blocks structure.

OpenCL logo

I tested Laguna on an EVGA GeForce GTX 680 (R301.24) and a MSI Radeon HD 7970 (Cat 12.4) at a resolution of 800×600 and 1920×1080 (you can change settings in the scene.txt file):

1920×1080 fullscreen:

  • GTX 680: 12 FPS
  • HD 7970: 13 FPS

800×600 windowed:

  • GTX 680: 41 FPS
  • HD 7970: 51 FPS

You can download Laguna here (left-click to grab the file):
Download Laguna OpenCL path tracer Version 1.0

Thanks to Arjan van Wijnen (the author of Laguna) for the news!

Laguna: Real-time OpenCL Pathtracer


  • fellix

    At the default SSP value of 1, there’s some weird crosshatched pattern visible, as the rendering progresses. It is like some sort of jittered sampling is being applied in every pass!?

  • Is there a paper published about that new data structure?

  • ca$per

    “KernelManager: Can’t create buffer!” it said.
    AMD 6870 i have, with 12.4 Catalyst (x86).

  • Pap1er

    Same error message as ca$per
    “KernelManager: Can’t create buffer!” it said.
    AMD 6870 i have, with 12.4 Catalyst

  • Antzrhere

    Try setting windows environmental variable GPU_MAX_HEAP_SIZE to a value of 100

    ….Most OpenCL implimentations limit a single buffer to no more than 1/4th of global memory. this is common to all current GPU vendors…however added to this is the fact that on AMD 5xxx and 6xxx series only 50% of global memory is available to use without changing an environmental variable…making the max buffer size 128Mb on a 1GB card…my guess is the 1.3M poly model is too large in this case. By setting GPU_MAX_HEAP_SIZE to 100 you will increase the max buffer size to 256Mb…


  • Anonymous

    When you are using windows XP, update to SP3.

  • ca$per

    Didn’t work. Rebooted and now after launching the demo my PC just hangs. Completely. Reset is needed.

  • lowenz

    This OCL raytracer is far more sensitive to overclock limit than other tests/benchmarks (Furmark based or OCCT).
    So first thing first check the clocks of your card and sei them to default values before screaming for errors!

  • ca$per

    Personally, I have never touched them in my life. So they are at defaults (it’s a Saphire card, so no stock overclocking, unlike some of Asus cards, which do have overclocked models).