A Vulkan implementation of real-time PBR renderer
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README.md

Laugh Engine

A Vulkan implementation of real-time PBR renderer.


Results

Paper Mill Factory
Mon Valley Canyon

glTF Support

  • glTF, also called the GL Transmission Format, it is a runtime asset dilivery format for GL-based applications. It supports common functionalities of 3D applications such as geometry, texture, skin, and animation. It also allows extension, for example, I used the FRAUNHOFER_materials_pbr extension to load PBR textures.
  • It aims to form a standard/common format for runtime asset dilivery/exchange. In my opinion, it has better documentation than FBX and possess some abilities that some other file formats don't (e.g. scene hierarchy, skin, animation). I believe, if it gets popular, it will be a great convenience to both application developers and artists because less effort will be required to perform application-specific conversion on file formats.
  • In order to show my support, I added glTF support to Laugh Egine. It is now able to load geometry and material data from glTF files.
  • Below are some screen shots of 3D models loaded from glTF files. Thanks to Sketchfab for providing these glTF assets.
Microphone Centurion

Overview

Performance Analysis

  • Precomputation performance

    • It is not real-time but fast enough to be used for interactive editting
    • The increase of execution time from 128x128 to 256x256 is very small. Probably the GPU is not saturated at that time.
    Envrionment Prefiltering BRDF LUT Baking
  • PBR vs. Blinn-Phong

    • PBR using IBL only
    • Blinn-Phong was tested using two point light sources
    • Framebuffer resolution was 1920x1080 with no AA
    • Bloom was on
    • The scene with a Cerberus pistol in it was used for benchmark
    • Basically no addtional cost by using PBR over Blinn-Phong but we get much better quality

  • Anti-Aliasing

    • Increases visual quality (smoother edges and more accurate shading)
    • Decreases performance. For 2xAA, 4xAA, and 8xAA, frame time is increased by 31%, 70%, and 173%, respectively when compared to no AA
    • I did custom resolve in a fragment shader because Laugh Engine is deferred. Right now, I am doing lighting computation on each sample so it is basically SSAA not MSAA. I tried to perform computation only once per material type but the performance was much worse because the code that figures out distinct material types is expensive causes a lot of branching (frame time goes up to 8ms for 4xAA). So I will stick to the current scheme until I find a better way.
    1xAA 2xAA
    4xAA 8xAA

Build Instruction

  • Install LunarG Vulkan SDK
  • If you have Visual Studio 2015, the solution should build out of the box
  • To run the program, you will need to copy the .dlls to executable path or system paths
  • Builds on other platforms are not supported yet

Third-Party Credits

References:

Libraries

Assets