Vulkan Screen-Space Reflections

Vulkan application that showcases the capabilities of Screen-Space Reflections. It offers two algorithms to resolve reflections:

• 3D Ray Marching - 2011, Souta et. al
• Perspective-correct DDA - 2014, Mara et. al

The Deferred Rendering pipeline consists of the following steps:

1. Shadow pass - See shadow_map.{vert|frag}
2. Offscreen pass - See offscreen.{vert|frag}
3. Fullscreen pass - See fullscreen.{vert|frag}

During the Offscreen pass, the G-Buffer is constructed with the material and shadowing properties. Subsequently, this data is leverage to determine whether the pixel microfacet is reflective and a single SSR ray is traced. The reflected colour is dynamically constructed from the G-Buffer. The shared file shade.glsl contains the bulk of the PBR computation.

Pipeline Overview

Project Structure

vulkan-ssr/
├── assets-bake/           # Asset baking source code
├── assets-src/            # Static assets (to be baked)
├── third-party/           # Bundled third party libraries
├── util/glslc.lua         # Compile-time utility to compile shaders with google/shaderc 
├── ssr/                   # Application source code
    ├── shaders/           # GLSL shaders
├── vkutils/               # Application source code
├── playback/              # CSV playback files
├── premake5.lua           # Premake 5 configuration
├── premake5(.*)           # Bundled Premake 5 executables
├── third-party.md         # Third party libraries' licenses
└── README.md              # Project README

Build - Make

./premake5 [enable-diagnostics={true|false}] gmake2
make [config={debug_x64|release_x64}]

The enable-diagnosticts parameters default to true, and config defaults to debug_x64. This applies to all platforms.

Build - Visual Studio

./premake5.exe [enable-diagnostics={true|false}] vs2022

Open generated .sln project file.

Build - Xcode

./premake5.apple [enable-diagnostics={true|false}] xcode4

Open generated Xcode project.

Run

bin/assets-bake-{target}.exe
bin/ssr-{target}.exe <scene-name> [tag]

Executables have .exe extension for all platforms, but binaries are platform-specific.

Baking is required to be run successfully before application.

The scene-name parameter is required and the set of possible values is assets/<scene_name>. The tag parameter is used as a suffix to identify output files.

Controls

Key(s)	Action
Right Click	Toggle camera rotation with mouse
W A S D E Q	Move camera around
I / L	Reset camera to initial/light position
Shift / Ctrl	Slow/fast speed modifiers for camera controls
P	Render current frame to output .png
Camera / Light UI	Set different parameters of the camera and single light system
Shading UI	Control different aspects of the shading model
SSR UI	Control different aspects of the Screen-Space Reflections method
Benchmarks UI	Performs benchmarks, with optional playback file
Utilities UI	Take Screenshot and potentially other utilities
Esc	Close application

Technologies

• C++: >= C++23
• Premake: 5.0.0 (Bundled)
• Vulkan: >= 1.2.0 (Bundled headers)
• Volk: 1.3.295 (Bundled)
• Vulkan Memory Allocator (VMA): 3.1.0 (Bundled)
• GLSL: 460
• GLM: 0.9.9 (Bundled)
• GLFW: 3.4 (Bundled)
• ImGui: 1.90.8 (Bundled)
• stb_image: v2.29 (Bundled)
• stb_image_write: v1.16 (Bundled)
• Native File Dialog Extended: v1.2.0 (Bundled)

A few additional supporting libraries are leveraged. Files were selectively bundled as needed.

See third-party.md for licensing and attributions.

Assets

Attributions to third-party assets are detailed in the respective assets-src/<scene-name>/README.txt.

TODOs

• Refactor benchmark.cpp to use delta Δt instead of absolute frame time
• Automatically detect changes to shade.glsl for shader recompilation