Metallic

Metallic is a rendering playground for modern GPU-driven rendering experiments.

• macOS uses the original Metal renderer with scene loading, mesh shaders, visibility-buffer rendering, ray-traced shadows, atmosphere, and an ImGui debug UI.
• Windows uses the newer backend-agnostic RHI path with a Vulkan 1.4 preview renderer and shared pipeline asset system.
• A standalone PipelineEditorTool lets you inspect and edit pipeline JSON graphs outside the renderer.

Most of the codebase is authored with heavy assistance from Claude Opus 4.6 and OpenAI GPT-5.3 Codex.

Backend Status

Platform	Backend	Status
macOS (Apple Silicon)	Metal	Main renderer path
Windows	Vulkan 1.4	Bootstrap / preview path

Linux is not a supported target right now.

Features

Metal renderer

• Scene loading and rendering for Sponza
• Vertex forward, mesh shader forward, visibility buffer, and meshlet debug modes
• Meshlet frustum culling, backface cone culling, and GPU-driven culling
• Ray-traced shadows on the Metal path
• Atmospheric scattering sky rendering
• TAA, auto exposure, tonemapping, and per-pass debug UI
• FrameGraph execution with optional Graphviz DOT export

Shared infrastructure

• Backend-agnostic RHI layer under Source/RHI/
• Data-driven pipeline assets in Pipelines/*.json
• Slang shader compilation for Metal and Vulkan targets
• Runtime shader reload (F5) and pipeline asset reload (F6) on the Metal renderer
• Tracy profiling and spdlog logging

Windows Vulkan preview

• GLFW + Vulkan bootstrap through the shared RHI
• Slang-to-SPIR-V compilation at startup
• Preview post stack driven by Pipelines/vulkan_preview.json
• Sky preview path when atmosphere textures and the sky shader are available
• Triangle fallback path when preview resources are unavailable

Pipeline editor tool

• Standalone ImGui + imnodes graph editor
• Loads and saves pipeline assets from Pipelines/
• Visualizes pass/resource dependencies and validates the DAG

Repository Layout

Source/
  main.cpp                     Metal renderer entry point
  main_vulkan.cpp              Windows Vulkan preview entry point
  Rendering/                   Frame graph, passes, shader management, frame context
  RHI/                         Shared interfaces and backend implementations
  PipelineEditor/              Shared pipeline asset, registry, and builder code
  Platform/                    Apple-specific runtime and bridge code
  Scene/                       Scene graph and inspector UI
  Asset/                       Mesh, meshlet, and material loading

Tools/
  PipelineEditor/              Standalone pipeline editor executable

Shaders/                       Slang and native MSL shader sources
Pipelines/                     JSON pipeline assets
Asset/                         Runtime textures, models, and atmosphere data
External/                      Vendored third-party dependencies
cmake/                         Build helpers, including Slang setup

Building

Clone with submodules:

git clone --recursive <repo-url>
cd metallic

If you already cloned without submodules, sync the profiler dependency with:

git submodule update --init --recursive External/microprofile

If External/slang is missing, CMake will try to use:

1. -DSLANG_ROOT=<sdk-root>
2. SLANG_ROOT
3. SLANG_DIR
4. External/slang

macOS / Metal

Requirements:

• Apple Silicon Mac
• Xcode command line tools

cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug
cmake --build build --target Metallic -j$(sysctl -n hw.ncpu)
./build/Source/Metallic

Notes:

• The macOS build copies Shaders/, Asset/, and Pipelines/ next to the executable.
• The standalone pipeline editor is also available on macOS:

cmake --build build --target PipelineEditorTool -j$(sysctl -n hw.ncpu)
./build/Tools/PipelineEditor/PipelineEditorTool

Windows / Vulkan

Requirements:

• Visual Studio 2022 or another CMake-capable MSVC toolchain
• Vulkan SDK
• A Slang SDK if External/slang is not populated

cmake -S . -B build -DSLANG_ROOT=D:/path/to/slang
cmake --build build --config Debug --target Metallic
build/Source/Debug/Metallic.exe

Standalone editor on Windows:

cmake --build build --config Debug --target PipelineEditorTool
build/Tools/PipelineEditor/Debug/PipelineEditorTool.exe

Notes:

• The Windows renderer is currently a preview path, not feature parity with the Metal renderer.
• It exercises the shared RHI, shader compiler, frame graph, and pipeline asset system.

Runtime Controls

Metal renderer:

• F5: rebuild shaders
• F6: reload pipeline JSON assets
• G: export framegraph.dot
• ImGui renderer panel: switch render modes and toggle culling, TAA, RT shadows, and sky settings

Pipeline Assets

Pipeline graphs live in Pipelines/ and are described as JSON:

• resources: declared textures/buffers
• passes: pass type, inputs, outputs, enabled state, side-effect flag, and pass config

Current in-tree examples include:

• Pipelines/forward.json
• Pipelines/meshlet_debug.json
• Pipelines/visibility_buffer.json
• Pipelines/vulkan_preview.json

The shared loader validates missing resources, duplicate producers, and graph cycles before execution.

Dependencies

Library	Purpose
metal-cpp	Metal C++ wrapper on macOS
Vulkan SDK + VMA	Windows Vulkan backend
GLFW	Window creation and input
Dear ImGui	Debug UI
imnodes	Pipeline editor node graph UI
Slang	Shader authoring and code generation
microprofile	Lightweight frame scope profiling
Tracy	CPU/GPU profiling
spdlog	Logging
nlohmann/json	Pipeline asset serialization
meshoptimizer	Meshlet generation and culling support
cgltf / stb_image	Asset loading
MathLib	HLSL-style math helpers