MiRay

Physically correct, unbiased rendering engine with advanced layered materials, volumetric transport, and AI-accelerated denoising.

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Downloads

Download the latest standalone portable packages for your operating system:

Platform	Architecture	Download
macOS	Apple Silicon (M1/M2/M3/M4)	MiRay-macOS-arm.zip
Windows	x64 (64-bit)	MiRay-Windows-64.zip

All versions and changelogs are available on the Releases page.

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Features

Rendering Core & Algorithms

• Volumetric Path Tracing (VPT): Physically correct light transport with Next-Event Estimation (NEE), Multiple Importance Sampling (MIS, balance heuristic), and Russian roulette path termination.
• Unified Points, Beams, and Paths (UPBP): Progressive photon mapping integrating Bidirectional Path Tracing (BPT), surface photon mapping (SURF), 3D volumetric photon points (PP3D), 2D photon beams (PB2D), and 1D beam-beam radiance estimates (BB1D / BRE). Robustly resolves challenging specular-diffuse-specular (SDS) paths, water/glass caustics, and volumetric light shafts.
• High-Performance Acceleration: Powered by Intel Embree 4 BVH kernels with multi-threaded, lock-free tile scheduling.
• Low-Discrepancy Samplers: Sobol quasi-Monte Carlo sequence (with precomputed high-dimensional direction matrices) and Halton sampler for rapid low-noise convergence.
• AI Denoising (OIDN 2.x): Integrated Intel OpenImageDenoise with Apple Metal GPU acceleration on macOS Apple Silicon and optimized multi-threaded CPU execution, utilizing Albedo and Shading Normal auxiliary guide buffers.
• Multi-Channel Render Passes (AOVs): Beauty, Albedo, Shading Normals, Depth (Z-depth), Object IDs, Material IDs, and Render Layers.

Layered Materials & Optics (BSDF)

• Hierarchical Layered Architecture: Composable material groups and layers with individual opacity masks, blending modes, and bump mapping.
• Microfacet Specular Models: Trowbridge-Reitz (GGX) and Beckmann distributions with Visible Normal Distribution Function (VNDF) sampling.
• Anisotropic Roughness: Independent roughness and anisotropy parameters with controllable orientation angle and texture mapping.
• Measured Spectral Data & Complex IOR:
  • Direct import of real-world optical measurements (refractiveindex.info formats, filmetrics.com, Maxwell Render .ior, SOPRA .nk).
  • Conversion from spectral wavelengths (CIE XYZ) to RGB color space.
  • Complex Fresnel equations supporting dielectric and conductor ($n, k$) materials.
  • Grazing angle reflection tint (Reflection 90° / edge tint and falloff curve).
• Thin-Film Interference (Iridescence): Physical wave-optics simulation (Airy equations) calculating phase shifts and reflectance across wavelengths based on nanometer film thickness and refractive indices.
• Volumetric Media & Subsurface Scattering (SSS):
  • Volumetric absorption (Beer-Lambert law) and volumetric emission.
  • Subsurface scattering with Henyey-Greenstein phase function (isotropic, forward, or backward scattering).
  • Nested dielectric priority tracking for robust overlapping transparent media (e.g. ice in liquid).
• Surface Displacement & Detail:
  • Tangent-space Normal Mapping.
  • Steep Parallax Mapping / Relief Mapping with binary search refinement and self-shadowing.
  • Oren-Nayar and Lambertian diffuse models with diffuse translucency / transmission.
• Double-sided Geometry: Configurable two-sided or single-sided surface shading.

Lighting & Environment

• Image-Based Lighting (IBL): High Dynamic Range (HDRI / EXR) spherical environment maps with 360° horizontal/vertical rotation, scale, and MIS sampling.
• Multiple Background Modes: Environment projection, transparent alpha cutout, planar images, spherical images, and gradient backdrops (radial, vertical, horizontal).
• Analytic & Area Lights:
  • Directional Sun light with tunable angular diameter for realistic soft shadows.
  • Spherical / Point lights with physical radius and inverse-square falloff.
  • Emissive Geometry lights with CDF triangle importance sampling.
• Virtual Studio Floor: Ground plane with shadow catcher and tunable glossy reflections.

Camera & Optics

• Lens Projections: Perspective, Orthographic, Spherical (360° Equirectangular panorama), Cylindrical, and Fisheye.
• Physical Depth of Field (DoF): Thin-lens camera model with f-stop, interactive click-to-focus distance, polygonal diaphragm aperture (3–32 blades), and bokeh rotation.
• Snapshots & Interpolation: Scene state snapshots capturing camera pose, object transforms, materials, visibility, and lighting, with smooth transition interpolation and motion blur.

Asset Formats & Ecosystem

• 3D Geometry Import: glTF / GLB, FBX, OBJ, Blender (.blend), Collada (.dae), 3DS, STL, PLY, DXF (via Assimp).
• Image I/O: OpenEXR, Radiance HDR, TIFF, PNG, JPEG, PSD, BMP, PFM.
• Color Management: Accurate color space conversion and ICC profile handling via Skia CMS (skcms).
• Asset Library: Bundled material presets, studio environments, and Poly Haven CC0 HDRIs and assets.

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Quick Start

The repository includes a root Makefile with cross-platform targets for common development workflows:

# 1. Install Conan dependencies, configure CMake, and build
make build

# 2. Run unit test suites
make test

# 3. Package standalone application
make app

# 4. Launch the compiled MiRay application
make run

# 5. Generate native IDE project (Xcode on macOS, Visual Studio on Windows)
make project

# 6. Clean build outputs (bin/, tmp/)
make clean

Build Modifiers

You can select target architecture and configuration via modifiers:

make arm release build   # macOS Apple Silicon (RelWithDebInfo)
make intel debug build   # Intel/AMD x86_64 (Debug)
make debug test          # Run tests with Debug configuration

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IDE Projects (Xcode & Visual Studio 2022)

To generate native IDE project files (auto-detects host CPU architecture and platform by default):

make project                # Generate Xcode project (macOS) or VS solution (Windows) in Debug
make release project        # Generate with RelWithDebInfo configuration
make both project           # Generate with both Debug and RelWithDebInfo dependencies
make intel project          # Force Intel/x64 architecture
make arm project            # Force Apple Silicon architecture

• macOS (Xcode): open tmp/MiRay.xcodeproj
• Windows (Visual Studio 2022): start tmp\MiRay.sln

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For the full, in-depth documentation, please see: docs/build.md

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Repository Structure

├── CMakeLists.txt         # Root Modern CMake 3.28+ project configuration
├── conanfile.py           # Conan 2 dependency specification and deployment logic
├── conan/                 # Conan profiles (mac-arm, mac-x64, win-x64)
├── Core/                  # Rendering core, math, materials, integrators, primitives
├── Core.Tests/            # GoogleTest unit tests for Core
├── Shared/                # Utilities, logging, thread pool, shared models
├── FormatModels3D/        # 3D model importer plugin (Assimp)
├── MiRay/                 # Qt GUI frontend, main window, render view, QML assets
├── Resources/             # Scene library, shapes, materials, and preview assets
├── tools/                 # App bundling and build configs
│   ├── mac/               # bundle.sh (macOS app bundling)
│   └── win/               # bundle.cmd (Windows app bundling), version.rc.in, qt.conf
├── docs/
│   └── build.md           # Comprehensive build and distribution documentation
└── Makefile               # Development CLI shortcuts

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License

This project is licensed under the MIT License - see the LICENSE file for details.