Open-source hardware ray tracing for Minecraft Java Edition 26.3.
Static brick BVH + dynamic voxel payload — the RT cores traverse a BLAS of 4³ brick AABBs, an intersection shader runs voxel DDA inside each brick, and block changes only rewrite voxel data. No acceleration structure is rebuilt when the world changes.
Status: 0.3.0 prototype. The native Vulkan ray tracer runs on Minecraft's own VkDevice, streams the loaded client chunks into brick voxel data, follows the player camera, presents the ray traced frame in-game, and updates sections when blocks change without touching the acceleration structure. Materials use a small palette instead of textures, and the frame is read back to the CPU before display.
Existing Minecraft RT mods (Radiance, Radiante) trace triangle BLAS built from block geometry, so editing a block means rebuilding or refitting the affected acceleration structures. BrickTrace keeps the acceleration structure static: a 16³ section is 64 bricks of 4³ voxels, each brick is one AABB primitive with a 64-bit occupancy mask, and the voxel payload lives in a plain buffer that can be updated in microseconds.
Minecraft 26.3 JVM
├─ Fabric Mixin (LevelRenderer / GameRenderer)
├─ WorldSnapshot (chunk / block / light / entity / camera)
├─ double-buffered snapshot + dirty-section queue
└─ JNI
└─ Native C++ renderer (Vulkan 1.3, KHR ray tracing)
├─ WorldDB brick pool / material table
├─ ASManager static BLAS per section + per-frame TLAS
├─ RT passes primary + shadow (reflection / GI planned)
├─ Denoise NRD, DLSS RR (planned)
└─ Composite / Present (planned)
| Layer | Representation |
|---|---|
| Section | 16³ blocks, 64 bricks |
| Brick | 4³ voxels, uint64 occupancy mask |
| Voxel | uint32: material 16b · block light 4b · sky light 4b · flags 8b |
| BLAS | one AABB primitive per non-empty brick, built once per section |
| TLAS | visible sections, identity transform, rebuilt per frame |
256×128×256 demo world, 947 non-empty sections, 50,217 bricks, 1920×1080:
| Metric | Value |
|---|---|
| GPU trace rays (primary + shadow) | 0.96 ms/frame (≈1045 fps) |
| Section upload + BLAS/TLAS build | 203 ms (one-off) |
| BLAS + TLAS memory | 3.5 MiB |
| Device | NVIDIA GeForce RTX 5060 Laptop GPU, 7.7 GiB |
Measured with bricktrace-rtbench (timestamp queries around vkCmdTraceRaysKHR). Wall-clock per frame in the benchmark includes a blocking readback to PNG and is therefore not representative.
Requirements:
- Minecraft 26.3 with Fabric Loader 0.20.1+ and Fabric API 0.165.2+26.3
- Windows x64, NVIDIA RTX (tested on RTX 5060), Vulkan 1.3 with ray tracing extensions
- Java 25
Drop bricktrace-0.1.0.jar into .minecraft/mods, start the game. The mod extracts its native library and SPIR-V shaders to .minecraft/config/bricktrace/natives, enumerates the Vulkan device on startup, and logs it:
BrickTrace native device info:
NVIDIA GeForce RTX 5060 Laptop GPU api=1.4.357 AS=1 RT=1 RQ=1 vram=7.7GiB
After joining a world it renders one offscreen RT frame to .minecraft/bricktrace_test_frame.png.
Native (C++20, CMake + MSVC + Vulkan SDK):
cmake -S native -B native/build -G "Visual Studio 18 2026" -A x64
cmake --build native/build --config RelWithDebInfo
# offline renderer: writes bricktrace_frame.png and prints timings
.\native\build\RelWithDebInfo\bricktrace-rtbench.exe --shaders native\build\shaders --out native\build `
--frames 120 --width 1920 --height 1080 --cam 128 96 40 --pitch -0.22Mod (Java 25, Gradle 9.8.2, Loom 1.19):
cd mod
.\gradlew.bat build # -> mod/build/libs/bricktrace-0.1.0.jar
.\gradlew.bat runClient # dev client, no launcher account neededThe jar build copies native/build/RelWithDebInfo/bricktrace_jni.dll and the compiled shaders into the jar, so build the native side first.
mod/ Fabric mod (Java 25, Loom)
native/ C++20 Vulkan renderer, JNI bridge, tools
shaders/ GLSL ray tracing shaders, compiled by CMake via glslang
docs/ architecture, roadmap, environment, prior art, M1 report
scripts/ environment check
- docs/architecture.md — technical design
- docs/roadmap.md — phases and the 14-day M1 plan
- docs/environment.md — Windows toolchain setup
- docs/prior-art.md — prior art and novelty claim
- docs/report-01.md — M1 results
GPL-3.0. Third-party components keep their own licenses.
This project is clean-room: it is not derived from any closed-source Minecraft ray tracing mod, and no such code or assets are included.