# Odin + SDL3 GPU cubes (Vulkan only)

Small starter project in Odin that opens an SDL3 window, renders several 3D cubes with the SDL3 GPU API, and uses a Vulkan-only backend with SPIR-V shaders.

## Controls

- Left mouse drag: orbit camera
- Middle mouse drag: pan
- Mouse wheel: zoom in/out
- `W/A/S/D`: move camera target
- `Esc`: quit

## Requirements

- [Odin compiler](https://odin-lang.org/)
- SDL3 installed on your system (for runtime linking)
- Vulkan-capable GPU/driver with SDL3 Vulkan support
- `glslc` (from `shaderc`) to compile GLSL to SPIR-V

On macOS with Homebrew:

```bash
brew install odin sdl3 shaderc
```

## Build and run

Quick start:

```bash
./run.sh
```

The script compiles shaders, sets `VK_ICD_FILENAMES` to MoltenVK if available,
adds `/opt/homebrew/lib` to `DYLD_FALLBACK_LIBRARY_PATH`, and runs the app.

Compile shaders first:

```bash
glslc -fshader-stage=vert shaders/cubes.vert.glsl -o shaders/cubes.vert.spv
glslc -fshader-stage=frag shaders/cubes.frag.glsl -o shaders/cubes.frag.spv
```

From the project root:

```bash
odin run src -out:bin/cubes_gpu
```

Or build only:

```bash
odin build src -out:bin/cubes_gpu
```

## Notes

- Shaders source files are `shaders/cubes.vert.glsl` and `shaders/cubes.frag.glsl`.
- Runtime shader binaries are `shaders/cubes.vert.spv` and `shaders/cubes.frag.spv`.
- The app forces SDL3 GPU driver `vulkan` and exits if Vulkan is unavailable.