a ray tracer with both CPU and GPU acceleration capabilities implemented in rust, just a fun project, do it for learning purpose

with

• Path tracing with Monte Carlo sampling
• Materials: Lambertian diffuse, metal, dielectric (glass)
• Camera with depth of field and adjustable field of view
• Cross-platform GPU acceleration using wgpu
• PPM image output format

Prerequisites

• just your shitty laptop, that have GPU with Vulkan, Metal, or DirectX 12 support (if you dont have then use your poor cpu)

Building

CPU-only version

cargo build --release

With GPU acceleration

cargo build --release --features gpu

Running

Basic usage

cargo run --release

With GPU acceleration

cargo run --release --features gpu -- --gpu

Saving to a file

cargo run --release -- -o output.ppm

Using GPU acceleration and saving to a file

cargo run --release --features gpu -- --gpu -o output.ppm

Command Line Options

• --gpu or -g: Enable GPU acceleration (requires compilation with --features gpu)
• -o or --output followed by a filename: Save the render to a PPM file

Performance

ofc GPU-accelerated version can be significantly faster than the CPU version, especially for high sample counts and complex scenes. Performance will vary based on your specific GPU.

Configuration

You might want to adjust rendering parameters in main.rs for faster preview:

// Camera setup
let mut cam = Camera::new();
cam.aspect_ratio = 16.0 / 9.0;
cam.image_width = 1200;
cam.samples_per_pixel = 500; // Lower this to 100-200 for faster rendering
cam.max_depth = 50;
cam.vfov = 20.0;
cam.lookfrom = Point3::new(13.0, 2.0, 3.0);
cam.lookat = Point3::new(0.0, 0.0, 0.0);
cam.vup = Vec3::new(0.0, 1.0, 0.0);
cam.defocus_angle = 0.6;
cam.focus_dist = 10.0;
cam.use_gpu = use_gpu; // This is set from command-line args

Implementation Details

• CPU rendering is implemented in pure Rust
• GPU rendering is implemented using wgpu for cross-platform compatibility (Metal on macOS, Vulkan on Linux, DirectX 12 on Windows)
• The ray tracing algorithm is implemented as a compute shader in WGSL