aRT (another Ray Tracer) is a little Windows raytracer in C++. Read on for more pics and full source download.

Raytracing is a beautifully elegant way to make an image and makes a lovely break from scanline rendering; although in these days of GPU shaders the distinctions are blurring. I’ve loved raytracers since using Imagine on the Amiga, and built this a couple of years ago. aRT is built in Dev-C++ and uses SDL to show a preview image as it renders. The emphasis here was prettiness, not performance.

Features supported:

• Reflection, refraction - with Monte Carlo methods for reflective/refractive scatter (blurred reflections)
• Diffuse and specular lighting
• Monte Carlo methods for global illumination approximation (diffuse reflections)
• Planes, spheres, triangles, .OBJ models (with normal generation)
• Point/area lights - triangles and spheres can also be emitters
• Versatile scene and material description format, reusable materials
• Texture mapping (bilinear filtered)
• Adaptive super-sampling

Over the years I’ve noticed that a given raytracer definately has a distinctive “look”, due to lighting model variations even across different implementations of the same famous papers. Although there’s nothing ground-breaking here I do love the look of the images aRT produces. Some of the scenes below are converted to aRT’s scene format from other raytracers just so I could compare the look.

Incidentally I haven’t ever seen a method of approximating global illumination as simple as this; it’s not as good as a full radiosity solution but it’s very easy to implement. See RayTracer::GlobalIllumination in RayTracer.cpp.

Time for pretties! All of these scenes are included with the source; scroll down for the download.

Refraction

Global Illumination approximation

Object loading

Gloss

Area lights

Object loading

Just to note, the OBJ loading code isn’t mine; it was found on the net and massaged in. Although hackily integrated it’s nicely encapsulated and provides the raytracer with polygon soup. Alas, I have lost the source of the original loader. If you recognise it, please let me know so I can credit accordingly.

Download (730Kb Zip file - includes binary, example scenes, full source)

Note that you’ll need to install the SDL DevPak to compile; I used version 1.2.8 from Dev-C++’s built-in WebUpdate and it worked fine.