Everyone needs to write a raytracer, right?
So this is a simple real-time raytracer written in Java with a Swing-based interactive UI. It's CPU-only, doesn't use OpenGL, and doesn't use GPU acceleration. Move the camera with WASD, zoom with = and -, and quit with Q or ESC. The scene features 5 colored spheres arranged in a circle, a ground plane, and multiple light sources (point, directional, and ambient).
The project is just a prototype, and doesn't do proper double buffering. That's why there can be some artifacts during redrawing.
- Real-time multi-core rendering,
- Interactive camera movement and zoom,
- Scene with multiple spheres, ground, and lights.
- W, A, S, D: Move camera
- = / -: Zoom in/out
- Q or ESC: Quit
- [ and ]: Rotate camera
- Spheres: Ray/sphere hits are solved from the quadratic equation of the sphere surface; the closest valid t is chosen and the surface normal is the vector from the center to the hit point.
- Rectangles: A plane hit is found via the rectangle normal; the ray is discarded if parallel, outside the near/far t range, or if the projected hit falls outside the half-width/half-height extents along the rectangle’s basis axes.
- Shadows: For each light a shadow ray is cast from the visible point toward the light (or along the light direction); if any object intersects before the light, that light contributes nothing.
- Light & shading: Ambient adds constant intensity, while point and directional lights add diffuse (dot product) and Phong-style specular highlights; reflective materials blend the local color with a recursively traced reflection ray.
- Reflection: The reflection ray is computed by mirroring the view vector around the surface normal; its color contribution is recursively traced and mixed with the local shading by the material’s reflectivity.
./gradlew shadowJar
java -jar build/libs/jtracer-1.0-SNAPSHOT-all.jar
Tested only on Linux X11 + KDE.
Public domain.
Gabriel Gambetta (https://gabrielgambetta.com)