Strålspårning

Strålspårning, or ray tracing in English, is a rendering technique used in computer graphics to produce highly realistic images. It simulates the physical behavior of light by tracing the path of individual light rays as they travel from a camera, through a scene, and interact with objects. When a ray hits a surface, its behavior is determined by the material properties of that surface. This can involve reflection, where the ray bounces off in a new direction, refraction, where the ray bends as it passes through a transparent material, or absorption, where the ray's energy is taken in by the material.

The core idea is to reverse the process of how light reaches a viewer. Instead of simulating every light source and how its rays illuminate the scene, ray tracing starts from the viewpoint of the camera and traces rays backward into the scene. For each pixel on the screen, a ray is cast. If this ray intersects an object, further rays are generated to simulate reflections, refractions, and shadows. These secondary rays travel back towards light sources or bounce further within the scene, accumulating color and light information.

This physically-based approach allows ray tracing to accurately model complex lighting phenomena such as soft shadows, realistic reflections on curved surfaces, caustics (light patterns formed by refraction or reflection), and depth of field. While computationally intensive, advancements in hardware and algorithms have made real-time ray tracing increasingly feasible, leading to its adoption in video games and professional visualization applications for enhanced visual fidelity.