säteenjäljitys

Säteenjäljitys, known in English as ray tracing, is a rendering technique used to generate images by simulating the behavior of light. It works by tracing the path of individual light rays from the camera or viewpoint back into the scene. When a ray strikes an object, its behavior is determined by the object's surface properties. This can involve reflection, refraction (bending as it passes through transparent materials), and absorption. The algorithm then recursively traces new rays for these phenomena. For example, a reflected ray will continue its journey, potentially bouncing off other surfaces, until it either hits a light source or a predefined maximum recursion depth is reached.

The primary advantage of ray tracing is its ability to produce highly realistic images with accurate depictions of global illumination effects. This includes soft shadows, realistic reflections on glossy surfaces, and the subtle scattering of light through translucent objects. Unlike simpler rendering methods that approximate these effects, ray tracing calculates them directly from the laws of physics governing light. However, ray tracing is computationally intensive, requiring significant processing power and time, which historically limited its widespread use in real-time applications like video games. Advances in hardware, particularly the development of dedicated ray tracing cores in graphics processing units (GPUs), have made real-time ray tracing feasible in modern gaming and other interactive applications.