näkymäfrustumin

Näkymäfrustumi, also known as a view frustum, is a fundamental concept in computer graphics and rendering. It defines the region of space that is visible to a virtual camera. Imagine looking through a window; the view frustum is the three-dimensional shape of that window, outlining what you can see and what is hidden.

The view frustum is typically a truncated pyramid, meaning a pyramid with its top sliced off. This shape is constructed by six planes that form its boundaries. These planes are the near clipping plane, the far clipping plane, and four other planes that define the left, right, top, and bottom edges of the view.

The near clipping plane determines the closest objects that will be rendered. Anything closer to the camera than this plane is clipped and not displayed, preventing issues with rendering extremely close objects or objects within the camera's focal point. Similarly, the far clipping plane sets the maximum distance for visible objects. Objects beyond this plane are also clipped and not rendered, which helps to optimize performance by not processing objects that are too distant to be seen.

The remaining four planes form the sides of the frustum, defining the field of view. These planes are often determined by an aspect ratio (the ratio of width to height of the viewing area) and a vertical field of view angle. Together, these six planes create the boundaries of what the camera can "see," and any geometry that falls outside this volume is excluded from the rendering process. Understanding and correctly defining the view frustum is crucial for efficient and accurate rendering of 3D scenes.