Clipspacekoordinaatti

Clipspacekoordinaatti, also known as normalized device coordinates (NDC), is a coordinate system used in computer graphics during the projection transformation stage of the rendering pipeline. After vertices have undergone model-view and projection transformations, they are transformed into clip space. This space is typically defined as a cube with coordinates ranging from -1 to +1 along each axis (x, y, and z).

The purpose of clipspacekoordinaatti is to simplify the subsequent clipping and viewport transformations. By normalizing the coordinates to this fixed range, it becomes straightforward to determine which parts of the geometry lie within the viewing frustum. Any geometry outside this -1 to +1 cube is considered outside the view and can be discarded, a process known as clipping.

The transformation from clip space to screen space (or window coordinates) involves a perspective divide and a subsequent scaling and translation operation. The perspective divide is crucial because it corrects for the foreshortening effect inherent in perspective projection. After the divide, the coordinates are then mapped to the dimensions of the output viewport, typically in pixel units.

In essence, clipspacekoordinaatti acts as an intermediate representation that bridges the gap between the abstract projection of 3D geometry onto a 2D plane and its final rendering onto a display device. It standardizes the representation of visible geometry, making the clipping and rasterization stages more efficient and manageable.