A transformation that preserves straight lines and the ratio of distances of points lying on lines.
Artifacts created by undersampling a scene, typically caused by assigning one point sample per pixel, where there are edges or patterns in the scene of higher frequency than the pixels. This results in jagged edges (jaggies), moiré patterns, and scintillation. See antialiasing.
The fourth color component. The alpha component is never displayed directly, and is typically used to control blending of colors. By convention, OpenGL alpha corresponds to the notion of opacity, rather than transparency, meaning that an alpha value of 1.0 implies complete opacity, and an alpha value of 0.0 complete transparency. ...