| 摘要 |
A method and apparatus for simulating the effect of non- homogeneous fog in an image displayed on a screen. The image is intended to represent the appearance of a model defined in a database in world space coordinate; from an eyepoint position in world space, the model being defined in terms of individual features each having predetermined attributes defining the position and visible characteristics of the feature. Image data is derived from the model for each of an array of sampling points distributed across screen space. A non-homogeneous fog structure is defined world space coordinates as a series of parallel strata of predetermined extinction coefficient. The positions of the eyepoint and a feature to be displayed relative to the fog structure are determined. The distance from the feature to the eyepoint is calculated. An average value of the extinction coefficient between the eyepoint and the feature is calculated from the defined parallel strata, and the attributes are modulated as a function of the calculated distance and the calculated average value of the extinction coefficient. |
