METHOD OF CALCULATING ILLUMINANCE IN COMPUTER GRAPHICS

摘要

PROBLEM TO BE SOLVED: To calculate the illuminance of an optional object point with high accuracy while reducing the burden of calculation. SOLUTION: An object T consisting of a set of surfaces S1-Sn which emit energy is defined and the illuminance of energy radiated from the object T is calculated at an optional object point. Reference points R1-Rm are preparatorilly defined around the object T and the energy illuminance values E1-En emitted from the surfaces S1-Sn are calculated as a list for each of points R1-Rm. When the illuminance of the optional object point is calculated, the list is used for a reference point in the vicinity of the optional object point to select K (D<n) pieces of illuminance value in total out of (n) pieces of values E1-En with higher probability as the illuminance value increases. Then K pieces of surfaces corresponding to the selected K pieces of illuminance value are selected out of the surfaces S1-Sn as the sample surfaces, and the illuminance is calculated by taking only the energy that is radiated from the surfaces S1-Sn into consideration.