METHOD FOR REAL TIME RENDERING OF VARIATION OF DAY AND NIGHT ON GRAPHIC PROCESSED EARTH FLOOR PLAN AND GRAPHIC PROCESSING APPARATUS USING THEREOF

摘要

Disclosed is a method for visualizing night and day change in real time on a plan view of a ground using a pixel shader and a graphics processing device therefor. The present invention relates to a method for real-time visualization of night and day changes in an earth plan view image rendered by a computer graphics processing apparatus, comprising the steps of: (a) converting an earth''s latitude and longitude into RGB values; (b) calculating the slope of the earth''s rotation axis according to the current time; (c) computing a position vector for a point on the surface of the earth at the center of the earth based on the RGB value and the slope of the earth''s rotation axis; (d) determining a sign of an inner product of the position vector and the unit vector of the sun direction at the center of the earth; And (e) if the sign of the inner product value is negative, adding a shading effect to the one point.