| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a game system and an information storage medium which can represent a shading process based upon light from a display body indefinitely changing in shape with a small process load. SOLUTION: A representative position (representative direction) RP is computed from the positions of respective virtual light source primitives LS, a representative light source RL is set at the RP, and the shading of an object and the generation of a shadow SD are performed according to the RL. The intensity of the representative light source is computed from the intensity values of lights of the respective virtual light source primitives. As the virtual light source primitives, particles are used which appear, move, and disappear in sequence with the time. The generation quantity, generation positions, movement states, or life of the virtual light source primitives is changed at random. The representative light source of a virtual light source object may be set in the center of gravity of the virtual light source object which has certain volume and changes in shape with the time.</p> |
