Conventionally, such techniques have been proposed, where a plurality of objects are placed in a virtual three-dimensional space, and with elapse of time in the virtual three-dimensional space taken into consideration, these objects are appropriately moved along with the elapse of time to try various simulations and to display, by three-dimensional graphics, the state of these objects as observed from a predetermined viewpoint along a predetermined sight line. Further, such techniques are also proposed, which change the position of the viewpoint and the sight line along which the three-dimensional space is observed along with the elapse of time, and such techniques typically include one that sets a viewpoint on any of the objects and sets the sight line along which the three-dimensional space is observed in a direction in which the set object moves, or one that sets such a sight line by the very sight line of the set object.
In such simulations, it is necessary to consider the collisions between the objects. The literature indicated below discloses a technique which detects a collision between characters in a three-dimensional game, in real time.
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. H11-197357.
Conventionally, in screen display for such a collision, it has been considered necessary to perform processes in real time, by synchronizing the elapse of time in the virtual three-dimensional space and the elapse of time in the real world.
However, particularly, in a case where the shapes of the objects are varied or there are a large number of objects, the calculations become complicated and enormous if the calculations consist in accurately detecting the collision and accurately calculating the movements of the objects at the time of collision, and thus such calculations have been virtually impossible in some cases.
On the other hand, if the collision detection and the object's movements at the time of collision are calculated approximately, a so-called “polygon missing” or an otherwise impossible situation (for example, the viewpoint entering the inside of an object having no hollow, etc.) occurs and the displayed screen might be unnatural.