| 摘要 |
PURPOSE:To reduce remarkably a necessary memory capacity by executing a point transformation from a more distant part than a visual point. CONSTITUTION:A distance between each point and a visual point is derived from the following expression. NRO=NEY-XcosEA*sinEB-YsinEA- ZcosEAcosEB. In this regard, X, Y and Z, NEY, EA, and EB denote points of a perspective transformation, a distance between a visual point and an origin, an angle made by the visual point and an XZ plane, and an angle made by an axis Z and a point projected to the XZ plane, respectively. Subsequently, each point is brought to the perspective transformation by the following expressions. NXP=XcosEB-ZsinEB and NYP=XsinEBsinEA-YcosEA+ ZcosEBcosEA. In this regard, NXP and NYP denote X and Y coordinates on the plane of projection. In this way, this system is operated at the speed being equal to a Z buffer algorithm which is used most at present, and also a necessary memory capacity can be reduced remarkably. |
