To understand this, we must first take a brief look at the characteristics of the viewing frustum. 要理解这点,我们首先必须简要了解一下试图锥截体的特征。
Since we have split the frustum into two halves, each triangle has an angle at the origin of view equal to FOV/2. 因为将锥截体分成相等两部分,每个三角形在原视图中都有一个角等于FOV/。
Screen coordinates are expressed in number of pixels, while coordinates in the frustum are normalized to a range of-1.0 to1.0. 视图锥截体的原点(,0)屏幕中心,而屏幕坐标的则在屏幕的左上角。
frustum frusta
[ noun ] a truncated cone or pyramid; the part that is left when a cone or pyramid is cut by a plane parallel to the base and the apical part is removed <noun.shape>
Frustum \Frus"tum\, n.; pl. L. {Frusta}, E. {Frustums}. [L. fruslum piece, bit.] 1. (Geom.) The part of a solid next the base, formed by cutting off the, top; or the part of any solid, as of a cone, pyramid, etc., between two planes, which may be either parallel or inclined to each other.
2. (Arch.) One of the drums of the shaft of a column.