| 摘要 |
A view port comprising an oblique slice intersecting a stack of textured images is defined. A polygon associated with the view port slice is divided into multiple polygons, wherein each polygon is clipped to the surface of each intersecting texture. Each intersecting texture is then enabled, one at a time. When each texture is enabled, each polygon intersecting with the enabled texture is drawn. The colors of the vertices that fall within the active textures are maintained according to the color of the active texture, and the colors of the vertices that fall within the inactive texture are set to zero. This process is repeated until all of the intersecting textures have been enabled. This causes each polygon to be drawn exactly twice. Additive blending is enabled so that the first and second polygons are blended together. When each polygon is drawn, bi-linear interpolation techniques are used to fill-in the colors of the texels that lie in between the vertices of the polygon. The second time the polygon is drawn, the opposite texture used to draw the first polygon becomes the active texture. The first and second polygons are then blended together, resulting in a properly filtered averaged three dimensional image that is rendered using only bi-linear interpolation techniques.
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