| 摘要 |
A bounding volume (20) represents the volume of a scene to be rendered and a graphics texture represents the transparency of the surface of the bounding volume. For a sampling point (25) within or on the boundary volume, a transparency parameter is determined indicating the amount of shadow cast on the point by a light source (22) that is external to the bounding volume. Firstly, a position (26) on the bounding volume intersected by a vector (28) from the sampling point to the light source is determined and is used to sample the graphics texture. Sampling may constitute determining a vector (27) to a reference position that the texture is defined with respect to from the intersection position. The transparency of the surface of the bounding volume between the sampling point and the light source is thereby determined. The so-determined transparency is then used to simulate the effect of shadows cast by the light source at the sampling point. |
