摘要 |
<p>Three dimensional computer graphic images are shaded by first supplying data which defines the objects to be inserted into the image, this data including depth data relating to the objects. A depth store (4) includes data for objects already inserted into the image and a depth comparison unit (6) compares the depth of an object to be inserted with the currently stored depth data for a particular pixel. The result of this is used to determine which of a number of depth operations is used to be applied to the depth store (4). A blending value is selected for each pixel for combining the object with the image in dependence on the selected depth operation. A combining unit then combines the object with the image in proportions dependent upon the selecting blending value.</p> |