Patent ID: 6906715

Claim:
A method for shading and texturing a 3-dimensional computer generated image for presentation of the image on a display, the display consisting of a plurality of elementary areas, said method including the steps of: supplying data defining a set of surfaces that represent each object in the image; for each elementary area of the display, based on the surface-defining data, generating a depth value for the object surfaces that may be visible at the elementary area as a function of the distances of the object surfaces at the elementary area from an image plane; determining translucency values for texture data to be applied to object surfaces at an elementary area to determine whether or not, at the elementary area, the object surfaces are opaque; for a first opaque object surface at the elementary area, storing the depth value for the surface; for one or more subsequent opaque object surfaces at the elementary area, for each opaque object surface, comparing the depth value of the subsequent opaque object surface to the stored depth value for the opaque object surface at the elementary area and for which the depth value is stored; and between consecutive said steps of comparing depth values, if, in said step of comparing the depth value of the subsequent opaque object surface to the stored depth value it is determined that the subsequent opaque object surface is closer to the image plane than the opaque object surface associated with the stored depth value, replacing the stored depth value with the depth value for the subsequent opaque object surface; wherein only after said step or said steps of comparing the depth value of the subsequent opaque object surface to the stored depth value and replacing the stored depth value with the depth value for the subsequent opaque object surface are executed, at the elementary area, rendering the opaque object surface for which, at the elementary area, the depth value is stored.