Masking

A mask is a special image that is used to “mask” off portions of another image. A mask works like a stencil. Since an image is square or rectangular, the mask allows the edges to be any shape, as the game will render the masked portions invisible (see Figures 3.41, 3.42, and 3.43).

Figure 3.41 An image of a ghost.

Figure 3.42 The mask for the ghost image.

Figure 3.43 The mask and image combined in a scene.