When covering the object surface with a texture the operation to be performed between texture and object surface can be specified. Several operations and textures can be set. The active operation stage to be set is specified by the stage element. The stage number can be 0 through 7. By reading the stage element the maximum number of stages supported by the driver can be identified. The OpenGL and DirectX 3 and 5 drivers support 1 operation stage only: either the modulate operation or the non-modulated color/texture selection. The stage number in other drivers depends on the videocard possibilities, for many videocards being only 2 operation stages available.
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