A three-dimensional API for communicating with hardware implementations of
vertex shaders and pixel shaders having local registers. With respect to
vertex shaders, API communications are provided that may make use of an
on-chip register index and API communications are also provided for a
specialized function, implemented on-chip at a register level, that
outputs the fractional portion(s) of input(s). With respect to pixel
shaders, API communications are provided for a specialized function,
implemented on-chip at a register level, that performs a linear
interpolation function and API communications are provided for specialized
modifiers, also implemented on-chip at a register level, that perform
modification functions including negating, complementing, remapping, stick
biasing, scaling and saturating. Advantageously, these API communications
expose these very useful on-chip graphical algorithmic elements to a
developer while hiding the details of the operation of the vertex shader
and pixel shader chips from the developer.
