pixelt(3G)

NAME
     pxlxfr -  sets pixel/texel transfer modes

FORTRAN SPECIFICATION
     subroutine pxlxfr(mode, index)
     integer*4 mode
     real index

PARAMETERS
     mode   expects the symbolic name of the pixel transfer parameter being
            set.

     value  expects the value of the pixel transfer parameter being set.

DESCRIPTION
     RealityEngine supports a sequence of of floating point image processing
     operations.  The operations are performed in the following order: integer
     to floating point conversion, scale, bias, convolution, floating point to
     integer conversion, and finally lookup table mapping.

     The pixels are converted from integers in the range specified by
     pixmode(PM_INPUT_TYPE), to the floating point range [0.,1.] if the input
     type was unsigned or (-1.,1] if the input type was signed. The pixels are
     multiplied by a color scale and then a color bias is added.  The scale
     and bias values are specified using the pixeltransfer() function. The
     resulting pixels are convolved, if convolution has been enabled by the
     convolve() function.  The resulting pixels are converted back to integers
     where the range [0.0,1.0] maps to [0,4095] if pixeltransfer(PT_MAP_COLOR)
     is disabled or [0,lookup_table_size), if table lookup mapping is enabled.
     The result is written to the framebuffer.

     The operation of lrectwrite, rectcopy, lrectread, subtexload and
     fbsubtexload can be altered with the pixel transfer command. The
     following modes are recognized

     PT_RED_SCALE specifies that the red, or luminance component of pixels and
     all texel components are scaled by value.

     PT_RED_BIAS specifies that the red, or luminance component of pixels and
     all texel components are biased by value.

     PT_GREEN_SCALE specifies that the green component of pixels are scaled by
     value.

     PT_GREEN_BIAS specifies that the green component of pixels are biased by
     value.

     PT_BLUE_SCALE specifies that the blue component of pixels are scaled by
     value.
     PT_BLUE_BIAS specifies that the blue component of pixels are biased by
     value.

     PT_ALPHA_SCALE specifies that the alpha component of pixels are scaled by
     value.

     PT_ALPHA_BIAS specifies that the alpha component of pixels are biased by
     value.

     PT_MAP_COLOR enables or disables the LUTS (LookUp Tables) defined by
     pixelmap.  The values allowed are PT_MAP_ENABLE, PT_MAP_DISABLE, and
     PT_MAP_CLAMP which may be logically ored with PT_MAP_ENABLE to force
     clamping of values. The need to clamp may slow the LUT operation.
     PT_MAP_COLOR has no effect on lrectread.

SEE ALSO
     convolve, pixelmap

NOTES
     pixeltransfer only works on RealityEngine systems running 5.0.1 or
     greater.  It requires that the pixelzoom factors are both 1.0.