msalpha(3G)							   msalpha(3G)

NAME    [Toc]    [Back]

     msalpha - specifies treatment of alpha values during multisample
     rendering

C SPECIFICATION    [Toc]    [Back]

     void msalpha(long mode)

PARAMETERS    [Toc]    [Back]

     mode   is a symbolic constant.  MSA_MASK and MSA_MASK_ONE indicates that
	    alpha values are to	be converted to	multisample mask values	just
	    prior to the alpha test.  MSA_ALPHA	indicates that no such
	    conversion is to be	done.  The default is MSA_ALPHA.

DESCRIPTION    [Toc]    [Back]

     When msalpha is set to MSA_MASK or	MSA_MASK_ONE, while multisampling is
     enabled, source alpha values generated by rasterization are converted to
     multisample masks immediately prior to the	per-pixel alpha	tests.	At
     each pixel	the resulting multisample mask is logically ANDed with the
     mask specified by msmask.	Only multisample locations enabled by the
     resulting mask are	considered for modification.

     When msalpha is set to MSA_MASK_ONE, the source alpha becomes 1.0 after
     the mask has been generated.

     When msalpha is set to MSA_ALPHA, no change is made to the	alpha values
     generated by rasterization	or to the mask specified by msmask.

     msalpha has no effect when	multisample is not enabled.

SEE ALSO    [Toc]    [Back]

     msmask, mspattern,	mssize,	multisample

NOTE    [Toc]    [Back]

     IRIS-4D G,	GT, GTX, VGX, and VGXT models, the Personal Iris, Indigo
     Entry, Indy, XL, XS, XS24,	XZ, Elan and Extreme systems do	not support
     msalpha.


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