mspatt(3G)

NAME
     mspatt - specifies a multisample sample pattern

FORTRAN 77 SPECIFICATION
     subroutine mspattern(pattern)
     integer*4 pattern

PARAMETERS
     pattern   is one of several enumerated values:

              MSPDEF
              MSP2P0
              MSP2P1
              MSP4P0
              MSP4P1
              MSP4P2
              MSP4P3

DESCRIPTION
     By default multisample samples are located in a cluster surrounding each
     pixel center.  The default locations are chosen to produce an optimal
     result in a single rendering pass.  Higher image quality can be achieved,
     however, if multiple multisample images are composed using the
     accumulation buffer.  To do this effectively, a different sample pattern
     must be used for each rendering pass.  mspatt allows these different
     patterns to be specified.

     Patterns MSP2P0 and MSP2P1 are designed to provide optimal results in a
     2-pass rendering.  Patterns MSP4P0 through MSP4P3 provide optimal results
     in a 4-pass rendering.  In both cases, the images resulting from each
     pass should be accumulated with equal weights.

     mspattern should be changed only between complete rendering passes.  It
     should not be changed between the time clear/czclear is called and the
     time that the rendered image is complete.

     mspatt selects the appropriate sample locations as a function of the
     number of samples in the current multisample buffer.  The configuration
     of the multisample buffer should not be changed during the accumulation
     of a single image.

     mspatt is ignored when the multisample buffer is not enabled.

EXAMPLE
     This example configures the framebuffer with both a multisample buffer
     and an accumulation buffer.
          RGBmod();
          double();
          acsize(12);
          mssize(4,32,0);
          gconfi();
          lsetde(getgco(GCMZMA),getgco(GCMZMI));
          zfunct(ZFGEQU);
          zbuffe(TRUE);
          multis(TRUE);

          mspatt(MSP2P0);
          czclea(0,0);
          /* draw the scene */
          acbuf(ACCLRA,1.0);
          mspatt(MSP_2PASS_1);
          czclea(0,0);
          /* draw the scene again */
          acbuf(ACACCU,1.0);
          acbuf(ACRETU,0.5);
          swapbu();

SEE ALSO
     msalph, msmask, mssize, multis

NOTE
     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
     mspatt.