mspattern(3G)

NAME
     mspattern - specifies a multisample sample pattern

C SPECIFICATION
     void mspattern(long pattern)

PARAMETERS
     pattern   is one of several enumerated values:

              MSP_DEFAULT
              MSP_2PASS_0
              MSP_2PASS_1
              MSP_4PASS_0
              MSP_4PASS_1
              MSP_4PASS_2
              MSP_4PASS_3

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.  mspattern allows these different
     patterns to be specified.

     Patterns MSP_2PASS_0 and MSP_2PASS_1 are designed to provide optimal
     results in a 2-pass rendering.  Patterns MSP_4PASS_0 through MSP_4PASS_3
     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.

     mspattern 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.

     mspattern is ignored when the multisample buffer is not enabled.

EXAMPLE
     This example configures the framebuffer with both a multisample buffer
     and an accumulation buffer.

          RGBmode();
          doublebuffer();
          acsize(12);
          mssize(4,32,0);
          gconfig();
          lsetdepth(getgconfig(GC_MS_ZMAX),getgconfig(GC_MS_ZMIN));
          zfunction(ZF_GEQUAL);
          zbuffer(TRUE);
          multisample(TRUE);

          mspattern(MSP_2PASS_0);
          czclear(0,0);
          /* draw the scene */
          acbuf(AC_CLEAR_ACCUMULATE,1.0);
          mspattern(MSP_2PASS_1);
          czclear(0,0);
          /* draw the scene again */
          acbuf(AC_ACCUMULATE,1.0);
          acbuf(AC_RETURN,0.5);
          swapbuffers();

SEE ALSO
     msalpha, msmask, mssize, multisample

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
     mspattern.