Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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@lang       : en
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View Ref-FileVsetMask()                                                            XBIOS

Syntax

VOID VsetMask( ormask, andmask, overlay )
LONG ormask, andmask;
WORD overlay;

Function      VsetMask() provides access to 'overlay' mode.

Opcode        92 (0x5C)

Availability  Available if the '_VDO' cookie has a value of 0x00030000 or
              greater.

Parameters    When the VDI processes a vs_color() call. It converts the
              desired color into a hardware palette register. In 16-bit
              true-color mode, this is a WORD formatted as follows:

              RRRR RGGG GGXB BBBB

              The 'X' is the system overlay bit. In 24-bit true color
              a LONG is formatted as follows:

              XXXXXXXX RRRRRRRR GGGGGGGG BBBBBBBB

              VsetMask() sets a logical OR and AND mask which are applied
              to this register before being stored. The default system
              value for ormask is 0x00000000 and the default value for
              andmask is 0xFFFFFFFF. overlay should be OVERLAY_ON (1) to
              enable overlay mode or OVERLAY_OFF (0) to disable it.

Binding       move.w  overlay,-(sp)
              move.l  andmask,-(sp)
              move.l  ormask,-(sp)
              move.w  #$92,-(sp)
              trap    #14
              lea     12(sp),sp

Comments      To make colors defined by the VDI transparent in 16-bit true
              color with overlay mode enabled, use an andmask value of
              0xFFFFFFDF and an ormask value of 0x00000000. To make colors
              visible, use an andmask of 0x00000000 and an ormask of
              0x00000020.