Silicon Graphics IRIS Workstation, Руководство пользователя

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Version 1.0
IRIS WORKSTATION GUIDE 157 Appendix L:
hold all the hit data.
For example, suppose that the following sequence of events occurs:
pick(100);
pushname(10);
<hit>;
pushname(20);
<hit>;
<hit>;
popname();
pushname(30);
pushname(65);
<hit>;
popname();
popname();
popname() ;
endpick(foo);
Each <hit> above stands for a graphics library command that would have
caused something to be drawn on the screen. Other drawing commands that
would cause no hits could be arbitrarily interspersed among the commands
above with no effect on the final contents of the array
foo[]
.
In the example above,
endpick()
would return 4: (the number of hits). 4 is
positive, so all hits that occurred are recorded in the buffer. If the result of
endpick()
were negative, some unknown amount of information would be
missing. If there is missing data, then the recorded hits are the first ones that
occurred after
pick()
/
select()
was called.
After
endpick()
, the array
foo[]
contains 12 16-bit numbers:
1 10 -- first hit; one name; stack = [10]
2 10 20 -- second hit; two names; stack = [10 20]
2 10 20 -- third hit; two names; stack = [10 20]
3 10 30 65 -- fourth hit; three names; stack = [10 30 65]
L.4 Programming the IRIS
This section is primarily of interest those wishing to program the IRIS terminal.
The
callfunc()
command is, however, available on both the workstation and
the terminal.
The easiest way to program the terminal is to write a routine in C, add it to a
dispatch table (see the document on programming the IRIS terminal), and then
make the program and remote host stubs. Such a routine will be part of the
terminal program, but cannot be compiled into a display list.
callfunc(procname, nargs, arg1, arg2, ..., argn)
lets you call an arbitrary
routine from within a display list. procname is the name of the procedure to be
called; nargs is the number of arguments; and the arguments are arg1, ..., argn . If
procname
returns a value, it is ignored. All arguments are called by value.