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Feb 8, 1999, 8:26am

Hi jeanphi:

A short diggression about querying in Delphi.

Before starting, I install the following:

procedure InstallBuild();
var rc, x, z: Integer;
begin
aw_kallback_set(AW_CALLBACK_QUERY, at cbkQuery);
rc := aw_event_set(AW_EVENT_CELL_BEGIN, at evtCellBegin);
rc := aw_event_set(AW_EVENT_CELL_OBJECT, at evtCellObject);
rc := aw_event_set(AW_EVENT_CELL_END, at evtCellEnd);

rc := aw_event_set(AW_EVENT_OBJECT_ADD, at evtObjectAdd);
rc := aw_event_set(AW_EVENT_OBJECT_DELETE, at evtObjectDelete);

aw_kallback_set(AW_CALLBACK_OBJECT_RESULT, at cbkObjectResult);
end;

Then I calculate the cell (cNS, cWE) and sector (sNS, sWE) coords for
a given position (pNS, pWE) in cm:

procedure SectorFromPosition(pNS, pWE: Integer; var cNS, cWE, sNS,
sWE: Integer);
begin
cNS := Round((pNS-499.5)/1000); {is NOT the central cell of
sector}
cWE := Round((pWE-499.5)/1000);
sNS := aw_sector_from_cell(cNS); {central sector of the zone}
sWE := aw_sector_from_cell(cWE);
end;

Your Sequence[<NS from 0 to 2>, <WE from 0 to 2>] array has the
following meaning:

- each pair "represents" a sector of your 9-sector zone, organised so:
(2,2) NW | (2,1) NC | (2,0) NE
....
(0,2) SW | (0,1) SC | (0,0) SE

the central (2,1) representing your sNS, sWE calculated above. This
array of integers should contain zeros or a valid sequence from a
previous query, and will be updated in the following order: (1,1),
(0,0) etc as in this diagram (thanks Canopus for this tip):

9 8 7
6 1 5
4 3 2

If you use multi-instances, dont forget to set your intstance before
querying.
aw_instance_set(Instance);
rc := aw_query (sWE, sNS, Sector);
where Sector, of type SectorSeqs, is my Sequence array in disguise:
type SectorSeqs = Array[0..2, 0..2] of Integer;

NB: in aw_query you pass in this order: WE, NS, but in the Sequence
array the order is reversed: NS, WE!

If everything went right, this should start off the query, getting
events:

AW_EVENT_CELL_BEGIN, my evtCellBegin
with the following attributes:
aw_instance;
aw_int(AW_CELL_Z);
aw_int(AW_CELL_X);
aw_int(AW_CELL_SIZE);
aw_int(AW_CELL_SEQUENCE);

and a series of
AW_EVENT_CELL_OBJECT, my evtCellObject
with attributes:
aw_instance;
aw_int(AW_OBJECT_NUMBER);
aw_int(AW_OBJECT_OWNER);
aw_int(AW_OBJECT_BUILD_TIMESTAMP);
aw_int(AW_OBJECT_Z);
aw_int(AW_OBJECT_X);
aw_int(AW_OBJECT_Y);
aw_int(AW_OBJECT_YAW);
aw_string(AW_OBJECT_MODEL);
aw_string(AW_OBJECT_DESCRIPTION);
aw_string(AW_OBJECT_ACTION);

followed by a useless event
AW_EVENT_CELL_END

This CellBegin to CellEnd will repeat itself, and then:

if you didnt install the the callback AW_CALLBACK_QUERY then aw_query
will block until all this is done. If you installed the callback, then
this series of events ends inthis callback, my cbkQuery(rc: Integer),
where you can retreive the following attributes:
aw_instance;
aw_bool(AW_QUERY_COMPLETE);

If AW_QUERY_COMPLETE is false, you must call aw_query again to
continue the query (if you wish a complete query). If it is true, then
the query is complete, and live update starts if the event handlers
aw_event_set(AW_EVENT_OBJECT_ADD, at evtObjectAdd);
aw_event_set(AW_EVENT_OBJECT_DELETE, at evtObjectDelete);
are installed.

This is the first part of the story. It's in AW_EVENT_CELL_OBJECT
where you can test whether your required object was found.

XelaG.


--
Xelagot 46ADB [Delph]
creator: XelaG
email: decastro at cable.a2000.nl

Feb 8, 1999, 8:29am

Errata:


the central (2,1) representing your sNS, sWE calculated above. This
array of integers should contain zeros or a valid sequence from a
previous query, and will be updated in the following order: (1,1),
(0,0) etc as in this diagram (thanks Canopus for this tip):

should read:


the central (1,1) .... etc...

--
Xelagot 46ADB [Delph]
creator: XelaG
email: decastro at cable.a2000.nl

Feb 8, 1999, 8:59am

Another clarification. In

AW_EVENT_CELL_BEGIN

cNS := aw_int(AW_CELL_Z)
cWE := aw_int(AW_CELL_X)
qSeq := aw_int(AW_CELL_SEQUENCE)

sxNS := aw_sector_from_cell(cNS);
sxWE := aw_sector_from_cell(cWE);

sapNS := sxNS - sNS + 1;
sapWE := sxWE - sWE + 1;

where sNS, sWE are the central sector coords as calculated above.

Overflow := (sapNS < 0)
or (sapNS > 2)
or (sapWE < 0)
or (sapWE > 2);

Update the Sequence array, if not Overflow:
Sector[sapNS, sapWE] := qSeq;

XelaG.
--
Xelagot 46ADB [Delph]
creator: XelaG
email: decastro at cable.a2000.nl

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