| Re: IDLgrPolygon Leak? [message #69991] |
Wed, 03 March 2010 20:00 |
KRDean
Messages: 69
Registered: July 2006
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Member |
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On Mar 3, 5:10 pm, Karl <karl.w.schu...@gmail.com> wrote:
> On Mar 3, 1:24 pm, kBob <krd...@gmail.com> wrote:
>
>
>
>
>
>> Not a memory leak, but a polygon leak.
>
>> The 2010 IDL User Group meeting got me inspired to work with some
>> object graphics mapping.
>
>> However, I am running into some problems with adding a Shapefile to a
>> object graphics window. When I call the IDLgrPOLYGON to draw and fill
>> the shapefile vertices, there seems to be a leak or overflowing the
>> polygon.
>
>> Any thoughts on why. Sample code below. The IDLgrPOLYGON is set to
>> work with vertices that only have one part. Anything else, the
>> IDLgrPOLYLINE is used.
>
>> Kelly Dean
>> Fort Collins, CO
>
>> =============== Test_PolyShp ===============
>
>> ;+
>> ;
>> ; <P>Prepare Shapefile Entities for object model.
>> ;
>> ;----------------------------------------------------------- -----------
>> PRO CountryModel, oModelSHP
>
>> COMPILE_OPT DEFINT32, STRICTARR
>
>> shpFile = FILEPATH( Subdirectory=['resource', 'maps', 'shape'],
>> 'cntry02.shp' )
>> oSHP = OBJ_NEW( 'IDLffShape', shpFile )
>> IF ( OBJ_VALID( oSHP ) ) THEN BEGIN
>> oModelSHP = OBJ_NEW( 'IDLgrModel' )
>> oSHP -> GetProperty, N_ENTITIES = num_ent
>> FOR entn = 0, num_ent-1 DO BEGIN
>> ent = oSHP -> GetEntity( entn )
>> IF ( ent.n_parts GE 2 ) THEN BEGIN
>> cuts = [ (*ent.parts), ent.n_vertices ]
>> FOR partn = 0, ent.N_parts-1 DO BEGIN
>> ; oGon = OBJ_NEW('IDLgrPolygon', (*ent.vertices)[*,
>> cuts[partn]:cuts[partn+1]-1] )
>> oGon = OBJ_NEW('IDLgrPolyline', (*ent.vertices)[*,
>> cuts[partn]:cuts[partn+1]-1] )
>> oGon -> SetProperty, COLOR = [ 034, 139, 87 ] ; Forest Green
>> oModelSHP -> ADD, oGon
>> ENDFOR
>> ENDIF ELSE IF ( ent.n_parts EQ 1 ) THEN BEGIN
>> oGon = OBJ_NEW('IDLgrPolygon', (*ent.vertices) )
>> oModelSHP -> ADD, oGon
>> ENDIF ELSE BEGIN
>> ENDELSE
>> oSHP -> DestroyEntity, ent
>> ENDFOR
>> OBJ_DESTROY, oSHP
>> ENDIF ELSE BEGIN
>> ENDELSE
>
>> END
>> ;+
>> ;
>> ;
>> ;----------------------------------------------------------- -----------
>> PRO Test_PolyShp
>
>> COMPILE_OPT DEFINT32, STRICTARR
>
>> CountryModel, oModelCntry
>> XOBJVIEW, oModelCntry
>
>> ;WARNING: Big time memory leak
>> ;Do IDL> HEAP_GC, /Verbose
>
>> END
>
> IDLgrPolygons need to be convex in order to render properly. (This is
> the case for the underlying OpenGL as well)
>
> I'm guessing that is what you mean by "leak". Drawing non-convex
> polygons with grPolygon can sort of look like a leak.
>
> It does not look like your code takes any steps to ensure that the
> polygons are convex. It may be the case that your database consists
> of only convex shapes, but I don't know that.
>
> To solve this, look at IDLgrTesselator. It will take an arbitrary
> input polygon and emit a covering set of triangles that can then be
> stored in IDLgrPolygon.- Hide quoted text -
>
> - Show quoted text -
Thanks Karl,
This is what I was looking for. Apparently, there are "holes" in the
vertices and it appears IDLgrTesselator will help close them up.
Kelly Dean
Fort Collins, CO
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| Re: IDLgrPolygon Leak? [message #69994 is a reply to message #69991] |
Wed, 03 March 2010 16:10  |
Karl[1]
Messages: 79
Registered: October 2005
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Member |
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On Mar 3, 1:24 pm, kBob <krd...@gmail.com> wrote:
> Not a memory leak, but a polygon leak.
>
> The 2010 IDL User Group meeting got me inspired to work with some
> object graphics mapping.
>
> However, I am running into some problems with adding a Shapefile to a
> object graphics window. When I call the IDLgrPOLYGON to draw and fill
> the shapefile vertices, there seems to be a leak or overflowing the
> polygon.
>
> Any thoughts on why. Sample code below. The IDLgrPOLYGON is set to
> work with vertices that only have one part. Anything else, the
> IDLgrPOLYLINE is used.
>
> Kelly Dean
> Fort Collins, CO
>
> =============== Test_PolyShp ===============
>
> ;+
> ;
> ; <P>Prepare Shapefile Entities for object model.
> ;
> ;----------------------------------------------------------- -----------
> PRO CountryModel, oModelSHP
>
> COMPILE_OPT DEFINT32, STRICTARR
>
> shpFile = FILEPATH( Subdirectory=['resource', 'maps', 'shape'],
> 'cntry02.shp' )
> oSHP = OBJ_NEW( 'IDLffShape', shpFile )
> IF ( OBJ_VALID( oSHP ) ) THEN BEGIN
> oModelSHP = OBJ_NEW( 'IDLgrModel' )
> oSHP -> GetProperty, N_ENTITIES = num_ent
> FOR entn = 0, num_ent-1 DO BEGIN
> ent = oSHP -> GetEntity( entn )
> IF ( ent.n_parts GE 2 ) THEN BEGIN
> cuts = [ (*ent.parts), ent.n_vertices ]
> FOR partn = 0, ent.N_parts-1 DO BEGIN
> ; oGon = OBJ_NEW('IDLgrPolygon', (*ent.vertices)[*,
> cuts[partn]:cuts[partn+1]-1] )
> oGon = OBJ_NEW('IDLgrPolyline', (*ent.vertices)[*,
> cuts[partn]:cuts[partn+1]-1] )
> oGon -> SetProperty, COLOR = [ 034, 139, 87 ] ; Forest Green
> oModelSHP -> ADD, oGon
> ENDFOR
> ENDIF ELSE IF ( ent.n_parts EQ 1 ) THEN BEGIN
> oGon = OBJ_NEW('IDLgrPolygon', (*ent.vertices) )
> oModelSHP -> ADD, oGon
> ENDIF ELSE BEGIN
> ENDELSE
> oSHP -> DestroyEntity, ent
> ENDFOR
> OBJ_DESTROY, oSHP
> ENDIF ELSE BEGIN
> ENDELSE
>
> END
> ;+
> ;
> ;
> ;----------------------------------------------------------- -----------
> PRO Test_PolyShp
>
> COMPILE_OPT DEFINT32, STRICTARR
>
> CountryModel, oModelCntry
> XOBJVIEW, oModelCntry
>
> ;WARNING: Big time memory leak
> ;Do IDL> HEAP_GC, /Verbose
>
> END
IDLgrPolygons need to be convex in order to render properly. (This is
the case for the underlying OpenGL as well)
I'm guessing that is what you mean by "leak". Drawing non-convex
polygons with grPolygon can sort of look like a leak.
It does not look like your code takes any steps to ensure that the
polygons are convex. It may be the case that your database consists
of only convex shapes, but I don't know that.
To solve this, look at IDLgrTesselator. It will take an arbitrary
input polygon and emit a covering set of triangles that can then be
stored in IDLgrPolygon.
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| Re: IDLgrPolygon Leak? [message #69995 is a reply to message #69994] |
Wed, 03 March 2010 15:56 |
David Fanning
Messages: 11724
Registered: August 2001
|
Senior Member |
|
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kBob writes:
>
> Not a memory leak, but a polygon leak.
>
> The 2010 IDL User Group meeting got me inspired to work with some
> object graphics mapping.
>
> However, I am running into some problems with adding a Shapefile to a
> object graphics window. When I call the IDLgrPOLYGON to draw and fill
> the shapefile vertices, there seems to be a leak or overflowing the
> polygon.
>
> Any thoughts on why. Sample code below. The IDLgrPOLYGON is set to
> work with vertices that only have one part. Anything else, the
> IDLgrPOLYLINE is used.
Kelly, you probably already figured this out,
but XObjView doesn't destroy the object that is handed
to it. You have to do that yourself. All this memory
leaking is just due to the model object you created.
For example, you can change your main routine like this.
PRO Test_PolyShp
COMPILE_OPT DEFINT32, STRICTARR
CountryModel, oModelCntry
XOBJVIEW, oModelCntry, /BLOCK
Obj_Destroy, oModelCntry
;WARNING: Big time memory leak
;Do IDL> HEAP_GC, /Verbose
END
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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