【转帖】using Linetype Data With Opengl
 

using linetype data with opengl
using linetype data with opengl
hello all,
every polyline has some linetype, that should be applied to that line while displaying it. in odreadex sample project i am reading the linetype data from
void dbdumper::dumplinetypes(oddbdatabase* pdb, int indent)
the data for a specific dwg file looks like this (i have pasted the dumped data).
i am displaying the autocad objects like polylines... hatch... etc... using opengl.
my question is how can i use this data in opengl functions (like gllinestipple ..etc)
pattern name ======= byblock
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= bylayer
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= continuous
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= verdeckt
precord->patternlength= 9.525000
precord->numdashes= 2
precord->dashlengthat(0)= 6.350000
precord->dashlengthat(1)= -3.175000
pattern name ======= strichpunkt
precord->patternlength= 25.400000
precord->numdashes= 4
precord->dashlengthat(0)= 12.700000
precord->dashlengthat(1)= -6.350000
precord->dashlengthat(2)= 0.000000
precord->dashlengthat(3)= -6.350000
pattern name ======= acad_iso03w100
precord->patternlength= 30.000000
precord->numdashes= 2
precord->dashlengthat(0)= 12.000000
precord->dashlengthat(1)= -18.000000
pattern name ======= 1192
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= 1183
precord->patternlength= 3.000000
precord->numdashes= 2
precord->dashlengthat(0)= 2.000000
precord->dashlengthat(1)= -1.000000
pattern name ======= 1175
precord->patternlength= 3.000000
precord->numdashes= 2
precord->dashlengthat(0)= 2.000000
precord->dashlengthat(1)= -1.000000
pattern name ======= 1182
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= 1166
precord->patternlength= 3.000000
precord->numdashes= 2
precord->dashlengthat(0)= 2.000000
precord->dashlengthat(1)= -1.000000
pattern name ======= 1165
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= 1058
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= 8058
precord->patternlength= 0.000000
precord->numdashes= 0
pattern name ======= 2
precord->patternlength= 2.000000
precord->numdashes= 2
precord->dashlengthat(0)= 1.000000
precord->dashlengthat(1)= -1.000000
pattern name ======= verdeckt2
precord->patternlength= 4.762500
precord->numdashes= 2
precord->dashlengthat(0)= 3.175000
precord->dashlengthat(1)= -1.587500
pattern name ======= hidden
precord->patternlength= 9.525000
precord->numdashes= 2
precord->dashlengthat(0)= 6.350000
precord->dashlengthat(1)= -3.175000
pattern name ======= hidden2
precord->patternlength= 4.762500
precord->numdashes= 2
precord->dashlengthat(0)= 3.175000
precord->dashlengthat(1)= -1.587500
pattern name ======= dashdot
precord->patternlength= 25.400000
precord->numdashes= 4
precord->dashlengthat(0)= 12.700000
precord->dashlengthat(1)= -6.350000
precord->dashlengthat(2)= 0.000000
precord->dashlengthat(3)= -6.350000
pattern name ======= punkt
precord->patternlength= 6.350000
precord->numdashes= 2
precord->dashlengthat(0)= 0.000000
precord->dashlengthat(1)= -6.350000
pattern name ======= hidden4
precord->patternlength= 2.381200
precord->numdashes= 2
precord->dashlengthat(0)= 1.587500
precord->dashlengthat(1)= -0.793700

hi,
quote:
my question is how can i use this data in opengl functions (like gllinestipple ..etc)
i answer on this question in one of your previous posts sometime ago:
quote:
linetype can contain not only dots and dashes, but also shapes and text. of course, you can manually convert this array to needed form, but this convertion guarantees data lost on many linetypes.
i think impossible to convert dd linetypes representation to opengl binary form. lengths of dashes cannot be correctly converted to 16bit mask and glint multiplication factor for gllinestipple() call. i think only simplest linetypes (dots, dash-dot and etc.) with integer values can be converted, but some of them will be inaccurate.