Strange TGLMeshLines display

[Liang Rong]

Hello

I try to draw city roads. Using TGLLines is result fine (see attachment) but since the speed is slow on zooming/rotation, I switch to TMeshLines. But then I have very strange result by diffeent linewidth (see attachment),

I have following codes for TMeshLines as:

  function CreateNewMeshLineItem(OwnerPlane:TGLPlane; var MeshLine:TMeshLines3D):TLineItem;
  var
    FGLMeshLines: TGLMeshLines;
  begin
    // we will have only one Meshline for one plane to hold all the roads
    // and each road is a one TLineItem
    if  FGLMeshLines=nil then
    begin
      FGLMeshLines :=TMeshLines(CityPlane.AddNewChild(TMeshLines));
     // do not forget EndUpdate at finishing loading roads
     FGLMeshLines.BeginUpdate;
      FGLMeshLines.NoZWrite := True;
      FGLMeshLines.ShowNodes := False; 
      FGLMeshLines.Material.FrontProperties.Emission.Color :=clrGold;
    end;

    // we need a new lineitem for a new road,
    Result :=FGLMeshLines.Lines.Add;
    Result.Name :='Road'+IntToStr(FGLMeshLines.Lines.Count);
    // default
    Result.SplineMode :=lsmLines;
    Result.Division := 1;
    Result.TextureCorrection := False;
    Result.BreakAngle := -1;
    Result.TextureLength := 0.1;
    Result.Width :=1;
    Result.Nodes.Clear;
  end;

Is there any setting I have missed, who will make TMeshlines looked as normal lines?

Thanks.

[Liang Rong]

Here is the attachment for using TGLLine

[Liang Rong]

using Meshlines

[Liang Rong]

TGLMeshLines with a different linewidth

[Pavel Vassiliev]

Hi, Liang
Please, attach your project to look at object properties in your form
and check the code in sample demo
https://sourceforge.net/p/glscene/code/HEAD/tree/branches/Examples/MeshLines/

[Liang Rong]

Hello

Here in attachment is the code to demo. Please select the 'road.mif" file in attachment, who contains the road data in city.

by default, we will use the TMeshline with linewidth 0.1, and after you uncheck the "use TMeshline", TGLLines will be used, and then you can compare the result.

Thanks.

[lnebel]

Hi

I have not been able to compile your code (units missing), but try to offset
the lines from the plane. The effects shown in the image are typical when
objects have the exact same coordinate.

Lars

Fra: Liang Rong [mailto:easyblue@users.sf.net]
Sendt: 7. maj 2016 02:30
Til: [glscene:discussion] 93606@discussion.glscene.p.re.sf.net
Emne: [glscene:discussion] Strange TGLMeshLines display

Hello

Here in attachment is the code to demo. Please select the 'road.mif" file in
attachment, who contains the road data in city.

by default, we will use the TMeshline with linewidth 0.1, and after you
uncheck the "use TMeshline", TGLLines will be used, and then you can compare
the result.

Thanks.

Attachments:

• meshtest.zip
  https://sourceforge.net/p/glscene/discussion/93606/thread/a47f0ac0/da89/att achment/meshtest.zip (2.4 MB; application/zip)

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Strange TGLMeshLines display
https://sourceforge.net/p/glscene/discussion/93606/thread/a47f0ac0/?limit=2 5#da89

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[Liang Rong]

Hi

Sorry I have forgotten to remove the Eurekalog units, which is used to catch exceptions.

So I update the source and upload it again.

This "road.mif" is a high-resoltion mapinfo map of city Shanghai, so at the road crossing, and road turns, the coordinates may be the same, while in a large scale, the coordinates reflect the actual longtitude and latitude of each road segments, which can be see from the display using TGLLine.

[lnebel]

Many units are still missing (AdvTrackBar, MemDS, DBAccess, MyAccess,
MyDacVcl, CodeSiteLogging)

Have you tried what I suggested?

Offset the lines from the plane vertically - or try to turn off the plane

Lars

Fra: Liang Rong [mailto:easyblue@users.sf.net]
Sendt: 9. maj 2016 12:46
Til: [glscene:discussion] 93606@discussion.glscene.p.re.sf.net
Emne: [glscene:discussion] Strange TGLMeshLines display

Hi

Sorry I have forgotten to remove the Eurekalog units, which is used to catch
exceptions.

So I update the source and upload it again.

This "road.mif" is a high-resoltion mapinfo map of city Shanghai, so at the
road crossing, and road turns, the coordinates may be the same, while in a
large scale, the coordinates reflect the actual longtitude and latitude of
each road segments, which can be see from the display using TGLLine.

Attachments:

• meshtest.zip
  https://sourceforge.net/p/glscene/discussion/93606/thread/a47f0ac0/48b0/att achment/meshtest.zip (2.6 MB; application/zip)

---

Strange TGLMeshLines display
https://sourceforge.net/p/glscene/discussion/93606/thread/a47f0ac0/?limit=2 5#48b0

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[Liang Rong]

Hi

Sorry I have forgotten to remove the Eurekalog units, which is used to catch exceptions.

So I update the source and upload it again.

This "road.mif" is a high-resoltion mapinfo map of city Shanghai, so at the road crossing, and road turns, the coordinates may be the same, while in a large scale, the coordinates reflect the actual longtitude and latitude of each road segments, which can be see from the display using TGLLine.

[lnebel]

Hey, please check your demo project before uploading. It cannot compile!

If I make it compile by removing links to the missing units, it seems that
the mif-file is not loaded, and no lines are shown.

And, I am not going to help you any further until you at least try my
suggestions!

Fra: Liang Rong [mailto:easyblue@users.sf.net]
Sendt: 9. maj 2016 13:35
Til: [glscene:discussion] 93606@discussion.glscene.p.re.sf.net
Emne: [glscene:discussion] Strange TGLMeshLines display

Hi

Sorry I have forgotten to remove the Eurekalog units, which is used to catch
exceptions.

So I update the source and upload it again.

This "road.mif" is a high-resoltion mapinfo map of city Shanghai, so at the
road crossing, and road turns, the coordinates may be the same, while in a
large scale, the coordinates reflect the actual longtitude and latitude of
each road segments, which can be see from the display using TGLLine.

Attachments:

• meshtest.zip
  https://sourceforge.net/p/glscene/discussion/93606/thread/a47f0ac0/97ea/att achment/meshtest.zip (2.6 MB; application/zip)

---

Strange TGLMeshLines display
https://sourceforge.net/p/glscene/discussion/93606/thread/a47f0ac0/?limit=2 5#97ea

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https://sourceforge.net/p/glscene/discussion/93606/

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[Liang Rong]

Hello

I am really sorry, that the source code is not clean enough.

Now I checked line by line, and removed all other third-party component and debug utilities.

The mif file is loaded by clicking the button, and then an file open dialog will come out to select this mif file, who should be in the source code folder not in the bin folder.

In case of any other problem, please feel free to contact me.

[Dmitry]

Did you solve the problem?