FMX.TMesh (Delphi)

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Description

This example shows how to use a TMesh object. This example draws two square surfaces that form a corner (the intersection of two adjacent sides of the rectangular 3D shape), by setting the Data property of the TMesh object.

To build and test this example, create a 3D FireMonkey Application - Delphi, then add the next objects to the form:

Add the following code to the OnCreate event handler of the form:

Code

procedure TForm1.Form3DCreate(Sender: TObject);
var
  I: integer;
begin
  //links the texture to the shape.
  Mesh1.MaterialSource:=TextureMaterialSource1;
  //populates the first combo box
  for I := 1 to 4 do
    ComboBox1.Items.Add(IntToStr(I) + ' mesh triangles');
  ComboBox1.ItemIndex := 3;

  //populates the second combo box
  ComboBox2.Items.Add('Texture per side');
  ComboBox2.Items.Add('Stretched');
  ComboBox2.Items.Add('Other');

  ComboBox2.ItemIndex := 0;
  
  //Initialize the points that define the shape and their normals
  Mesh1.Data.Normals :=
    '0.0 0.0 -1 ,0.0 0.0 -1 ,0.0 0.0 -1 ,0.0 0.0 -1 ,0.0 0.0 1 ,0.0 0.0 1 ,0.0 0.0 1 ,0.0 0.0 1';
  Mesh1.Data.Points :=
    '-3 -3 3 ,3 -3 3 ,-3 3 3 ,3 3 3 ,3 -3 3 ,3 -3 -3 ,3 3 3 ,3 3 -3';
end;

Add the following code to the OnChange event handler of each combo box.

Code

procedure TForm1.ComboBox1Change(Sender: TObject);
begin
  case ComboBox1.ItemIndex of
    0: //one triangle is drawn
      Mesh1.Data.TriangleIndices := '0 1 2';
    1: //two triangles are drawn
      Mesh1.Data.TriangleIndices := '0 1 2 ,2 1 3';
    2://three triangles are drawn
      Mesh1.Data.TriangleIndices := '0 1 2 ,2 1 3 ,4 5 6';
    3://four triangles are drawn
      Mesh1.Data.TriangleIndices := '0 1 2 ,2 1 3 ,4 5 6 ,6 5 7';
  end;
end;

procedure TForm1.ComboBox2Change(Sender: TObject);
begin
  case ComboBox2.ItemIndex of
    0://the texture is stretched over each side separately
      Mesh1.Data.TexCoordinates :=
        '0.0 0.0 ,1 0.0 ,0.0 1 ,1 1 ,1 0.0 ,0.0 0.0 ,1 1  ,0.0 1';
    1: //the texture is stretched over both sides. 
      Mesh1.Data.TexCoordinates :=
        '0.0 0.0 ,0.5 0.0 ,0.0 1 ,0.5 1 ,0.5 0.0 ,1 0.0 ,0.5 1 ,1 1';
    2:// the texture is applied with a different pattern 
      Mesh1.Data.TexCoordinates :=
        '0.0 0.0  ,1 1 ,0.0 1  ,1 0.0 ,1 0.0 ,0.0 1 ,1 1 ,0.0 0.0';
  end;
end;

The result should look like in the following images:

TMesh texture each side.PNG TMesh texture stretched .PNG

Uses

See Also

Personal tools
Assistance