Type
TVertex=record
X,Y : Integer;
end;

TBlock=class
 TerrainV : array of array of TVertex;
[...]
end;

  TVertex = packed record
    X,Z : Single;
  end;

  TTerrainBlock=class
    TerrainV : array[0..(64*64)] of TVertex;
    VBO : gluint;
[...]

constructor TTerrainBlock.Create();
var x,y,z : Integer;
begin
z := 0;
   for x := 0 to 63 do
    for y := 0 to 63 do begin

      TerrainV[z].X := X;
      TerrainV[z].Z := Y;
      inc(z);
    end;

  glGenBuffers(1, @VBO);
  glBindBufferARB(GL_ARRAY_BUFFER, VBO);
  glEnableClientState(GL_VERTEX_ARRAY);
  glBufferDataARB(GL_ARRAY_BUFFER, 64*64*SizeOf(TVertex), @TerrainV, GL_STATIC_DRAW);
end;

procedure TTerrain.RenderTerrain;
begin
      //If Frustum.IsBoxWithin(X*64,0,Y*64,64,255,64) then begin
        glInterleavedArrays(GL_V2F, SizeOf(TVertex), nil);
        glDrawArrays(GL_Triangles, 0, 64*64*SizeOf(TVertex));
      //end;
end;

  TVertex = packed record
    X,Z : Single;
  end;

  TTriangle = packed record
    ver : array[0..2] of TVertex;
  end;

  TTerrainBlock=class
    TerrainV : array[0..8192] of TTriangle;
    VBO : gluint;
[...]

constructor TTerrainBlock.Create();
var x,y,z : Integer;
begin
z := 0;
   for x := 0 to 63 do
    for y := 0 to 63 do begin

      TerrainV[z].ver[0].X := X;
      TerrainV[z].ver[1].X := X+1;
      TerrainV[z].ver[2].X := X;
      TerrainV[z].ver[0].Z := Y;
      TerrainV[z].ver[1].Z := Y;
      TerrainV[z].ver[2].Z := Y+1;
      inc(z);

      TerrainV[z].ver[0].X := X;
      TerrainV[z].ver[1].X := X+1;
      TerrainV[z].ver[2].X := X+1;
      TerrainV[z].ver[0].Z := Y+1;
      TerrainV[z].ver[1].Z := Y;
      TerrainV[z].ver[2].Z := Y+1;
      inc(z)
    end;

  glGenBuffers(1, @VBO);
  glBindBufferARB(GL_ARRAY_BUFFER, VBO);
  glEnableClientState(GL_VERTEX_ARRAY);
  glBufferDataARB(GL_ARRAY_BUFFER, 8192*SizeOf(TTriangle), @TerrainV, GL_STATIC_DRAW);
end;