Hi, my Application is a complex Application (An architectural CAD called "Easy Architect 3D", see
here for a screenshot ), it is 8 years old and I never noticed this problem.
It is written in Delphi (Object Pascal), I've tried to isolate some piece of code. here is the first part (it draw the scene in "Selection mode"):
Note: SELECTION_BUFFER_SIZE is a constant: 30000
"Self" in Delphi means "This" in C++
glInitNames; ZeroMemory(@(Self.FSelBuf^),SELECTION_BUFFER_SIZE*sizeof(TGLUInt)); glSelectBuffer(SELECTION_BUFFER_SIZE,@(Self.FSelBuf^)); glRenderMode(GL_SELECT); glClear(GL_DEPTH_BUFFER_BIT); Self.FWorld.DrawFastEx(NIL,FALSE); // Draw the Objects // Back to render mode (see OpenGL Develop Guide) Self.FSelCount:=glRenderMode(GL_RENDER); if Self.FSelCount>0 then begin Self.ProcessHints; Self.FSelCount:=0; end;Here is an extract of the code of the Method "ProcessHints" that analize the response:
k:=0;
for i:=0 to Self.FSelCount-1 do
begin
nItems:=Self.FSelBuf;
inc(k);
zMin:=Self.FSelBuf; // Minimum depth value of primitives (range 0 to 2^32-1)
inc(k);
zMax:=Self.FSelBuf[k
]; // Maximum depth value of primitives (range 0 to 2^32-1)
inc(k);
zValue:=zMin; // I use zValue to detect the neares primitive selected
......
......What I see is that the Items are all detected, but I need to detect the nearest one. So I use "zMin".
Objects are drawn (more or less) in this way:
IList:=Self.FItemsList.FList;
glPushName(GL_ITEM_SELECTED); // This is an Item ...
for i:=0 to IList.Count-1 do
begin
Item:=TGLItem(IList);
glPushName(i);
if not Item.Draw then result:=FALSE;
glPopName;
end;
glPopName;The problem is that zMin and zMax values are completely wrong for all primitives.
Thank you.
Delle
