GLScene Linux bug?
lazarus / 70-OpenGL

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dicepd · 2017-08-28 08:46

I cannot get a GLSceneViewer to display on a tabbed pagecontrol at
runtime. In design time I can see the scene, switch between tabs and
all looks fine.
However running the app all I get is a blank tabsheet.
The navigator is reporting fps when I try to 'spin' the view, so it
would appear to be rendering somewhere, but not getting drawn to to
screen.
This works fine in Win64.


Linux version Mint 17.2 64bit
fpc 3.0.4rc1
Laz  1.8.0rc4 x64_gtk

Attached is the most basic of test app that shows the bug.

This is what it should look like when run (screenshot from win64)

Peter

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BeanzMaster · 2017-08-28 21:47

Hi Peter, I don't have Linux. I'm really need to install a version.

I take a look in the code, and it seems the possible error provide
from :
1st : It is internal to the LCL and the Tab component (but why ?)
2nd :  the problem can provide from GLWidgetContext.pas in "procedure
TGLWidgetContext.DoGetHandles(outputDevice: HWND; out XWin: HWND);" 
around line 143. The Handle may not be valid.

It's all i can do at this time. Sorry to not be able to do more.

Cheers

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dicepd · 2017-08-30 15:06

Quote2nd :  the problem can provide from GLWidgetContext.pas in
"procedure TGLWidgetContext.DoGetHandles(outputDevice: HWND; out XWin:
HWND);"  around line 143. The Handle may not be valid.

Jerome I had a dig around this area and it would appear that the
GTKWidget does not have a valid window as seen from the variable
evaluation in a debug of this routine. There looks to be a valid input
to the outputdevice parameter.

so the call

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i XWin :=
GDK_WINDOW_XWINDOW(PGdkDrawable(vGTKWidget^.window));  
is always going to return 0 if vGTKWidget^.window has a zero value.

Peter

Code: [Select]<TGTKWIDGET> = {
  ANOBJECT = {
    PARENT_INSTANCE = {
      G_TYPE_INSTANCE = {
        G_CLASS = $1209ef0},
      REF_COUNT = 1,
      QDATA = $120a9e0},
    FLAGS = 2100768},
  PRIVATE_FLAGS = 15744,
  STATE = 0,
  SAVED_STATE = 0,
  NAME = $0,
  STYLE = $1122020,
  REQUISITION = {
    WIDTH = 0,
    HEIGHT = 0},
  ALLOCATION = {
    X = 48,
    Y = 132,
    WIDTH = 302,
    HEIGHT = 176},
  WINDOW = $0,
  PARENT = $11fc490}

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BeanzMaster · 2017-08-31 20:25

Hi, Peter, I've dig too. But not found anything. I don't understand
well GTK2Widgets. And i can't test. The better will be ask in the Unix
forum here. I'll do some deep search.

In Waiting,  perhaps, try  changing vGTKWidget^.window to
vGTKWidget^.parent^.Window

One thing else you can try to add a TPanel on the tab and TGLViewer on
this TPanel to see.

jérôme.

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dicepd · 2017-09-02 09:10

Quote from: BeanzMaster on August 31, 2017, 10:25:16 pmIn Waiting, 
perhaps, try  changing vGTKWidget^.window to
vGTKWidget^.parent^.Window

It would seem that none of the parents have a window attribute which
is not $0.


Quote from: BeanzMaster on August 31, 2017, 10:25:16 pmOne thing else
you can try to add a TPanel on the tab and TGLViewer on this TPanel to
see.

Similar to above except I now have an extra parent with a null for the
window atrribute.

It would seem this is getting called before the GTKWidgets are
properly initialised. I also am not very conversant with GTK window
handling and the gtk model of doing things. None of the parents have
thier positions or sizes set at the point this call is made, pos is
-1,-1 and size is 1,1 for all parent widgets. Pos and size are set
according to the properties set in the ide for the scene viewer
though.

Peter