OpenGL force discrete or dedicated board use (ISSUE)
lazarus / 70-OpenGL

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LeP · 2026-03-02 18:12

Posted here, even though it's not strictly related to OPENGL.
Needing to set the device used for rendering in OPENGL, I found an old
repo searching the web with broken code to fix this.
I fixed the code (a few things) and tested it in both Delphi and
Lazarus.
In Delphi, it works fine, but in Lazarus, it gives me an internal
compilation error (Lazarus 4.6 / FPC 3.2.2):

QuoteFatal: Internal error 200709272
I haven't found a way to fix it, and I saw that a report on FPC has
been around for years at this link:
https://gitlab.com/freepascal.org/fpc/source/-/work_items/29778

If anyone wants to refresh the report (I don't have an account).

This is the code (the unit name has also been changed in the tests):

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 unit
OPENGL_SETDEVICE; {$mode ObjFPC}{$H+} interface {$ifndef fpc}uses
WinApi.Windows;{$endif}             // Force usage of dedicated GPU
for OpenGL with Delphi and FreePascal/Lazarus on Multi-GPU systems
such as Notebooks on Windows// Insert that into your main source file,
which is for example the .dpr (Delphi) or .lpr (Lazarus) file or use
it like a unit// NOTE: this works only if the screen (NVidia panel) is
set in Auto Mode const   ForceDedicatedGPUUsage = 1;   //set 0 for
integrated GPU (like as for Intel CPU or Amd CPU) and 1 for dedicate
as NVidia implementation{$if defined(Win64) or defined(Win32)}{$ifdef
fpc} {$asmmode intel}{$endif}procedure NvOptimusEnablement; {$ifdef
fpc}assembler; nostackframe;{$endif}asm{$ifdef cpux64}{$ifndef
fpc} .NOFRAME{$endif}{$endif} dd ForceDedicatedGPUUsageend; procedure
AmdPowerXpressRequestHighPerformance; {$ifdef fpc}assembler;
nostackframe;{$endif}asm{$ifdef cpux64}{$ifndef
fpc} .NOFRAME{$endif}{$endif} dd
ForceDedicatedGPUUsageend;{$endif} exports NvOptimusEnablement,      
AmdPowerXpressRequestHighPerformance; end.