I am programming a simple OpenGL 3D application. If I am running the application on a laptop, the performance is terrible since the internal Intel GPU is selected always and not the more powerfull dedicated AMD GPU.
I did read that I have to inlclude this line to force the application to run on the dedicated GPU:
extern "C" __declspec(dllexport) DWORD AmdPowerXpressRequestHighPerformance = 0x00000001;
However, I get an LNK2005 error that AmdPowerXpressRequestHighPerformanceis already defined in multiple .obj files. I don't know how to fix this and I didn't find this variable name in any of the files that I did include in my application.
If it helps: I am using GLFW3 and GLAD for the OpenGL rendering.
Make sure you aren't building GLFW with GLFW_USE_HYBRID_HPG defined, which causes GLFW to export NvOptimusEnablement & AmdPowerXpressRequestHighPerformance itself.
Solved by putting the code in the correct place, as suggested in the comments above.
Related
As a Xcode developer I have to use my written code on windows, too. I think I have successful master all cross platform issues but now I have a real problem understanding the DLL hell on Windows.
I used my code with Xcode and Gcc (Ubuntu) successful. On Windows I get a error message:
Run-Time Check Failure #0 - The value of ESP was not properly saved across a function call. This is usually a result of calling a function declared with one calling convention with a function pointer declared with a different calling convention.
I read much about this uses but I have my problems to understand the issue.
Normally on windows I have something like
#define MYLIB_API __declspec(dllimport)
I cannot find this inside the header of the Bass Library (bass.h). There is only one line
#define BASSDEF(f) WINAPI f
Now, I try to dynamic load the DLL functions in my code. You can see the dynamic loading header as link on bottom. To much to copy here. This dynamic loading is working for .dylib and .so libs well, not for .dll
My target is to load the DLL dynamic and not static with an additional lib.
In my code I use the bass.h and the bassdecode.h. In my code I call as sample:
bool returnVar = _BASS_SetConfig(BASS_CONFIG_DEV_DEFAULT,1);
And here I get the calling convention message.
What I have to do in my header file to successful import DLL functions on Windows?
You can download the files at: header files to download
Ok, for all who run into the same problem, the solution is the Answer from Hans Passant. I cannot mark this answer as solution so I want to give him the reputation.
My original typedef of the function:
typedef BOOL (*BASS_SetConfig_Type)(DWORD option, DWORD value);
Was searched in DLL
_BASS_SetConfig = (BASS_SetConfig_Type)DllFindSym(m_hMod, "BASS_SetConfig")
Where DLLFindSym is defined as:
#define DllFindSym(handle,name) (GetProcAddress(handle,name))
Now changed the typedef to
typedef BOOL (__stdcall *BASS_SetConfig_Type)(DWORD option, DWORD value);
Now everything works like a charm in Windows. Many thanks to the quick hint from Hans Passant.
I'm trying to compile a code with this call in Qt5 under Linux and I'm getting this error on compile time.
Any problem of compatibility? Any other error
I have this include:
#include <GL/gl.h>
Try this:
#ifdef Q_OS_WIN
#include "gl/GLU.h"
#else
#include <glu.h>
#endif
When building this example on OSX and on Windows that code worked for me for finding the correct headers.
https://github.com/peteristhegreat/circles-in-a-cube/blob/master/glwidget.cpp
Hope that helps.
glGenFramebuffers() is never declared in the standard GL headers, because that is a function which is not guaranteed to be even exported by the GL library on most platforms. For anything beoynd GL 1.1, the GL extension mechanism has to be used to retrieve the function pointers at run time. There are a couple of different OpenGL loading libraries which do all of this for you under the hood, and also provide appropriate header files so that any GL function can be used as if you were directly linking them.
You already use Qt, which provides its own GL loading mechanism, namely QOpenGLFunctions and the more modern QAbstractOpenGLFunctions class.This article provides a brief overview about the different possibilites.
Also note that Qt provides also the QGLFramebufferObject class as a wrapper around GL's FBOs.
I grepped inside GLEW while trying to solve my other question, concerning missing __glewX* symbols for Mac, and found that they are guarded by GLEW_APPLE_GLX.
When I attempt to build GLEW from source with that flag defined, I get undefined symbols (stuff like _glXGetClientString). Linking against X11 (-lX11) doesn't help.
Question: assuming defining GLEW_APPLE_GLX does indeed make sense, how can I fix the build?
When building an application that uses the X Server (XQuartz) instead of using CGL, you also need to add -lGL.
Ordinarily when building GL software on OS X you use OpenGL.framework (-framework OpenGL) and that gets you OpenGL and CGL/AGL functions but leaves out GLX.
You should also ditch any includes to things like <OpenGL/gl.h> and use <GL/gl.h> instead, as that will point to /usr/X11R6/include/GL/... instead of the OpenGL framework headers.
General info [optional]:
I have recently acquantied with static & dynamic libraries.
Now I am trying to learn how to use DLLs, I try to immitate all possible variants of usage in order to encounter possible bottlenecks and methods to prevent them.
My goal:
Is to find out how to export a global variable from a DLL which was compiled with one compiler for ex. VS compiler (IDE Visual studio 2010) to the client which was compiled using another compiler MingW(IDE Qt Creator 5.0). Actually I am interested in specific case, not common, but if info for common case will be provided - it will be great.
Also important that connection of the dll to the client is implicit(not expilcit then we manually connect library).
Also I have posed such question because it is interesting for me how to support a client`s application by providing updated dll, because version of compiler used for client and dll at the beggining of a project can be the same, but as time passes by they may vary, so how to solve this binary compatibility issue?
I got stuck trying to export an array defined in dll to the client.
DLL & Client
/* header file. Is used by both: dll and client */
#ifdef EXPORT
#define MYLIB __declspec(dllexport)
#else
#define MYLIB __declspec(dllimport)
#endif
extern "C" { // My be this directive not supported by MingW???
#ifdef VS2010
extern MYLIB char ImplicitDLLName[];
#else
Q_DECL_IMPORT extern char ImplicitDLLName[];
#endif
}
DLL
/* .cpp file in dll: */
#define EXPORT ""
#define VS2010 ""
char ImplicitDLLName[] = "MySUMoperator";
Client
/* Client .cpp */
void MainWindow::on_pushButtonAdd_clicked()
{
// ...
printf("%s",ImplicitDLLName);
}
Attempt to use the array in the Client results in the following error raised by the linker:
error: undefined reference to `_imp__ImplicitDLLName'
I am aware of names mangling and compatibilty issue that may arise from that, but I am trying to resolve it by disabeling it using
extern "C"{}
By the error returned from the clients linker I can tell that I have failed to disable it, because it reports that reference on _imp__ImplicitDLLName wasnt found, so I guess that it is ImplicitDLLName only decorated with additional symobls(name mangling).
I wonder may be this issue arose due to different implementation of arrays in different compilers or alignment of arrays in memory??
Question: how to solve this binary comptability issue??
I was about to rebuild my library in Dev-C++, under Windows; however, the shader functionality I've added in the meantime is not supported, the compiler could not find the related functions (::glCreateShader(), ::glCreateProgram(), etc.)
Digging around the internet and the Dev-C++ folder, I've found that the OpenGL implementation (gl.h) is only v1.1. I've found recommendations to download the latest headers from SGI. I have found gl3.h, however, after closer scrutiny I have realized that gl.h is not included in my project anyway, and I should be looking at SDL/SDL_opengl.h.
EDIT: SDL_opengl.h does include gl.h and declares prototypes of the functions in question. So the question is, why ame I given compile-time errors rather than linker errors?
(My library only links against mingw32, libOpenGL32, libSDL, libSDL_Image and libSDL_Mixer, much like under OSX (except for mingw32, of course) where I didn't have any problem.)
How can I use OpenGL v2.0 shaders with Dev-C++ and SDL?
gl.h is only for OpenGL 1.1 (and in some cases up to 1.3 depending on which version of the file you are using and which operating system). For everything else you additionally need glext.h and probably glxext.h (Linux/Unix) or wglext.h (Windows).
All functions from newer versions of OpenGL must be linked at runtime. So in order to use them you must get the right function address and assign it to a function pointer. The easiest way to do this is by using something like GLEW.
The manual way would be something like this:
PFNGLCREATESHADERPROC glCreateShader = NULL;
glCreateShader = (PFNGLCREATESHADERPROC) wglGetProcAddress("glCreateShader");
or for Linux:
PFNGLCREATESHADERPROC glCreateShader = NULL;
glCreateShader = (PFNGLCREATESHADERPROC) glXGetProcAddress((GLubyte*) "glCreateShader");
If you define GL_GLEXT_PROTOTYPES before including glext.h you can omit the first line.
EDIT: SDL_opengl.h looks like it contains a copy of glext.h (not up to date though). So if you use that the above should still be valid. If you want to use a seperate glext.h you must define NO_SDL_GLEXT before including SDL_opengl.h. Also, the function prototypes aren't available as long as GL_GLEXT_PROTOTYPES isn't defined or you write them yourself.
EDIT2: Apparently SDL has its own GetProcAddress function called SDL_GL_GetProcAddress.
Can you load the addresses of the functions at runtime?
typedef GLhandle (APIENTRYP PFNGLCREATESHADERPROC) (GLenum shaderType);
PFNGLCREATESHADERPROC glCreateShader = NULL;
glCreateShader = (PFNGLCREATESHADERPROC)wglGetProcAddress("glCreateShader");
typedef GLhandle (APIENTRYP PFNGLCREATEPROGRAMPROC) ();
PFNGLCREATEPROGRAMPROC glCreateProgram = NULL;
glCreateProgram = (PFNGLCREATEPROGRAMPROC)wglGetProcAddress("glCreateProgram");