glew linking problems qt creator qmake - opengl

Question

I am trying to get a project working with SDL2, assimp, opengl, and glew and cannot get glew to link properly (almost a duplicate but a more comprehensive question and answer, I think).
My qmake .pro file :
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
HEADERS += \
objloader.h \
display.h \
eventloop.h \
shader.h \
texture.h
SOURCES += main.cpp \
objloader.cpp \
display.cpp \
eventloop.cpp \
shader.cpp \
texture.cpp
INCLUDEPATH += "C:/code middleware/glew-1.12.0/include/" \
"C:\code middleware\glm\\" \
"C:\code middleware\SDL2-2.0.3\include\\" \
"C:\Users\smart_000\Desktop\assimp\include\\"
DEPENDPATH += "C:/code middleware/glew-1.10.0/bin/Release\Win32/" \
"C:\code middleware\SDL2-2.0.3\lib/x86/" \
"C:/Users/smart_000/Desktop/assimp/bin/" \
"C:/code middleware/glew-1.12.0/lib/Release/Win32/" \
"C:/code middleware/glew-1.12.0/bin/Release/Win32/"
LIBS += -L"C:\code middleware\SDL2-2.0.3\lib\x86" -lSDL2main -lSDL2
LIBS += -L"C:/Users/smart_000/Desktop/assimp/lib/" -lassimp.dll -lzlib
LIBS += -lopengl32
LIBS += -lglu32
LIBS += -L"C:/code middleware/glew-1.12.0/lib/Release/Win32/" -lglew32 -lglu32
The linker errors I am getting: linker errors
What I have tried already:
Checking file path problems ('/' and '\' kind of stuff and spaces in file names etc.)
Linking dynamically and statically (Yes, I defined GLEW_STATIC where I needed to, and I linked to -lglew32s and such)
SDL stuff: messing with and defining 'NO_SDL_GLEXT' above it
Making test programs and trying to link it with just g++ (I used the -static flag where I should have when I tried the static one and placed the linker flags after the files that needed them). These errors were the same as the qt ones minus the warnings.
Putting the glew source code directly in my project and building it (exact same errors) --- The issues were eerily similar and made no sense to me. I had commented out the qmake stuff and re ran qmake; I wasn't aware I could get linker errors like that if I put it in my project like I did.
Running qmake after my changes, lol
Moving 'LIBS' and 'DEPENDPATH' around and added 'CONFIG += opengl' in desperation
Messing with debug and release builds.
What I haven't tried:
Moving libraries and things to the system path
MAKING SURE THE LIBRARIES WERE BUILT FOR MINGW!
The relevant code(I know it's terrible; I was just hacking around when I encountered these issues) :
"main.cpp" :
#include <GL/glew.h>
#include <iostream>
#include <SDL.h>
#include <objloader.h>
#include "display.h"
#include "eventloop.h"
Display* display = NULL;
void callback()
{
std::cout << "yay" << std::endl;
display->Swap();
}
int main(int argc, char* argv[])
{
UShortVector indices;
Vec3Vector vertices;
Vec2Vector uvs;
Vec3Vector normals;
bool success = ObjLoader::loadObj("cube.obj", indices, vertices, uvs, normals);
display = new Display();
EventLoop eventLoop;
eventLoop.SetLoopCallback(&callback);
display->Create("yay");
eventLoop.Start();
return 0;
}
"display.h"
#ifndef DISPLAY_H
#define DISPLAY_H
#include <GL/glew.h>
#include <SDL.h>
#include <iostream>
class Display
{
public:
Display();
~Display();
void Create(const char* title);
void Swap();
SDL_Window* window_ = NULL;
SDL_GLContext glContext_;
};
#endif // DISPLAY_H
"shader.h"
#ifndef SHADER_H
#define SHADER_H
#include <GL/glew.h>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <memory.h>
class Shader
{
public:
GLuint LoadShaders(const char * vertex_file_path, const char * fragment_file_path);
private:
Shader();
~Shader();
};
#endif // SHADER_H
"shader.cpp"
#include "shader.h"
Shader::Shader()
{
}
Shader::~Shader()
{
}
GLuint Shader::LoadShaders(const char * vertexShaderPath, const char * fragmentShaderPath)
{
FILE* vertexFile = fopen(vertexShaderPath, "r");
FILE* fragmentFile = fopen(fragmentShaderPath, "r");
if(!vertexFile || !fragmentFile)
{
if(!vertexFile)
{
perror("could not open the vertex shader file");
}
if(!fragmentFile)
{
perror("could not open the fragment shader file");
}
}
GLuint programID = glCreateProgram();
GLuint vertShader = glCreateShader(GL_VERTEX_SHADER);
GLuint fragShader = glCreateShader(GL_FRAGMENT_SHADER);
const size_t MAX_LINE_LENGTH = 120;
char line[MAX_LINE_LENGTH];
std::vector<GLchar*> vertShaderSource;
std::vector<GLchar*> fragmentShaderSource;
while(fgets(line, MAX_LINE_LENGTH, vertexFile) != NULL)
{
vertShaderSource.push_back((GLchar*)line);
memset((void*)line, '\0', sizeof(line));
}
while(fgets(line, MAX_LINE_LENGTH, fragmentFile) != NULL)
{
fragmentShaderSource.push_back((GLchar*)line);
memset((void*)line, '\0', sizeof(line));
}
glShaderSource(vertShader, vertShaderSource.size(), (const GLchar**)&vertShaderSource, NULL);
glShaderSource(fragShader, fragmentShaderSource.size(), (const GLchar**)&fragmentShaderSource, NULL);
// doesn't do anything at the moment, I know. It should still compile though.
return programID;
}

Answer 1

Right after I posted the question, I found the issue. Embarrassingly, it was an issue I have run into before with assimp (although I just now realized why re-building it with cmake worked).
The hallmarks:
Weird linker errors with a library when you know the library is being found.
You primarily work on a windows system :)
The solution:
Check the build kit that you are using with Qt creator Vs. the libs you are using.
I was using the MINGW one only and my libs were compiled using the MSVC++ compiler
The libs you are looking for are .a files: specifically lib{name}.a . In this case, I was looking for libglew32.dll.a <- note the .dll in there for whether it is a dll import library or a static one like libglew32s.a <- note the s for static.
Where to go to get the rights libs :
- Go here for building it: Building glew on windows with mingw.
- Go here to download the pre-built one that I did (older version of glew): https://launchpad.net/glew-cmake/+milestone/1.10.0
The Download link that I used: glew-gcc-1.10.0-win32.zip (md5) Glew-Cmake 1.10.0 Binaries (MinGW) <- I tried to post a picture, but apparently, I am not cool enough to do that yet.
My updated and working qmake .pro file :
TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
HEADERS += \
objloader.h \
display.h \
eventloop.h \
shader.h \
texture.h
SOURCES += main.cpp \
objloader.cpp \
display.cpp \
eventloop.cpp \
shader.cpp \
texture.cpp
INCLUDEPATH += "C:/code middleware/glew-gcc-1.10.0-win32/include/" \
"C:/code middleware/glm/" \
"C:/code middleware/SDL2-2.0.3/include/" \
"C:/Users/smart_000/Desktop/assimp/include/"
DEPENDPATH += "C:/code middleware/SDL2-2.0.3/lib/x86/" \
"C:/Users/smart_000/Desktop/assimp/bin/" \
"C:/code middleware/glew-gcc-1.10.0-win32/lib/" \
"C:/code middleware/glew-gcc-1.10.0-win32/bin/"
LIBS += -L"C:/code middleware/SDL2-2.0.3/lib/x86" -lSDL2main -lSDL2
LIBS += -L"C:/Users/smart_000/Desktop/assimp/lib/" -lassimp.dll -lzlib
LIBS += -L"C:/code middleware/glew-gcc-1.10.0-win32/lib/" -lglew32.dll
LIBS += -lopengl32
LIBS += -lglu32
Note: Don't forget the .dll on the end of the libs (-lglew32.dll).
- Happy Linking!