How does OpenGL function loading work?
Where are the functions actually located? This is implementation dependent. I'd wager that they're stored in a hash table of function names to function pointers. They're still in the shared library, but usually don't have their symbols exposed. How are they retrieved? glXGetProcAddress or wglGetProcAddress, depending on the platform....
SDL2 OpenGL 4.2 context with 0 color bits and 0 depth bits
c++,opengl,graphics,sdl-2,glew
I'm using SDL's built-in function SDL_GL_GetAttribute which returns the values that SDL uses to create the context, not the actual context attributes (as I understand it). This is incorrect, I took a look at the SDL implementation of SDL_GL_GetAttribute (...) (see src/video/SDL_video.c) and it does what I described. You...
GLEW and my shader disagree - do I have that extension or not?
opengl,glsl,glew,opengl-extensions
GL_ARB_robustness is not a GLSL modifying extension. The intention of this extension is to make the interaction with the OpenGL API more robust in the sense that out-of-bound accesses to memory can be caught. Somewhat like the difference between sprintf and snprintf. Since this is not a shader extension it...
How to make macbook pro recognize GLEW and GLFW?
If you get an error related to including the header file, the compiler cannot find the header. You can pass the -v flag to GCC (incl. g++) or Clang (incl. clang++) to see information about where it’s looking for it. As this forum post explains, if you receive these link...
glActiveTexture in Qt and QGLWidget?
qt,opengl,glew,qglwidget,qt5.3
For anything beyond GL 1.1 (and glActiveTexture is beyond that), you have to use OpenGL's extension mechanism. Qt can do that for you all under the hood, have a look at the QAbstractOpenGLFunctions class hierarchy You can get the context the widget has created via QOpenGLWidget::context and the QAbstractOpenGLFunctions of...
Access violation at glTranslate() call
So it was an access violation at the glDrawArrays call, not the glTranslatef call. And it occurred because of uninitialized buffers :(.
GLEW and glfw compile error: undefined reference to symbol 'XConvertSelection'
Ok, after some research I found that the DSO error which I got means that the order of the includes I've implemented is incorrect and cause the compilation to fail. So what I did is I used the command: pkg-config --static --libs x11 xrandr xi xxf86vm glew glfw3 To get...
GLUI controls do not appear but they have effect
opengl,visual-c++,glew,freeglut,glui
Could it be, that you created a OpenGL-3 core profile context? GLUI uses functionality deprecated in OpenGL-3 and unless you have a compatibility context it will not work at all. Also remember, that GLUI doesn't know shaders, so if you use shaders, remember to disable them after you're done using...
SDL OpenGL window not responding, transparent
Setting the pixel format properties after you create your context is pretty pointless. The pixel format of the default framebuffer is immutable once the context is created. Move all your calls to SDL_GL_SetAttribute (...) so that they come before SDL_GL_CreateContext(window). The swap interval can be set at any time, but...
How do you add libraries to CMakeLists?
The way to include the libraries depends on a few things. Some packages such as sdl2 have pkgconfig files that define the libraries and includes to use. Cmake comes with a FindPkgConfig module that can get it for you. For example: include(FindPkgConfig) pkg_check_modules(SDL2 REQUIRED sdl2) target_link_libraries(executablename ${SDL2_LIBRARIES}) You can also...
Use OpenGL without a window [duplicate]
I use OpenGL with GLFW + GLEW in a multi-platform system [Windows, Mac and Linux]. The error you are having smells like missing: glewExperimental = GL_TRUE; Google for it so you can understand a little more. What platform are you on?...
Glew does not init
You don't have a GL context just by glfwInit(), so GLEW has nothing to work on. You must create a GL context and make it current to the thread, which for GLFW implies creating a window.
XCode linking static library (GLEW) attempts dylib load
xcode,osx,static-libraries,glew
It looks like something else was actually happening here. When I built the static GLEW library, it also built the dynamic version right next to it. Based on some other searches I made online, it seems that Xcode will automatically attempt to load up the dynamic version of a library,...
GLEW + cmake linking fails “undefined reference to symbol glDrawElements” + “DSO missing from command line”
The problem was that in OpenGL_INCLUDE_DIRS and OpenGL_LIRARIES is actually OPENGL_INCLUDE_DIRS (<-- not quite sure I need that one, I probably don't) and OPENGL_LIBRARY So the CmakeFile snippet I had in my question should actually look like this find_package(OpenGL) find_package(GLEW) find_package(SDL2) find_package(Assimp) #Include(FindPkgConfig) #PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2) set(INCLUDE_DIRS ${INCLUDE_DIRS} ${OPENGL_INCLUDE_DIRS} ${SDL2_INCLUDE_DIRS}...
glew linking problems qt creator qmake
opengl,linker,qt-creator,qmake,glew
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...
glewInit() and GLEW_ARB_xxx_ failure in client program
I actually would not make a point of initializing GLEW from your dummy context. Consider manually loading the one or two extensions you need to create your final context by hand (e.g. WGL_ARB_create_context and WGL_ARB_pixel_format). You are not guaranteed to get the same ICD implementation on Windows when you create...
How to draw indices in c++ Opengl
Not sure if I spotted everything, but here are a few issues that jumped out: Wrong argument to glGenBuffers(): glGenBuffers(1, &vbo); glGenBuffers(2, &ibo); In the second call, you also want to generate only one buffer name, so it should be: glGenBuffers(1, &vbo); glGenBuffers(1, &ibo); Wrong size for vertex buffer: glBufferData(GL_ARRAY_BUFFER,...
GLEW_APPLE_GLX Causes Linking Error When Building GLEW
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...
GLEW unknown type name
You have an extra h at the begining of hPFNGLQUERYOBJECTPARAMETERUIAMDPROC, it has to be PFNGLQUERYOBJECTPARAMETERUIAMDPROC without the leading h.
Glew's glewIsSupported(“GL_VERSION_3_1”) returning false on MBP OSX 10.10.1 with NVIDIA GeForce GT 650M
This happens on more than just OS X, it's because GLEW has poor support for Open GL core contexts. For example, this also happens on my Linux system with Mesa: it reports version 3.0, even though 3.3 is actually supported. On OS X, I recommend the following: You must create...
Why is glFramebufferTexture a NULL pointer when GLEW_ARB_framebuffer_object is non-zero?
glFramebufferTexture() is a newer entry point than glBindFramebuffer() and other FBO related entry points. In the core OpenGL spec, glFramebufferTexture() was added in 3.2, while the rest of the FBO functionality was part of 3.0. glFramebufferTexture() was also not part of ARB_framebuffer_object. You can use glFramebufferTexture2D() in most cases, which...
error LNK1104: cannot open file 'glew32.lib'
Visual Studio doesn't look into the subfolders of the directories you specified in Additional Library Directories. That means that you have to add the exact path where the library is stored (which would be in your case H:\#DEV\OpenGL\glew-1.12.0\lib\Release\Win32)....
GL3W error on compilation
The functions you're trying to use (e.g, glBegin(), glVertex…(), etc) are part of the OpenGL compatibility profile. They are not present in the OpenGL core profile, which is what gl3w provides. It sounds like this may not be what you actually want here. If so, don't use gl3w....
Go Lang OpenGL simple shape - blank screen
I finally figured out what my problem was in this code. The first thing I had to do was positionAttrib := program.GetAttribLocation("vertexPosition_modelspace") for all the input variables going into the vertex shader. This was done after binding the VBO for each array. Next, If you notice my code above: gl.BufferData(gl.ARRAY_BUFFER,...
Can't draw anything in openGL using GLEW (mac,c++)
Looking at the tutorial, it seems that you're missing the VAO. Specifically, you should add these lines after you initialize GLEW. GLuint VertexArrayID; glGenVertexArrays(1, &VertexArrayID); glBindVertexArray(VertexArrayID); Then, in your call to VertexAttribPointer, your attribute should be 0, not 1. So the call shoud look like this glVertexAttribPointer( 0, // attribute...
glDraw* returning GL_INVALID_ENUM
That is because GL_QUADS has been deprecated in OpenGL 3, see the documentation for glDrawArrays. You can either: Draw triangles (recommended). Create your opengl context using a compatiblity profile. (How to do this exactly depends on what you are using to create the context in the first place, SDL, glfw,...
nsight - OpenGL 4.2 debugging incompatibility
For anyone interested, Nsight captures all commands issued to the OpenGL server. Not just those issued through your application. If you have any FPS or recording software enabled, these tend to use deprecated methods drawing to the framebuffer. In my case it was Riva Tuner which displays the FPS on...
Difference between glewGetString(GLEW_VERSION) and glewIsSupported
These two methods do not return the same information: glGetString(GLEW_VERSION) returns the version of the GLEW library, not the OpenGL Version used. In contrast, glewIsSupported checks whether a OpenGL Version is supported or not. In order to get the OpenGL Version used in a context, one can use the glGetIntegerv...
FreeGlut OpenGL Context Version
c++,opengl,graphics,glew,freeglut
I fixed it myself: Only the order of my code was wrong. The actual opt-in to a OpenGL 4 (or 4.1 in this particular case) happens after calling glutCreateWindow("Window Title"), surprisingly not after glutInitContextVersion(major, minor). However putting the code: glewExperimental = GL_TRUE; GLenum err = glewInit(); if (GLEW_OK != err)...
GLEW can't find GL version
As jozxyqk said, I had to create a GL context before I initialized GLEW.
getting segmentation fault (core dumped) with my sdl2 opengl code in c
Since the comment solved OPs problem I'm making this a full answer close is a operating system level function being specified in the POSIX standard; I really got puzzled by your stacktrace, why there would be a close doing a glDeleteProgram. Please don't use any names specified for OS level...
How do I set a variable to point to more than one file
Use list values, which are separated by semicolons: cmake -DGLEW_LIBRARIES=%GLEWDIR%\lib\Release\x64\glew32.lib;%GLEWDIR%\lib\Release\x64\glew32s.lib And in CMake: target_link_libraries(my_executable ${GLEW_LIBRARIES}) Note that %GLEWDIR% might not get interpreted correctly in this context....
OpenGL Batch render Mesh
Since glVertexPointer() (and the other gl<Foo>Pointer() calls) are deprecated in OpenGL 3 and later, I'm assuming that you're not currently using an OpenGL 3+ core profile. There are two methods of instanced rendering which are potentially available, both provided via extensions; ARB_Draw_Instanced and ARB_Instanced_Arrays. Either, both, or neither might be...
GLSL Deprecation
GLSL shader version and context version are two separate things, by the way. It is true that gl_ModelViewProjectionMatrix is deprecated after GLSL 1.20 (introduced in GL 2.1) because GL 3.0 deprecated (and GL 3.1 without GL_ARB_compatibility removed) the entire fixed-function matrix stack. GLSL version 1.50 introduces profiles to GLSL, which...
Glew undefined reference linking error
Fixed it. Somewhere along the lines I had got glu32 which glew was using instead of the windows ones I compiled. Added a reference to glew32 and it worked fine....
Why am I not getting a forward compatible OpenGL context with GLFW?
I should get the maximum available OpenGL context on the running machine, provided that it's above OpenGL 3.3. That's not the way it is defined. From the GLFW documentation: The GLFW_CONTEXT_VERSION_MAJOR and GLFW_CONTEXT_VERSION_MINOR hints specify the client API version that the created context must be compatible with. For OpenGL,...
Why am I getting an undefined reference in this code?
c++,opengl,linker,undefined-reference,glew
MinGW does not like the binary dynamic library that ships with glew for Windows, it will only work with Visual C++ unless you do a lot of unnecessarily complicated things to it. The far simpler solution is to remove -lglew32 from your build commandline, keep -lglew32s (static library) and add...
Can't compile OpenGL project under OSX
c++,osx,opengl,osx-yosemite,glew
The EXT variant will only be defined in glext.h or the headers which come or are generated by the various GL extenstion loaders. The actual GL_TEXTURE_BUFFER enum is defined in OpenGL/gl3.h. On OSX, modern GL is part of the OS, and you can directly link the modern GL funtions. However,...