CODEWITHSUNDEEP
macosopenglswiftopengl-3
zacaj
zacaj

Reputation: 2065

Vertex Array Objcects - glGenVertexArrays GL_INVALID_OPERATION on OSX

I'm trying to get a simple OpenGL program going, but I can't get it to display anything. I'm using Swift on a Mac, neither of which I am familiar with, although I've got a good amount of experience with OpenGL on windows. The program runs fine (no GL errors or anything), but nothing displays, until I add this at the end of my openGL initialization:

var vao:GLuint=0;checkGlError();
glGenVertexArrays(1, &vao);checkGlError();
glBindVertexArray(vao);checkGlError();

Then, it gives GL_INVALID_OPERATION as soon as I call glGenVertexArrays(), however the docs don't mention that as an option.

I worried that I might not have a GL3 context (and really I'd prefer to just have a GL1/2 context, however the Swift headers seem to be missing things like glBegin() and glColor3f(), so I decided to settle for GL3), so I tried to manually request one:

required init?(coder: NSCoder) {
    super.init(coder: coder);
    let attribs=[NSOpenGLPFAOpenGLProfile,NSOpenGLProfileVersion3_2Core,0];
    pixelFormat=NSOpenGLPixelFormat(attributes: UnsafePointer<NSOpenGLPixelFormatAttribute>(attribs));
    openGLContext=NSOpenGLContext(format: pixelFormat, shareContext: nil);
    openGLContext.view=self;
    openGLContext.makeCurrentContext();
};

However this didn't seem to affect things at all.

Upvotes: 1

Views: 1616

Answers (2)

zacaj
zacaj

Reputation: 2065

I was able to solve this by creating a bridging header and including #include in that, then using a GL1 context.

Upvotes: 0

Andon M. Coleman
Andon M. Coleman

Reputation: 43319

First, glBegin (...) is not valid in a core profile context. You are going to need a legacy (non-core) context for that.

Now, since the legacy context is limited to OpenGL 2.1, it only offers GL_APPLE_vertex_array_object. In a 2.1 context, you can call glGenVertexArraysAPPLE (...) and glBindVertexArrayAPPLE (...) and they will do the same thing.

The problem you are encountering is that on OS X, you link to the same framework regardless which context version you get. That means that you can call functions that are not supported by your context at run-time. Any time you try to use a GL 3.2+ function from the legacy context, you get GL_INVALID_OPERATION.

Upvotes: 5

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