You have to compute the matrix manually and then pass it to OpenGL. Computing the matrix This snippet of code is based on the gluPerspective documentation. void BuildPerspProjMat(float *m, float fov, float aspect, float znear, float zfar) { float f = 1/tan(fov * PI_OVER_360); m[0] = f/aspect; m[1] = 0; m[2] = 0; m[3] = … Read more
Performance improvements. In many cases, setting up your attributes on the host require a high number of API calls, and an important amount of validation inside the implementation. Doing all those once, and using the VAO allow that work to be amortized. See, for example, Graham Sellers’ analysis for actual data.
Stay away from NeHe, the tutorials are hopelessly outdated and contain a lot of “problematic” stuff, too. For starting with 3.x, try those, they’re both up-to-date: Aurian (Joe Groff) Arcsynthesis (Jason L. McKesson) Update: Re-reading my own post almost 2 years later, I guess that one might find that it sounds a bit harsh. This … Read more
glEnableVertexAttribArray(program.getAttrib(“in_Position”)); // A call to getGLError() at this point prints nothing. glVertexAttribPointer(program.getAttrib(“in_Position”), 3, GL_FLOAT, GL_FALSE, 0, 0); // A call to getGLError() at this point prints “OpenGL error 1282”. First, there’s an obvious driver bug here, because glEnableVertexAttribArray should also have issued a GL_INVALID_OPERATION error. Or you made a mistake when you checked it. Why … Read more
I cordially dislike negative answers, but I’m afraid I have to give one to this question. You are ultimately asking for beginner material that uses features unique to OpenGL version 4.0 and above. Well, let’s look at some of the unique features of 4.x. Perhaps the biggest feature is tessellation. What does that mean? It … Read more
I would not advise to try actual ray tracing in OpenGL because you need a lot hacks and tricks for that and, if you ask me, there is not a point in doing this anymore at all. If you want to do ray tracing on GPU, you should go with any GPGPU language, such as … Read more
VAOs act similarly to VBOs and textures with regard to how they are bound. Having a single VAO bound for the entire length of your program will yield no performance benefits because you might as well just be rendering without VAOs at all. In fact it may be slower depending on how the implementation intercepts … Read more