By default OpenGL chooses GL_LESS which means that if the depth value of an object is less than that of the current depth value, then the first value replaces the second. We can do this by using the glDepthFunc and inserting one of the following inputs. Using this depth information, we can asses which object should be in front of which other object. A depth value of 0 meaning that it's right on the near plane, and of 1 meaning it's on the far plane. Now what this buffer basically does, is that it stores "depth" values that represent how far away from the near plane of the projection matrix a certain fragment is. Since the buffer is turned off by default, we want to make sure we have it enabled, and that we clear it each frame just like the Color Buffer. You might remember that we've already made use of the Depth Buffer in the "Going 3D" tutorial in order to fix a weird issue we had. In this tutorial we'll take a look at Depth Buffers in OpenGL and also see how we can make use of them for a little graphical effect. And that should be all you need to know about this course, enjoy!
If you don't know what OpenGL is or are not familiar with it, then you should first watch the beginners course for OpenGL which you can find on this channel. Hi everyone! In this course I'll teach you about different advanced topics in OpenGL that will help you achieve more complex effects, better looking renders, and more optimized scenes. This advanced OpenGL course from Victor Gordan will take your skills to the next level. OpenGl can be used to create complex graphics effects. Watch the course below or on the YouTube channel (1-hour watch). Here are the topics covered in this course: Now, he will help you take your skills to the next level. Before this course he created one of the most popular OpenGL course on YouTube. We just released an advanced OpenGL course on the YouTube channel. What probably happened was that your compiler optimized the one you didn't write to out, so it kinda forgot about it when it came time to check for linker errors.OpenGL can be used to create complex 2D and 3D graphics effects. Now to be fair, your program should have failed to link when you used two outputs that didn't get different output locations. However, the OpenGL standard does not require this behavior, so you should not depend on it either. If you don't do any explicit assignments, implementations usually will assign one of your output variables to location 0. There are also the API functions glBindFragDataLocation and glGetFragDataLocation, which are analogous to glBindAttribLocation and glGetAttribLocation. It's set very similarly to vertex shader input locations: layout(location = 1) out secColor
This process begins with the fragment output location value. Therefore, you need to indicate which output goes to which fragment output color. Fragment shaders can write to multiple output colors, which themselves get mapped to multiple buffers in the framebuffer. In any case, fragment shader outputs work almost exactly the same way. Setting it in the shader is almost always the better option. If you don't explicitly provide an attribute location, GLSL will assign a location arbitrarily (ie: in an implementation-defined manner). Before 3.30 (or without ARB_explicit_attrib_location), you would have to either set this up explicitly with glBindAttrbLocation before linking or query the program for the attribute index with glGetAttribLocation. This sets the color vertex shader input to come from attribute location 2. In GLSL 3.30, you use this syntax: layout(location = 2) in color Remember how, in vertex shaders, you have inputs? And these inputs represent vertex attribute indices, the numbers you pass to glVertexAttribPointer and glEnableVertexAttribArray and so forth? You set up which input pulls from which attribute. Now, back to user-defined fragment shader outputs. Unless you're using compatibility (in which case, your 3.30 shaders should say #version 330 compatibility at the top), you should never use this. That was removed from core OpenGL 3.1 and above. No, you don't have the predefined gl_FragColor. Furthermore, we have a predefined gl_FragColor.