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.
0 kommentar(er)
