Framebuffer incomplete attachment

Question

I am creating a framebuffer in LWJGL using:

        framebuffer = glGenFramebuffers();
        texture = glGenTextures();
        glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
        glBindTexture(GL_TEXTURE_2D, texture);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, texture, 0);
        glDrawBuffers(GL_COLOR_ATTACHMENT0);

But glCheckFramebufferStatus tells me that the attachment is incomplete. What am I doing wrong? I checked several websites and I don't seem to be missing anything...?

Answer 1

I assume that you want to draw into a colour attachment (the texture). Let me recommend a short look into the documentation (https://khronos.org/registry/OpenGL-Refpages/gl4/) and chapter 9 of the specification (https://www.khronos.org/registry/OpenGL/specs/gl/glspec45.core.pdf) on how framebuffers and their attachments (renderbuffers) are being set up for drawing.

Here's example code to generate a framebuffer with a single colour attachment for rendering (OpenGL 4.5, plain C, no error handling for brevity):

// Create the framebuffer
glCreateFramebuffers( 1, &framebuffer );
// Create a colour attachment
glCreateRenderbuffers( 1, &color_attachment );
// make room (check formats for your need)
glNamedRenderbufferStorage( color_attachment, internal_format, size_x, size_y );
// attach renderbuffer to framebuffer; just a single colour attachment
glNamedFramebufferRenderbuffer( framebuffer, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color_attachment );
// check for completeness
if( GL_FRAMEBUFFER_COMPLETE != glCheckNamedFramebufferStatus( framebuffer, GL_FRAMEBUFFER ) {
        /* error message;*/
}

when needed, bind the buffer to its target with a call to:

glBindFramebuffer( GL_DRAW_FRAMEBUFFER, framebuffer );

to draw into it.

Cleanup with a call to glDeleteRenderbuffers and glDeleteFramebuffers.

Use the glNamedFramebufferParameteri and glNamedRenderbufferParameteri functions for specific adjustments.