OpenGL texture array layer data copy

Question

I'm trying to copy a slice from one OpenGL texture array to another. I'd like to do this on the GPU without resubmitting anything from the CPU if possible. (This is pretty easy to do in D3D, but I'm new to modern OpenGL.)

The closest I've been able to get, based on google and StackOverflow searches, is below. This almost works, except it only copies from the first slice in the source array (to the correct slice of the destination array). I tried using glFramebufferTexture3D so I could specify the source slice (the commented line), but that generates GL_INVALID_ENUM if I use GL_TEXTURE_2D_ARRAY for the textarget parameter, and GL_INVALID_OPERATION if I use GL_TEXTURE_3D.

GLuint fb;
glGenFramebuffers(1, &fb);
glBindFramebuffer(GL_READ_FRAMEBUFFER, fb);

glFramebufferTexture(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, src_texture_handle, 0);
//glFramebufferTexture3D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_ARRAY, src_texture_handle, 0, src_slice);
glReadBuffer(GL_COLOR_ATTACHMENT0);
glCopyTextureSubImage3D(dst_texture_handle, 0, 0, 0, dst_slice, 0, 0, width, height);

glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
glDeleteFramebuffers(1, &fb);

Answer 1

I'm trying to copy a slice from one OpenGL texture array to another.

Then the function you should be using is glCopyImageSubData. glCopyTextureSubImage copies from the framebuffer. glCopyImageSubData copies from one texture to another.

Answer 2

The correct command to attach a specific layer of a 2D array texture to a framebuffer is glFrameBufferTextureLayer.