GLDEPTHATTACHMENT

GL_DEPTH_ATTACHMENT is an OpenGL framebuffer attachment point used to designate the depth buffer storage for a framebuffer object (FBO). It is not a texture format itself; rather, it identifies where depth data should be stored when rendering to an FBO.

Attachments to an FBO can be made with either textures or renderbuffers. A depth texture or a depth renderbuffer can be bound to the GL_DEPTH_ATTACHMENT point using appropriate calls such as attaching a texture with a texture target (for example, GL_TEXTURE_2D or GL_TEXTURE_3D) or attaching a renderbuffer. The depth attachment works in conjunction with other attachments, such as color attachments, to define the complete framebuffer.

GL_DEPTH_ATTACHMENT is one of several framebuffer attachment points. In addition to color attachments (GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, etc.), there is GL_DEPTH_ATTACHMENT for depth data and GL_STENCIL_ATTACHMENT for stencil data. There is also GL_DEPTH_STENCIL_ATTACHMENT for combined depth and stencil buffers. A framebuffer can have a depth attachment or a combined depth-stencil attachment, and it must be complete according to the rules of framebuffer completeness.

When a depth attachment is present, the depth test during rendering writes depth values to that buffer, enabling depth comparisons against existing depth data. If the depth texture is bound, it can also be sampled in shaders for advanced effects such as shadow mapping or depth-based effects. The default framebuffer is not configured via GL_DEPTH_ATTACHMENT; this mechanism applies to offscreen rendering with FBOs.

Common considerations include ensuring the depth attachment matches the framebuffer’s size and format requirements, and choosing between a depth texture (for sampling) or a depth renderbuffer (for simple depth testing only).