It can be unnecessary at best and unsupported at worst (e.g. no ARB_texture_multisample).
-- v2: wined3d: Don't force going through a texture when downloading from renderbuffers. wined3d: Handle depth textures in texture2d_read_from_framebuffer(). wined3d: Rename wined3d_context_gl_apply_fbo_state_blit() function. wined3d: Factor out a wined3d_context_gl_apply_blit_state_fb() function. wined3d: Don't call wined3d_texture_load() from wined3d_context_gl_apply_blit_state(). wined3d: Don't bind the FBO to GL_READ_FRAMEBUFFER in wined3d_context_gl_apply_blit_state(). wined3d: Don't call wined3d_context_gl_apply_blit_state() from texture2d_read_from_framebuffer().