meta: Add an accelerated glCopyTexSubImage using glBlitFramebuffer.

You'll note from the previous commits that there's something of a loop
here: You call CTSI, which calls BlitFB, then if things go wrong that
falls back to CTSI.  As a result, meta CTSI reaches over into blitfb to
tell it "no, don't try that fallback".

v2: Drop the _mesa_update_state(), which was only necessary due to use of
    _mesa_clip_blit() in _mesa_meta_BlitFramebuffer() in another patch
    series.
v3: Drop an _EXT suffix I copy-and-pasted.

Reviewed-by: Ian Romanick <[email protected]> (v2)
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/mesa/drivers/common/meta_blit.c b/src/mesa/drivers/common/meta_blit.c
index d1c40f50c52..526295bacbd 100644
--- a/src/mesa/drivers/common/meta_blit.c
+++ b/src/mesa/drivers/common/meta_blit.c
@@ -419,6 +419,9 @@ blitframebuffer_texture(struct gl_context *ctx,
       /* Fall back to doing a CopyTexSubImage to get the destination
        * renderbuffer into a texture.
        */
+      if (ctx->Meta->Blit.no_ctsi_fallback)
+         return false;
+
       if (rb->NumSamples > 1)
          return false;