meta: Fix transfer operations check in meta pbo path for readpixels

Currently used ctx->_ImageTransferState check is not sufficient
because it doesn't include the read color clamping enabled with
GL_CLAMP_READ_COLOR. So, use the helper function
_mesa_get_readpixels_transfer_ops().

Also, transfer operations don't affect glGetTexImage(). So, do
the check only for glReadPixles.

Without this patch, arb_color_buffer_float-readpixels test fails, when
forced to use meta pbo path.

V2: Add a comment and bump up the commit message.

Signed-off-by: Anuj Phogat <[email protected]>
Cc: <[email protected]>
Reviewed-by: Iago Toral Quiroga <[email protected]>
(cherry picked from commit 1252d53c19ec005c17ca666cecb7db072d77e5ce)

1 files changed, 9 insertions, 4 deletions

diff --git a/src/mesa/drivers/common/meta_tex_subimage.c b/src/mesa/drivers/common/meta_tex_subimage.c
index 6bd74e126f2..d2552c4425d 100644
--- a/src/mesa/drivers/common/meta_tex_subimage.c
+++ b/src/mesa/drivers/common/meta_tex_subimage.c
@@ -272,12 +272,17 @@ _mesa_meta_pbo_GetTexSubImage(struct gl_context *ctx, GLuint dims,
        format == GL_COLOR_INDEX)
       return false;
 
-   if (ctx->_ImageTransferState)
-      return false;
-
-
+   /* Don't use meta path for readpixels in below conditions. */
    if (!tex_image) {
       rb = ctx->ReadBuffer->_ColorReadBuffer;
+
+      /* _mesa_get_readpixels_transfer_ops() includes the cases of read
+       * color clamping along with the ctx->_ImageTransferState.
+       */
+      if (_mesa_get_readpixels_transfer_ops(ctx, rb->Format, format,
+                                            type, GL_FALSE))
+         return false;
+
       if (_mesa_need_rgb_to_luminance_conversion(rb->Format, format))
          return false;
    }