[Mesa-dev] [PATCH 06/16] intel: Allocate miptree for multisample DRI2 buffers (v2)

[Chad Versace]

Immediately after obtaining, with DRI2GetBuffersWithFormat, the DRM buffer
handle for a DRI2 buffer, we wrap that DRM buffer handle with a region and
a miptree. This patch additionally allocates an accompanying multisample
miptree if the DRI2 buffer is multisampled.

Since we do not yet advertise multisample GL configs, the code for
allocating the multisample miptree is currently inactive.

v2:
    - Fix typo 'miptre'.
    - Upsample when rendering to the front buffer, per Paul.

CC: Eric Anholt <eric at anholt.net>
CC: Paul Berry <stereotype441 at gmail.com>
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 src/mesa/drivers/dri/intel/intel_context.c     | 27 ++++++++----
 src/mesa/drivers/dri/intel/intel_mipmap_tree.c | 59 ++++++++++++++++++++++++++
 src/mesa/drivers/dri/intel/intel_mipmap_tree.h |  7 +++
 3 files changed, 85 insertions(+), 8 deletions(-)

diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c
index 378859c..b32daa3 100644
--- a/src/mesa/drivers/dri/intel/intel_context.c
+++ b/src/mesa/drivers/dri/intel/intel_context.c
@@ -893,14 +893,24 @@ intel_process_dri2_buffer(struct intel_context *intel,
    if (!rb)
       return;
 
+   unsigned num_samples = rb->Base.Base.NumSamples;
+
    /* We try to avoid closing and reopening the same BO name, because the first
     * use of a mapping of the buffer involves a bunch of page faulting which is
     * moderately expensive.
     */
-   if (rb->mt &&
-       rb->mt->region &&
-       rb->mt->region->name == buffer->name)
-      return;
+   if (num_samples == 0) {
+       if (rb->mt &&
+           rb->mt->region &&
+           rb->mt->region->name == buffer->name)
+          return;
+   } else {
+       if (rb->mt &&
+           rb->mt->singlesample_mt &&
+           rb->mt->singlesample_mt->region &&
+           rb->mt->singlesample_mt->region->name == buffer->name)
+          return;
+   }
 
    if (unlikely(INTEL_DEBUG & DEBUG_DRI)) {
       fprintf(stderr,
@@ -920,9 +930,10 @@ intel_process_dri2_buffer(struct intel_context *intel,
    if (!region)
       return;
 
-   rb->mt = intel_miptree_create_for_region(intel,
-                                            GL_TEXTURE_2D,
-                                            intel_rb_format(rb),
-                                            region);
+   rb->mt = intel_miptree_create_for_dri2_buffer(intel,
+                                                 buffer->attachment,
+                                                 intel_rb_format(rb),
+                                                 num_samples,
+                                                 region);
    intel_region_release(&region);
 }
diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
index 3767c9d..e7cf10b 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
@@ -25,6 +25,9 @@
  * 
  **************************************************************************/
 
+#include <GL/gl.h>
+#include <GL/internal/dri_interface.h>
+
 #include "intel_batchbuffer.h"
 #include "intel_context.h"
 #include "intel_mipmap_tree.h"
@@ -324,6 +327,62 @@ compute_msaa_layout(struct intel_context *intel, gl_format format)
    }
 }
 
+/**
+ * For a singlesample DRI2 buffer, this simply wraps the given region with a miptree.
+ *
+ * For a multisample DRI2 buffer, this wraps the given region with
+ * a singlesample miptree, then creates a multisample miptree into which the
+ * singlesample miptree is embedded as a child.
+ */
+struct intel_mipmap_tree*
+intel_miptree_create_for_dri2_buffer(struct intel_context *intel,
+                                     unsigned dri_attachment,
+                                     gl_format format,
+                                     uint32_t num_samples,
+                                     struct intel_region *region)
+{
+   struct intel_mipmap_tree *singlesample_mt = NULL;
+   struct intel_mipmap_tree *multisample_mt = NULL;
+   GLenum base_format = _mesa_get_format_base_format(format);
+
+   /* Only the front and back buffers, which are color buffers, are shared
+    * through DRI2.
+    */
+   assert(dri_attachment == __DRI_BUFFER_BACK_LEFT ||
+          dri_attachment == __DRI_BUFFER_FRONT_LEFT ||
+          dri_attachment == __DRI_BUFFER_FAKE_FRONT_LEFT);
+   assert(base_format == GL_RGB || base_format == GL_RGBA);
+
+   singlesample_mt = intel_miptree_create_for_region(intel, GL_TEXTURE_2D,
+                                                     format, region);
+   if (!singlesample_mt)
+      return NULL;
+
+   if (num_samples == 0)
+      return singlesample_mt;
+
+   multisample_mt = intel_miptree_create_for_renderbuffer(intel,
+                                                          format,
+                                                          region->width,
+                                                          region->height,
+                                                          num_samples);
+   if (!multisample_mt) {
+      intel_miptree_release(&singlesample_mt);
+      return NULL;
+   }
+
+   multisample_mt->singlesample_mt = singlesample_mt;
+   multisample_mt->need_downsample = false;
+
+   if (intel->is_front_buffer_rendering &&
+       (dri_attachment == __DRI_BUFFER_FRONT_LEFT ||
+        dri_attachment == __DRI_BUFFER_FAKE_FRONT_LEFT)) {
+      intel_miptree_upsample(intel, multisample_mt);
+   }
+
+   return multisample_mt;
+}
+
 struct intel_mipmap_tree*
 intel_miptree_create_for_renderbuffer(struct intel_context *intel,
                                       gl_format format,
diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
index ca345bf..4ee68be 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
@@ -381,6 +381,13 @@ intel_miptree_create_for_region(struct intel_context *intel,
 				gl_format format,
 				struct intel_region *region);
 
+struct intel_mipmap_tree*
+intel_miptree_create_for_dri2_buffer(struct intel_context *intel,
+                                     unsigned dri_attachment,
+                                     gl_format format,
+                                     uint32_t num_samples,
+                                     struct intel_region *region);
+
 /**
  * Create a miptree appropriate as the storage for a non-texture renderbuffer.
  * The miptree has the following properties:
-- 
1.7.11.4