[Mesa-dev] [PATCH 06/15] intel: Add intel_mipmap_tree::singlesample_mt

[Chad Versace]

This miptree will be used only for storing the singlesample data of
multisample window system buffers.

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_mipmap_tree.c |  1 +
 src/mesa/drivers/dri/intel/intel_mipmap_tree.h | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
index d6572cd..56e936e 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
@@ -435,6 +435,7 @@ intel_miptree_release(struct intel_mipmap_tree **mt)
       intel_miptree_release(&(*mt)->stencil_mt);
       intel_miptree_release(&(*mt)->hiz_mt);
       intel_miptree_release(&(*mt)->mcs_mt);
+      intel_miptree_release(&(*mt)->singlesample_mt);
       intel_resolve_map_clear(&(*mt)->hiz_map);
 
       for (i = 0; i < MAX_TEXTURE_LEVELS; i++) {
diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
index cfd671e..e5e89f0 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
@@ -248,6 +248,29 @@ struct intel_mipmap_tree
    uint32_t offset;
 
    /**
+    * \brief Singlesample miptree.
+    *
+    * This is used only for multisample window system front and back buffers.
+    *
+    * Suppose that the window system FBO was created with a multisample
+    * config.  Let back_rb be the intel_renderbuffer for the FBO's back
+    * buffer. Then back_rb contains two miptrees: a parent multisample miptree
+    * (back_rb->mt) and a child singlesample miptree
+    * (back_rb->mt->singlesample_mt).  The DRM buffer shared with DRI2 belongs
+    * to back_rb->mt->singlesample_mt and contains singlesample data.
+    *
+    * When access to the singlesample data is needed, such as at
+    * eglSwapBuffers and glReadPixels, an automatic downsample occurs from
+    * back_rb->mt to back_rb->mt->singlesample_mt when necessary.
+    */
+   struct intel_mipmap_tree *singlesample_mt;
+
+   /**
+    * \brief A downsample is needed from this miptree to singlesample_mt.
+    */
+   bool need_downsample;
+
+   /**
     * \brief HiZ miptree
     *
     * This is non-null only if HiZ is enabled for this miptree.
-- 
1.7.11.2