[Mesa-dev] [v2 05/19] i965: Add helper for detecting lossless compression

[Topi Pohjolainen]

Signed-off-by: Topi Pohjolainen <topi.pohjolainen at intel.com>
---
 src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 26 ++++++++++++++++++++++++++
 src/mesa/drivers/dri/i965/intel_mipmap_tree.h |  4 ++++
 2 files changed, 30 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
index 5f739d9..31de1ff 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
@@ -266,6 +266,32 @@ intel_miptree_supports_non_msrt_fast_clear(struct brw_context *brw,
       return true;
 }
 
+/* On Gen9 support for color buffer compression was extended to single
+ * sampled surfaces. This is a helper considering both auxiliary buffer
+ * type and number of samples telling if the given miptree represents
+ * the new single sampled case - also called lossless compression.
+ */
+bool
+intel_miptree_is_lossless_compressed(const struct brw_context *brw,
+                                     const struct intel_mipmap_tree *mt)
+{
+   /* Only available from Gen9 onwards. */
+   if (brw->gen < 9)
+      return false;
+
+   /* Compression always requires auxiliary buffer. */
+   if (!mt->mcs_mt)
+      return false;
+
+   /* Single sample compression is represented re-using msaa compression
+    * layout type: "Compressed Multisampled Surfaces".
+    */
+   if (mt->msaa_layout != INTEL_MSAA_LAYOUT_CMS)
+      return false;
+
+   /* And finally distinguish between msaa and single sample case. */
+   return mt->num_samples <= 1;
+}
 
 /**
  * Determine depth format corresponding to a depth+stencil format,
diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
index 64f73ea..13d4d7e 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
@@ -667,6 +667,10 @@ intel_get_non_msrt_mcs_alignment(struct intel_mipmap_tree *mt,
                                  unsigned *width_px, unsigned *height);
 
 bool
+intel_miptree_is_lossless_compressed(const struct brw_context *brw,
+                                     const struct intel_mipmap_tree *mt);
+
+bool
 intel_miptree_alloc_non_msrt_mcs(struct brw_context *brw,
                                  struct intel_mipmap_tree *mt);
 
-- 
2.5.0