mesa: add format-helper for latc

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18564>

src/mesa/main/formats.c

@@ -665,6 +665,16 @@ _mesa_is_format_rgtc(mesa_format format)
 }
 
 
+/**
+ * Return TRUE if format is an LATC compressed format.
+ */
+bool
+_mesa_is_format_latc(mesa_format format)
+{
+   return _mesa_get_format_layout(format) == MESA_FORMAT_LAYOUT_LATC;
+}
+
+
 /**
  * Return TRUE if format is an BPTC compressed format.
  */

src/mesa/main/formats.h

@@ -701,6 +701,9 @@ _mesa_is_format_s3tc(mesa_format format);
 bool
 _mesa_is_format_rgtc(mesa_format format);
 
+bool
+_mesa_is_format_latc(mesa_format format);
+
 bool
 _mesa_is_format_bptc(mesa_format format);