util: new util_format_get_nr_components helper

diff --git a/src/gallium/auxiliary/util/u_format.h b/src/gallium/auxiliary/util/u_format.h
index 2fbbb83d4ba14463a2f2ba3ebcb9f99c05cd498d..6345a11a8cfb12f88785e9925524a14c7ec8813f 100644 (file)
--- a/src/gallium/auxiliary/util/u_format.h
+++ b/src/gallium/auxiliary/util/u_format.h
@@ -404,6 +404,23 @@ util_format_has_alpha(enum pipe_format format)
    }
 }
 
+/**
+ * Return the number of components stored.
+ * Formats with block size != 1x1 will always have 1 component (the block).
+ */
+static INLINE unsigned
+util_format_get_nr_components(enum pipe_format format)
+{
+   const struct util_format_description *desc = util_format_description(format);
+   unsigned chan;
+   unsigned nr_comp = 0;
+   for (chan = 0; chan < 4; chan++) {
+      if (desc->channel[chan].size != 0) {
+         nr_comp++;
+      }
+   }
+   return nr_comp;
+}
 
 /*
  * Format access functions.