util: when packing depth values, round to nearest.

This patch adds the lrint, lrintf, llrint, and llrintf rounding utility
functions. When packing unorm depth values, we will round to nearest.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index 702d4e9..478a4aa 100644
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -162,7 +162,59 @@ float log2f(float f)
 #endif
 
 
+#if __STDC_VERSION__ < 199901L && !defined(__cplusplus)
+static INLINE long int
+lrint(double d)
+{
+   long int rounded = (long int)(d + 0.5);
+
+   if (d - floor(d) == 0.5) {
+      if (rounded % 2 != 0)
+         rounded += (d > 0) ? -1 : 1;
+   }
+
+   return rounded;
+}
+
+static INLINE long int
+lrintf(float f)
+{
+   long int rounded = (long int)(f + 0.5f);
+
+   if (f - floorf(f) == 0.5f) {
+      if (rounded % 2 != 0)
+         rounded += (f > 0) ? -1 : 1;
+   }
+
+   return rounded;
+}
 
+static INLINE long long int
+llrint(double d)
+{
+   long long int rounded = (long long int)(d + 0.5);
+
+   if (d - floor(d) == 0.5) {
+      if (rounded % 2 != 0)
+         rounded += (d > 0) ? -1 : 1;
+   }
+
+   return rounded;
+}
+
+static INLINE long long int
+llrintf(float f)
+{
+   long long int rounded = (long long int)(f + 0.5f);
+
+   if (f - floorf(f) == 0.5f) {
+      if (rounded % 2 != 0)
+         rounded += (f > 0) ? -1 : 1;
+   }
+
+   return rounded;
+}
+#endif /* C99 */
 
 #define POW2_TABLE_SIZE_LOG2 9
 #define POW2_TABLE_SIZE (1 << POW2_TABLE_SIZE_LOG2)