Fix wrong iteration order

Author: kevyuu

include/nbl/core/algorithm/radix_sort.h

@@ -84,16 +84,18 @@ struct RadixLsbSorter
 
 			// count
 			constexpr histogram_t shift = static_cast<histogram_t>(radix_bits*pass_ix);
-			for (histogram_t i = 0u; i < rangeSize; i++)
+			for (histogram_t i = rangeSize; i != 0;)
+			{
+				i--;
 				++m_histogram[comp.template operator()<shift,radix_mask>(input[i])];
+			}
 
 			// prefix sum
 			std::exclusive_scan(m_histogram, m_histogram + histogram_size, m_histogram, 0);
 
 			// scatter. After scatter m_histogram now become a skiplist
-			for (histogram_t i = rangeSize; i != 0;)
+			for (histogram_t i = 0; i < rangeSize; i++)
 			{
-				i--;
         const auto& val = input[i];
         const auto& histogramIx = comp.template operator()<shift,radix_mask>(val);
         output[m_histogram[histogramIx]++] = val;