diff --git a/rotation.cpp b/rotation.cpp
index aa3ee57..6b232c4 100644
--- a/rotation.cpp
+++ b/rotation.cpp
@@ -340,15 +340,13 @@ void rotate_pixel(Image const& src,
   int const src_y = src_rotated_point.y >> q_pow;
 
   // Bilinear interpolation
-  unsigned int const src_index_1 = (src_y * src.width + src_x) * src.pixel_size;
-  unsigned int const src_index_2 = src_index_1 + src.pixel_size;
-  unsigned int const src_index_3 = src_index_1 + src.pixel_size * src.width;
-  unsigned int const src_index_4 = src_index_3 + src.pixel_size;
+  unsigned int const src_index_1 = src_y * src.width + src_x;
+  unsigned int const src_index_3 = src_index_1 + src.width;
 
   pvalue_t const src_tl = src.buffer[src_index_1];
-  pvalue_t const src_tr = src.buffer[src_index_2];
+  pvalue_t const src_tr = src.buffer[src_index_1 + 1];
   pvalue_t const src_bl = src.buffer[src_index_3];
-  pvalue_t const src_br = src.buffer[src_index_4];
+  pvalue_t const src_br = src.buffer[src_index_3 + 1];
 
   unsigned int const x_delta = (src_rotated_point.x >> (q_pow - q_inter_pow)) & mask;
   unsigned int const y_delta = (src_rotated_point.y >> (q_pow - q_inter_pow)) & mask;
@@ -402,7 +400,7 @@ Image* rotate(Image const& src, double angle)
   round_if_very_small(src_delta_y.x);
   round_if_very_small(src_delta_y.y);
 
-  // Quantized position on a grid
+  // Quantized position on a 1024x1024 grid
   int const q_pos_pow = 10;
   int const q_pos = 1 << q_pos_pow;