From e86dbe0f36209498f88375e17b30d8dd38419b46 Mon Sep 17 00:00:00 2001
From: Fabien Freling <public@ffreling.com>
Date: Wed, 2 Jul 2014 22:38:57 +0200
Subject: [PATCH] Factorize the computation of the source point.

---
 rotation.cpp | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/rotation.cpp b/rotation.cpp
index a6f69b4..a3255b1 100644
--- a/rotation.cpp
+++ b/rotation.cpp
@@ -761,16 +761,10 @@ void rotate_pixel(TiledImage<W, H> const& src, TiledImage<W, H>& rotated,
   // special case if we can directly map the src to the dest
   if (x_delta == 0 && y_delta == 0)
   {
-//    cout << "we can directly map, w00t" << endl;
     uint8_t* rot_tile = rotated.tiles[rot_tile_index];
     memcpy(&rot_tile[rot_index], src_index_1, 3 * sizeof (uint8_t));
     return;
   }
-//  cout << "src rotated point: " << src_rotated_point << endl;
-//  cout << "src rotated point y: " << src_rotated_point.y << endl;
-//  cout << "src rotated point y int: " << (int) src_rotated_point.y << endl;
-//  cout << "x delta = " << x_delta << endl;
-//  cout << "y delta = " << y_delta << endl;
 
   uint8_t const* src_index_2 = src.access_pixel((int) src_rotated_point.x + 1, (int) src_rotated_point.y);
   uint8_t const* src_index_3 = src.access_pixel((int) src_rotated_point.x, (int) src_rotated_point.y + 1);
@@ -842,18 +836,14 @@ TiledImage<W, H> rotate(TiledImage<W, H> const& src, double angle)
       for (unsigned int j = 0; j < H; ++j)
       {
         int const y_index = y * H + j;
+        int x_index = x * W;
+        DPoint src_rotated_point(rot_origin_in_src.x + x_index * src_delta_x.x + y_index * src_delta_y.x,
+                                 rot_origin_in_src.y + x_index * src_delta_x.y + y_index * src_delta_y.y);
 
-        for (unsigned int i = 0; i < W; ++i)
+        for (unsigned int i = 0; i < W; ++i, ++x_index)
         {
-//          cout << "rotated: tile[" << x << ", " << y << "] point(" << i << ", " << j << ")" << endl;
           unsigned int const rot_index = (j * W + i) * 3;
-          int const x_index = x * W + i;
           Point const rot_point(x_index, y_index);
-          DPoint src_rotated_point(rot_origin_in_src.x + x_index * src_delta_x.x + y_index * src_delta_y.x,
-                                   rot_origin_in_src.y + x_index * src_delta_x.y + y_index * src_delta_y.y);
-
-//          cout << "rotated tile index: " << rot_tile_index << endl;
-//          cout << "src point: " << src_rotated_point << endl;
 
           if (src_rotated_point.x < 0 || src_rotated_point.x > src.width
             || src_rotated_point.y < 0 || src_rotated_point.y > src.height)
@@ -863,6 +853,9 @@ TiledImage<W, H> rotate(TiledImage<W, H> const& src, double angle)
                        src_rotated_point,
                        rot_tile_index, rot_index);
 
+          src_rotated_point.x += src_delta_x.x;
+          src_rotated_point.y += src_delta_x.y;
+
         }
       }
     }
@@ -1036,9 +1029,9 @@ int main(int argc, char* argv[])
   }
 
   Image img(argv[1]);
-  TiledImage<16, 16> tiled_img(argv[1]);
+  TiledImage<32, 32> tiled_img(argv[1]);
 
-  for (double rotation = 0; rotation < 360; rotation += 450)
+  for (double rotation = 0; rotation < 360; rotation += 45)
   {
     // No tile
     auto const before = chrono::high_resolution_clock::now();