From a6ef15ea62fc1273a488b4ffe1c6ce65bc445c80 Mon Sep 17 00:00:00 2001
From: Fabien Freling <public@ffreling.com>
Date: Sun, 6 Jul 2014 23:47:21 +0200
Subject: [PATCH] Create PackedPixel structure.

---
 rotation.cpp | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/rotation.cpp b/rotation.cpp
index e7f6a87..a46e9f7 100644
--- a/rotation.cpp
+++ b/rotation.cpp
@@ -39,6 +39,24 @@ std::basic_ostream<Elem, Traits>& operator << (std::basic_ostream<Elem, Traits>&
   return o;
 }
 
+struct PackedPixel {
+  uint32_t r;
+  uint32_t g;
+  uint32_t b;
+
+  PackedPixel()
+  : r(0)
+  , g(0)
+  , b(0)
+  {}
+};
+
+uint8_t interpolate_packed(uint32_t pack, double x, double x_inv, double y, double y_inv)
+{
+  return (((pack >> 24) & 0x000f) * x_inv + ((pack >> 16) & 0x000f) * x) * y_inv
+         + (((pack >> 8) & 0x000f) * x_inv + (pack & 0x000f) * x) * y;
+}
+
 
 
 //
@@ -311,6 +329,31 @@ struct TiledImage : public Image {
     return tile + tile_j * tile_width + (tile_i * 3);
   }
 
+  PackedPixel
+  get_packed_pixels(unsigned int x, unsigned int y) const
+  {
+    PackedPixel pack;
+
+    this->insert_pixel(pack, x, y);
+    pack.r = pack.r << 8;
+    pack.g = pack.g << 8;
+    pack.b = pack.b << 8;
+
+    this->insert_pixel(pack, x + 1, y);
+    pack.r = pack.r << 8;
+    pack.g = pack.g << 8;
+    pack.b = pack.b << 8;
+
+    this->insert_pixel(pack, x, y + 1);
+    pack.r = pack.r << 8;
+    pack.g = pack.g << 8;
+    pack.b = pack.b << 8;
+
+    this->insert_pixel(pack, x + 1, y + 1);
+
+    return pack;
+  }
+
   void
   print_tile(unsigned int index) const
   {
@@ -334,6 +377,21 @@ struct TiledImage : public Image {
 
 
   protected:
+    void insert_pixel(PackedPixel& pack, unsigned int x, unsigned int y) const
+    {
+      unsigned int const tile_width = tile_w * 3;
+      unsigned int const tile_index = (y / tile_h) * nb_col_tile + (x / tile_w);
+      if (tile_index >= nb_col_tile * nb_row_tile)
+        return;
+      uint8_t const* tile = tiles[tile_index];
+      unsigned int const tile_j = y % tile_h;
+      unsigned int const tile_i = x % tile_w;
+      unsigned int index = tile_j * tile_width + (tile_i * 3);
+      pack.r += tile[index];
+      pack.g += tile[index + 1] + 1;
+      pack.b += tile[index + 2] + 1;
+    }
+
     void allocate_memory(unsigned int w, unsigned int h)
     {
       width = w;