From 5d93d4d7e9d618a02a9cd535202ba3abdc337b84 Mon Sep 17 00:00:00 2001
From: Pavel Krajcevski <pavel@cs.unc.edu>
Date: Tue, 19 Nov 2013 15:01:54 -0500
Subject: [PATCH] Add option to flip image along Y-axis to accomodate different
 image formats.

---
 IO/config/ImageLoader.h.in |  2 +-
 IO/src/ImageLoader.cpp     | 13 ++++++++-----
 IO/src/ImageLoaderTGA.cpp  |  2 +-
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/IO/config/ImageLoader.h.in b/IO/config/ImageLoader.h.in
index 6250e0f..971bb89 100644
--- a/IO/config/ImageLoader.h.in
+++ b/IO/config/ImageLoader.h.in
@@ -94,7 +94,7 @@ class ImageLoader {
 
   uint32 GetChannelForPixel(uint32 x, uint32 y, uint32 ch);
 
-  bool LoadFromPixelBuffer(uint32 *data);
+  bool LoadFromPixelBuffer(uint32 *data, bool flipY = false);
 
  public:
   virtual ~ImageLoader() {
diff --git a/IO/src/ImageLoader.cpp b/IO/src/ImageLoader.cpp
index 8208ebc..37df083 100644
--- a/IO/src/ImageLoader.cpp
+++ b/IO/src/ImageLoader.cpp
@@ -137,7 +137,7 @@ unsigned int ImageLoader::GetChannelForPixel(uint32 x, uint32 y, uint32 ch) {
   return val;
 }
 
-bool ImageLoader::LoadFromPixelBuffer(uint32 *data) {
+bool ImageLoader::LoadFromPixelBuffer(uint32 *data, bool flipY) {
   m_RedChannelPrecision = 8;
   m_GreenChannelPrecision = 8;
   m_BlueChannelPrecision = 8;
@@ -152,11 +152,14 @@ bool ImageLoader::LoadFromPixelBuffer(uint32 *data) {
   for (uint32 i = 0; i < m_Width; i++) {
     for (uint32 j = 0; j < m_Height; j++) {
       uint32 idx = j*m_Height + i;
+      uint32 pIdx = idx;
+      if(flipY)
+        idx = (m_Height - j - 1)*m_Height + i;
       uint32 pixel = data[idx];
-      m_RedData[idx] = pixel & 0xFF;
-      m_GreenData[idx] = (pixel >> 8) & 0xFF;
-      m_BlueData[idx] = (pixel >> 16) & 0xFF;
-      m_AlphaData[idx] = (pixel >> 24) & 0xFF;
+      m_RedData[pIdx] = pixel & 0xFF;
+      m_GreenData[pIdx] = (pixel >> 8) & 0xFF;
+      m_BlueData[pIdx] = (pixel >> 16) & 0xFF;
+      m_AlphaData[pIdx] = (pixel >> 24) & 0xFF;
     }
   }
 
diff --git a/IO/src/ImageLoaderTGA.cpp b/IO/src/ImageLoaderTGA.cpp
index 5f04421..4f0ab09 100644
--- a/IO/src/ImageLoaderTGA.cpp
+++ b/IO/src/ImageLoaderTGA.cpp
@@ -76,6 +76,6 @@ bool ImageLoaderTGA::ReadData() {
 
   assert(static_cast<uint32>(tga.imageLength) == m_Width * m_Height * 4);
 
-  return LoadFromPixelBuffer(reinterpret_cast<uint32 *>(tga.image));
+  return LoadFromPixelBuffer(reinterpret_cast<uint32 *>(tga.image), true);
 }