From fbbf87a36f5f27851a2e2d17b95a0f17dd82624b Mon Sep 17 00:00:00 2001
From: Andrei Karas <akaras@inbox.ru>
Date: Sun, 17 May 2015 19:48:30 +0300
Subject: Fix possible issues in texture atlas creation with non power of two
 image sizes.

---
 src/resources/openglimagehelper.cpp | 55 +++++++++++++++++++++++++++++++++++--
 src/resources/openglimagehelper.h   |  3 ++
 2 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/src/resources/openglimagehelper.cpp b/src/resources/openglimagehelper.cpp
index 4c7095ec8..ca553a180 100644
--- a/src/resources/openglimagehelper.cpp
+++ b/src/resources/openglimagehelper.cpp
@@ -134,8 +134,8 @@ int OpenGLImageHelper::powerOfTwo(const int input)
     return value >= mTextureSize ? mTextureSize : value;
 }
 
-SDL_Surface *OpenGLImageHelper::convertSurface(SDL_Surface *tmpImage,
-                                               int width, int height)
+SDL_Surface *OpenGLImageHelper::convertSurfaceNormalize(SDL_Surface *tmpImage,
+                                                        int width, int height)
 {
     if (!tmpImage)
         return nullptr;
@@ -193,6 +193,55 @@ SDL_Surface *OpenGLImageHelper::convertSurface(SDL_Surface *tmpImage,
     return tmpImage;
 }
 
+SDL_Surface *OpenGLImageHelper::convertSurface(SDL_Surface *tmpImage,
+                                               int width, int height)
+{
+    if (!tmpImage)
+        return nullptr;
+
+#ifdef USE_SDL2
+    SDL_SetSurfaceAlphaMod(tmpImage, SDL_ALPHA_OPAQUE);
+#else
+    // Make sure the alpha channel is not used, but copied to destination
+    SDL_SetAlpha(tmpImage, 0, SDL_ALPHA_OPAQUE);
+#endif
+
+    // Determine 32-bit masks based on byte order
+    uint32_t rmask, gmask, bmask, amask;
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+    rmask = 0xff000000;
+    gmask = 0x00ff0000;
+    bmask = 0x0000ff00;
+    amask = 0x000000ff;
+#else
+    rmask = 0x000000ff;
+    gmask = 0x0000ff00;
+    bmask = 0x00ff0000;
+    amask = 0xff000000;
+#endif
+
+    if (tmpImage->format->BitsPerPixel != 32
+        || rmask != tmpImage->format->Rmask
+        || gmask != tmpImage->format->Gmask
+        || amask != tmpImage->format->Amask)
+    {
+        SDL_Surface *oldImage = tmpImage;
+#ifdef USE_SDL2
+        SDL_SetSurfaceBlendMode(oldImage, SDL_BLENDMODE_NONE);
+#endif
+        tmpImage = MSDL_CreateRGBSurface(SDL_SWSURFACE, width, height,
+            32, rmask, gmask, bmask, amask);
+
+        if (!tmpImage)
+        {
+            logger->log("Error, image convert failed: out of memory");
+            return nullptr;
+        }
+        SDL_BlitSurface(oldImage, nullptr, tmpImage, nullptr);
+    }
+    return tmpImage;
+}
+
 void OpenGLImageHelper::bindTexture(const GLuint texture)
 {
     switch (mUseOpenGL)
@@ -241,7 +290,7 @@ Image *OpenGLImageHelper::glLoad(SDL_Surface *tmpImage,
         height = tmpImage->h;
 
     SDL_Surface *oldImage = tmpImage;
-    tmpImage = convertSurface(tmpImage, width, height);
+    tmpImage = convertSurfaceNormalize(tmpImage, width, height);
 
     const int realWidth = tmpImage->w;
     const int realHeight = tmpImage->h;
diff --git a/src/resources/openglimagehelper.h b/src/resources/openglimagehelper.h
index 1afebb736..758817684 100644
--- a/src/resources/openglimagehelper.h
+++ b/src/resources/openglimagehelper.h
@@ -135,6 +135,9 @@ class OpenGLImageHelper final : public ImageHelper
          */
         static int powerOfTwo(const int input) A_WARN_UNUSED;
 
+        static SDL_Surface *convertSurfaceNormalize(SDL_Surface *tmpImage,
+                                                    int width, int height);
+
         static SDL_Surface *convertSurface(SDL_Surface *tmpImage,
                                            int width, int height);
 
-- 
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