From e72a032a114c7710112534157abad8fa300c2f7d Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Sun, 19 Jun 2016 23:12:10 +0200
Subject: [PATCH] Fixed alpha channel issue with textures

---
 src/textures/pngtexture.cpp | 10 ++++++++--
 src/textures/texture.cpp    |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/textures/pngtexture.cpp b/src/textures/pngtexture.cpp
index 206797a34..408cf1e2f 100644
--- a/src/textures/pngtexture.cpp
+++ b/src/textures/pngtexture.cpp
@@ -724,8 +724,9 @@ void FPNGTexture::MakeTextureBgra ()
 				{
 					for (y = Height; y > 0; --y)
 					{
+						// output as premultiplied alpha
 						uint32_t alpha = in[1];
-						uint32_t gray = in[0];
+						uint32_t gray = (in[0] * alpha + 127) / 255;
 						*out++ = (alpha << 24) | (gray << 16) | (gray << 8) | gray;
 						in += pitch;
 					}
@@ -740,7 +741,12 @@ void FPNGTexture::MakeTextureBgra ()
 				{
 					for (y = Height; y > 0; --y)
 					{
-						*out++ = (((uint32_t)in[3]) << 24) | (((uint32_t)in[0]) << 16) | (((uint32_t)in[1]) << 8) | ((uint32_t)in[2]);
+						// output as premultiplied alpha
+						uint32_t alpha = in[3];
+						uint32_t red = (in[0] * alpha + 127) / 255;
+						uint32_t green = (in[1] * alpha + 127) / 255;
+						uint32_t blue = (in[2] * alpha + 127) / 255;
+						*out++ = (alpha << 24) | (red << 16) | (green << 8) | blue;
 						in += pitch;
 					}
 					in -= backstep;
diff --git a/src/textures/texture.cpp b/src/textures/texture.cpp
index 0030719cb..da5dd8ad7 100644
--- a/src/textures/texture.cpp
+++ b/src/textures/texture.cpp
@@ -203,7 +203,7 @@ const uint32_t *FTexture::GetPixelsBgra()
 		PixelsBgra.resize(Width * Height);
 		for (int i = 0; i < Width * Height; i++)
 		{
-			PixelsBgra[i] = GPalette.BaseColors[indices[i]].d;
+			PixelsBgra[i] = 0xff000000 | GPalette.BaseColors[indices[i]].d;
 		}
 	}
 	return PixelsBgra.data();