diff --git a/desmume/src/OGLRender.cpp b/desmume/src/OGLRender.cpp
index bc95d9c8c..9c7edb80b 100644
--- a/desmume/src/OGLRender.cpp
+++ b/desmume/src/OGLRender.cpp
@@ -1451,7 +1451,7 @@ static void OGLGetLine(int line, int start, int end_inclusive, u16* dst, u8* dst
 	//	u32 dstpixel;
 
 		dst[j] = (screen3D[t+2] | (screen3D[t+1] << 5) | (screen3D[t+0] << 10) | ((screen3D[t+3] > 0) ? 0x8000 : 0x0000));
-		dstAlpha[j] = (screen3D[t+3] / 2);
+		dstAlpha[j] = alpha_5bit_to_4bit[screen3D[t+3]];
 		
 		//old debug reminder: display alpha channel
 		//u32 r = screen3D[t+3];
diff --git a/desmume/src/gfx3d.cpp b/desmume/src/gfx3d.cpp
index 22bb7ab39..fedce1168 100644
--- a/desmume/src/gfx3d.cpp
+++ b/desmume/src/gfx3d.cpp
@@ -65,6 +65,25 @@ CACHE_ALIGN const u8 material_3bit_to_8bit[] = {
 	0x00, 0x24, 0x49, 0x6D, 0x92, 0xB6, 0xDB, 0xFF
 };
 
+CACHE_ALIGN const u8 alpha_5bit_to_4bit[] = {
+	0x00, 0x00,
+	0x01, 0x01,
+	0x02, 0x02,
+	0x03, 0x03,
+	0x04, 0x04,
+	0x05, 0x05,
+	0x06, 0x06,
+	0x07, 0x07,
+	0x08, 0x08,
+	0x09, 0x09,
+	0x0A, 0x0A,
+	0x0B, 0x0B,
+	0x0C, 0x0C,
+	0x0D, 0x0D,
+	0x0E, 0x0E,
+	0x10, 0x10
+};
+
 //private acceleration tables
 static float float16table[65536];
 static float float10Table[1024];
diff --git a/desmume/src/gfx3d.h b/desmume/src/gfx3d.h
index f1f19622d..f3dee07da 100644
--- a/desmume/src/gfx3d.h
+++ b/desmume/src/gfx3d.h
@@ -152,6 +152,7 @@ extern CACHE_ALIGN u8 mixTable555[32][32][32];
 extern CACHE_ALIGN const int material_5bit_to_31bit[32];
 extern CACHE_ALIGN const u8 material_5bit_to_8bit[32];
 extern CACHE_ALIGN const u8 material_3bit_to_8bit[8];
+extern CACHE_ALIGN const u8 alpha_5bit_to_4bit[32];
 
 //GE commands:
 void gfx3d_glViewPort(unsigned long v);