diff --git a/desmume/src/OGLRender.cpp b/desmume/src/OGLRender.cpp
index d75ea542d..c23afbeab 100755
--- a/desmume/src/OGLRender.cpp
+++ b/desmume/src/OGLRender.cpp
@@ -1,7 +1,7 @@
 /*
 	Copyright (C) 2006 yopyop
 	Copyright (C) 2006-2007 shash
-	Copyright (C) 2008-2018 DeSmuME team
+	Copyright (C) 2008-2019 DeSmuME team
 
 	This file is free software: you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
@@ -294,7 +294,8 @@ void main() \n\
 	\n\
 	vtxTexCoord = texScaleMtx * inTexCoord0; \n\
 	vtxColor = vec4(inColor / 63.0, polyAlpha); \n\
-	gl_Position = inPosition; \n\
+	gl_Position.xyw = inPosition.xyw;\n\
+	gl_Position.z = (inPosition.z + inPosition.w) / 2.0;\n\
 } \n\
 "};
 
@@ -419,10 +420,10 @@ void main()\n\
 		#endif\n\
 	#else\n\
 		#if ENABLE_W_DEPTH\n\
-		gl_FragDepth = clamp( (4096.0/gl_FragCoord.w) / 16777215.0, 0.0, 1.0 );\n\
+		gl_FragDepth = (4096.0/gl_FragCoord.w) / 16777215.0;\n\
 		#else\n\
 		// hack: when using z-depth, drop some LSBs so that the overworld map in Dragon Quest IV shows up correctly\n\
-		gl_FragDepth = clamp( (floor(gl_FragCoord.z * 4194303.0) * 4.0) / 16777215.0, 0.0, 1.0 );\n\
+		gl_FragDepth = (floor(gl_FragCoord.z * 4194303.0) * 4.0) / 16777215.0;\n\
 		#endif\n\
 	#endif\n\
 #endif\n\
diff --git a/desmume/src/OGLRender_3_2.cpp b/desmume/src/OGLRender_3_2.cpp
index 729a40023..d6a57a410 100755
--- a/desmume/src/OGLRender_3_2.cpp
+++ b/desmume/src/OGLRender_3_2.cpp
@@ -146,7 +146,8 @@ void main()\n\
 	\n\
 	vtxTexCoord = texScaleMtx * inTexCoord0;\n\
 	vtxColor = vec4(inColor / 63.0, polyAlpha);\n\
-	gl_Position = inPosition;\n\
+	gl_Position.xyw = inPosition.xyw;\n\
+	gl_Position.z = (inPosition.z + inPosition.w) / 2.0;\n\
 }\n\
 "};
 
@@ -290,10 +291,10 @@ void main()\n\
 		#endif\n\
 	#else\n\
 		#if ENABLE_W_DEPTH\n\
-		gl_FragDepth = clamp( (4096.0/gl_FragCoord.w) / 16777215.0, 0.0, 1.0 );\n\
+		gl_FragDepth = (4096.0/gl_FragCoord.w) / 16777215.0;\n\
 		#else\n\
 		// hack: when using z-depth, drop some LSBs so that the overworld map in Dragon Quest IV shows up correctly\n\
-		gl_FragDepth = clamp( (floor(gl_FragCoord.z * 4194303.0) * 4.0) / 16777215.0, 0.0, 1.0 );\n\
+		gl_FragDepth = (floor(gl_FragCoord.z * 4194303.0) * 4.0) / 16777215.0;\n\
 		#endif\n\
 	#endif\n\
 #endif\n\