diff --git a/desmume/src/OGLRender.cpp b/desmume/src/OGLRender.cpp
index 5944ec282..b5ee2c2a4 100644
--- a/desmume/src/OGLRender.cpp
+++ b/desmume/src/OGLRender.cpp
@@ -331,7 +331,8 @@ static const char *fragmentShader_100 = {"\
 			discard; \n\
 		} \n\
 		\n\
-		gl_FragDepth = (oglWBuffer) ? vtxPosition.w/4096.0 : vtxPosition.z/4096.0; \n\
+		float vertW = (vtxPosition.w == 0.0f) ? 0.00000001f : vtxPosition.w; \n\
+		gl_FragDepth = (oglWBuffer) ? vtxPosition.w/4096.0 : (vtxPosition.z / vertW) * 0.5 + 0.5; \n\
 		gl_FragColor = fragColor; \n\
 	} \n\
 "};
diff --git a/desmume/src/OGLRender_3_2.cpp b/desmume/src/OGLRender_3_2.cpp
index 543ab9e2b..902ba4c43 100644
--- a/desmume/src/OGLRender_3_2.cpp
+++ b/desmume/src/OGLRender_3_2.cpp
@@ -181,7 +181,8 @@ static const char *fragmentShader_150 = {"\
 			discard; \n\
 		} \n\
 		\n\
-		gl_FragDepth = (oglWBuffer) ? vtxPosition.w/4096.0 : vtxPosition.z/4096.0; \n\
+		float vertW = (vtxPosition.w == 0.0f) ? 0.00000001f : vtxPosition.w; \n\
+		gl_FragDepth = (oglWBuffer) ? vtxPosition.w/4096.0 : (vtxPosition.z / vertW) * 0.5 + 0.5; \n\
 		outFragColor = fragColor; \n\
 	} \n\
 "};