diff --git a/desmume/src/OGLRender.cpp b/desmume/src/OGLRender.cpp
index a8e48584b..e3683feb0 100755
--- a/desmume/src/OGLRender.cpp
+++ b/desmume/src/OGLRender.cpp
@@ -336,7 +336,7 @@ static const char *GeometryFragShader_100 = {"\
 		float vertW = (vtxPosition.w == 0.0) ? 0.00000001 : vtxPosition.w;\n\
 		float depthOffset = (polyDepthOffsetMode == 0) ? 0.0 : ((polyDepthOffsetMode == 1) ? -DEPTH_EQUALS_TEST_TOLERANCE : DEPTH_EQUALS_TEST_TOLERANCE);\n\
 		// hack: when using z-depth, drop some LSBs so that the overworld map in Dragon Quest IV shows up correctly\n\
-		float newFragDepthValue = (stateUseWDepth) ? clamp( ( floor(vtxPosition.w * 4096.0) + depthOffset ) / 16777215.0, 0.0, 1.0 ) : clamp( ( (floor(clamp(((vtxPosition.z/vertW) * 0.5 + 0.5), 0.0, 1.0) * 32767.0) * 512.0) + depthOffset ) / 16777215.0, 0.0, 1.0 );\n\
+		float newFragDepthValue = (stateUseWDepth) ? clamp( ( (vtxPosition.w * 4096.0) + depthOffset ) / 16777215.0, 0.0, 1.0 ) : clamp( ( (floor(((vtxPosition.z/vertW) * 0.5 + 0.5) * 4194303.0) * 4.0) + depthOffset ) / 16777215.0, 0.0, 1.0 );\n\
 		\n\
 		if ((polyMode != 3) || polyDrawShadow)\n\
 		{\n\
diff --git a/desmume/src/OGLRender_3_2.cpp b/desmume/src/OGLRender_3_2.cpp
index b1a6d8fbf..1f8688d94 100644
--- a/desmume/src/OGLRender_3_2.cpp
+++ b/desmume/src/OGLRender_3_2.cpp
@@ -207,7 +207,7 @@ static const char *GeometryFragShader_150 = {"\
 		float vertW = (vtxPosition.w == 0.0) ? 0.00000001 : vtxPosition.w;\n\
 		float depthOffset = (polyDepthOffsetMode == 0) ? 0.0 : ((polyDepthOffsetMode == 1) ? -DEPTH_EQUALS_TEST_TOLERANCE : DEPTH_EQUALS_TEST_TOLERANCE);\n\
 		// hack: when using z-depth, drop some LSBs so that the overworld map in Dragon Quest IV shows up correctly\n\
-		float newFragDepthValue = (state.useWDepth) ? clamp( ( floor(vtxPosition.w * 4096.0) + depthOffset ) / 16777215.0, 0.0, 1.0 ) : clamp( ( (floor(clamp(((vtxPosition.z/vertW) * 0.5 + 0.5), 0.0, 1.0) * 32767.0) * 512.0) + depthOffset ) / 16777215.0, 0.0, 1.0 );\n\
+		float newFragDepthValue = (state.useWDepth) ? clamp( ( (vtxPosition.w * 4096.0) + depthOffset ) / 16777215.0, 0.0, 1.0 ) : clamp( ( (floor(((vtxPosition.z/vertW) * 0.5 + 0.5) * 4194303.0) * 4.0) + depthOffset ) / 16777215.0, 0.0, 1.0 );\n\
 		\n\
 		if ((polyMode != 3u) || polyDrawShadow)\n\
 		{\n\
diff --git a/desmume/src/rasterize.cpp b/desmume/src/rasterize.cpp
index 330c15586..f59923a91 100644
--- a/desmume/src/rasterize.cpp
+++ b/desmume/src/rasterize.cpp
@@ -517,7 +517,7 @@ FORCEINLINE void RasterizerUnit<RENDERER>::_pixel(const POLYGON_ATTR polyAttr, c
 	// When using z-depth, be sure to test against the following test cases:
 	// - The drawing of the overworld map in Dragon Quest IV
 	// - The drawing of all units on the map in Advance Wars: Days of Ruin
-	const u32 newDepth = (gfx3d.renderState.wbuffer) ? u32floor(4096*w) : (u32floor(z*0x7FFF) << 9);
+	const u32 newDepth = (gfx3d.renderState.wbuffer) ? u32floor(w * 4096.0f) : u32floor(z * 16777215.0f);
 	
 	// run the depth test
 	bool depthFail = false;