diff --git a/source/build/src/polymost.cpp b/source/build/src/polymost.cpp
index 5373b5086..6674765e6 100644
--- a/source/build/src/polymost.cpp
+++ b/source/build/src/polymost.cpp
@@ -2075,6 +2075,7 @@ void polymost_drawrooms()
     GLInterface.EnableDepthTest(true);
 	GLInterface.SetDepthFunc(DF_LEqual);
     GLInterface.SetRenderStyle(LegacyRenderStyles[STYLE_Translucent]);
+    renderSetViewpoint(0, 0, 0);
 
     gvrcorrection = viewingrange*(1.f/65536.f);
     //if (glprojectionhacks == 2)
diff --git a/source/core/rendering/scene/hw_walls.cpp b/source/core/rendering/scene/hw_walls.cpp
index 47e35d1d3..4730e3835 100644
--- a/source/core/rendering/scene/hw_walls.cpp
+++ b/source/core/rendering/scene/hw_walls.cpp
@@ -921,7 +921,7 @@ void HWWall::DoMidTexture(HWDrawInfo* di, walltype* wal,
 //==========================================================================
 void HWWall::Process(HWDrawInfo *di, walltype *wal, sectortype* frontsector, sectortype* backsector)
 {
-	auto backwall = wall->nextwall >= 0 && wall->nextwall < numwalls? &wall[wal->nextwall] : nullptr;
+	auto backwall = wal->nextwall >= 0 && wal->nextwall < numwalls? &wall[wal->nextwall] : nullptr;
 	auto p2wall = &wall[wal->point2];
 
 	float fch1;
diff --git a/source/glbackend/glbackend.cpp b/source/glbackend/glbackend.cpp
index bf3667eee..f967a8923 100644
--- a/source/glbackend/glbackend.cpp
+++ b/source/glbackend/glbackend.cpp
@@ -189,6 +189,7 @@ bool PolymostRenderState::Apply(FRenderState& state, GLState& oldState)
 	else
 	{
 		state.EnableFog(0);
+		state.SetFog(0, 0);
 		state.SetSoftLightLevel(ShadeDiv >= 1 / 1000.f ? 255 - Scale(Shade, 255, numshades) : 255);
 		state.SetLightParms(VisFactor, ShadeDiv / (numshades - 2));
 	}
@@ -391,7 +392,7 @@ void renderSetVisibility(float vis)
 
 void renderSetViewpoint(float x, float y, float z)
 {
-	vp.mCameraPos = {x, y, z, 0};
+	vp.mCameraPos = {x, z, y, 0};
 }
 
 void renderBeginScene()