diff --git a/source/Generating/Noise3DGenerator.cpp b/source/Generating/Noise3DGenerator.cpp
index 42a0d70d9..79138aa9f 100644
--- a/source/Generating/Noise3DGenerator.cpp
+++ b/source/Generating/Noise3DGenerator.cpp
@@ -61,14 +61,36 @@ void Debug3DNoise(NOISE_DATATYPE * a_Noise, int a_SizeX, int a_SizeY, int a_Size
 			f2.Write(buf, a_SizeX);
 		}  // for y
 	}  // if (XZ file open)
-	//*/
-
 }
 
 
 
 
 
+void Debug2DNoise(NOISE_DATATYPE * a_Noise, int a_SizeX, int a_SizeY, const AString & a_FileNameBase)
+{
+	const int BUF_SIZE = 512;
+	ASSERT(a_SizeX <= BUF_SIZE);  // Just stretch it, if needed
+	
+	cFile f1;
+	if (f1.Open(Printf("%s (%d).grab", a_FileNameBase.c_str(), a_SizeX), cFile::fmWrite))
+	{
+		for (int y = 0; y < a_SizeY; y++)
+		{
+			int idx = y * a_SizeX;
+			unsigned char buf[BUF_SIZE];
+			for (int x = 0; x < a_SizeX; x++)
+			{
+				buf[x] = (unsigned char)(std::min(255, std::max(0, (int)(128 + 32 * a_Noise[idx++]))));
+			}
+			f1.Write(buf, a_SizeX);
+		}  // for y
+	}  // if (file open)
+}
+
+
+
+
 /*
 // Perform an automatic test of upscaling upon program start (use breakpoints to debug):
 
@@ -78,6 +100,7 @@ public:
 	Test(void)
 	{
 		DoTest1();
+		DoTest2();
 	}
 	
 	
@@ -88,11 +111,26 @@ public:
 		{
 			In[i] = (float)(i % 5);
 		}
-		Debug3DNoise(In, 3, 3, 3, "Upscale in");
+		Debug3DNoise(In, 3, 3, 3, "Upscale3D in");
 		float Out[17 * 33 * 35];
 		LinearUpscale3DArray(In, 3, 3, 3, Out, 8, 16, 17);
-		Debug3DNoise(Out, 17, 33, 35, "Upscale test");
+		Debug3DNoise(Out, 17, 33, 35, "Upscale3D test");
 	}
+	
+	
+	void DoTest2(void)
+	{
+		float In[3 * 3];
+		for (int i = 0; i < ARRAYCOUNT(In); i++)
+		{
+			In[i] = (float)(i % 5);
+		}
+		Debug2DNoise(In, 3, 3, "Upscale2D in");
+		float Out[17 * 33];
+		LinearUpscale2DArray(In, 3, 3, Out, 8, 16);
+		Debug2DNoise(Out, 17, 33, "Upscale2D test");
+	}
+	
 } gTest;
 //*/
 
diff --git a/source/LinearUpscale.h b/source/LinearUpscale.h
index 60aa005bd..9f40b5d81 100644
--- a/source/LinearUpscale.h
+++ b/source/LinearUpscale.h
@@ -88,49 +88,59 @@ template<typename TYPE> void LinearUpscale2DArray(
 	int a_UpscaleX, int a_UpscaleY   ///< Upscale factor for each direction
 )
 {
+	// For optimization reasons, we're storing the upscaling ratios in a fixed-size arrays of these sizes
+	// Feel free to enlarge them if needed, but keep in mind that they're on the stack
+	const int MAX_UPSCALE_X = 128;
+	const int MAX_UPSCALE_Y = 128;
+	
 	ASSERT(a_Src != NULL);
 	ASSERT(a_Dst != NULL);
 	ASSERT(a_SrcSizeX > 0);
 	ASSERT(a_SrcSizeY > 0);
 	ASSERT(a_UpscaleX > 0);
 	ASSERT(a_UpscaleY > 0);
+	ASSERT(a_UpscaleX <= MAX_UPSCALE_X);
+	ASSERT(a_UpscaleY <= MAX_UPSCALE_Y);
 	
-	// First interpolate columns (same-Y) where the anchor points are:
-	int idx = 0;
-	for (int y = 0; y < a_SrcSizeY; y++)
+	// Pre-calculate the upscaling ratios:
+	TYPE RatioX[MAX_UPSCALE_X];
+	TYPE RatioY[MAX_UPSCALE_Y];
+	for (int x = 0; x <= a_UpscaleX; x++)
+	{
+		RatioX[x] = (TYPE)x / a_UpscaleX;
+	}
+	for (int y = 0; y <= a_UpscaleY; y++)
+	{
+		RatioY[y] = (TYPE)y / a_UpscaleY;
+	}
+	
+	// Interpolate each XY cell:
+	int DstSizeX = (a_SrcSizeX - 1) * a_UpscaleX + 1;
+	int DstSizeY = (a_SrcSizeY - 1) * a_UpscaleY + 1;
+	for (int y = 0; y < (a_SrcSizeY - 1); y++)
 	{
 		int DstY = y * a_UpscaleY;
-		for (int x = 0; x < a_SrcSizeX; x++)
+		int idx = y * a_SrcSizeX;
+		for (int x = 0; x < (a_SrcSizeX - 1); x++, idx++)
 		{
 			int DstX = x * a_UpscaleX;
-			TYPE StartValue = a_Src[idx];               // [x, y]
-			TYPE EndValue   = a_Src[idx + a_SrcSizeX];  // [x, y + 1]
-			TYPE Diff = EndValue - StartValue;
+			TYPE LoXLoY = a_Src[idx];
+			TYPE LoXHiY = a_Src[idx + a_SrcSizeX];
+			TYPE HiXLoY = a_Src[idx + 1];
+			TYPE HiXHiY = a_Src[idx + 1 + a_SrcSizeX];
 			for (int CellY = 0; CellY <= a_UpscaleY; CellY++)
 			{
-				a_Dst[DstX + (DstY + CellY) * a_SizeY] = StartValue + Diff * CellY / a_AnchorStepY;
+				int DestIdx = (DstY + CellY) * DstSizeX + DstX;
+				ASSERT(DestIdx + a_UpscaleX < DstSizeX * DstSizeY);
+				TYPE LoXInY = LoXLoY + (LoXHiY - LoXLoY) * RatioY[CellY];
+				TYPE HiXInY = HiXLoY + (HiXHiY - HiXLoY) * RatioY[CellY];
+				for (int CellX = 0; CellX <= a_UpscaleX; CellX++, DestIdx++)
+				{
+					a_Dst[DestIdx] = LoXInY + (HiXInY - LoXInY) * RatioX[CellX];
+				}
 			}  // for CellY
 		}  // for x
 	}  // for y
-	
-	// Now interpolate in rows (same-X), each row already has valid values in the anchor columns
-	int DstSizeY = a_SizeY * a_UpscaleY;
-	int DstSizeX = a_SizeX * a_UpscaleX;
-	for (int y = 0; y < DstSizeY; y++)
-	{
-		int Idx = y * DstSizeX;
-		for (int x = 0; x < a_SizeX; x++)
-		{
-			TYPE StartValue = a_Dst[Idx];               // [x,     y] in the src coords
-			TYPE EndValue   = a_Dst[Idx + a_UpscaleX];  // [x + 1, y] in the src coords
-			TYPE Diff = EndValue - StartValue;
-			for (int CellX = 0; CellX <= a_UpscaleX; CellX++)
-			{
-				a_Dst[Idx + CellX] = StartValue + CellX * Diff / a_UpscaleX;
-			}  // for CellY
-			Idx += a_UpscaleX;
-		}
-	}
 }
 
 
diff --git a/source/Noise.cpp b/source/Noise.cpp
index 87b3bd4a5..333dc8333 100644
--- a/source/Noise.cpp
+++ b/source/Noise.cpp
@@ -570,7 +570,7 @@ void cCubicNoise::Generate2D(
 			m_NumSingleY++;
 		}
 		m_NumCalls++;
-	#endif _DEBUG
+	#endif  // _DEBUG
 	
 	// Calculate query values using Cell:
 	int FromY = 0;