diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 998f49231..cad1fc30c 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,3 +1,8 @@
+August 12, 2006
+- Added support for truecolor PNG textures. They still get resampled to the
+  global palette, but at least they are visible now.
+- Optimized UnfilterRow() in m_png.cpp a little.
+
 August 11, 2006 (Changes by Graf Zahl)
 - Fixed: P_CheckOnMobjZ returned the first thing an actor could stand on, 
   not the highest possible.
diff --git a/src/m_png.cpp b/src/m_png.cpp
index b3eaf48a2..38e56ee5e 100644
--- a/src/m_png.cpp
+++ b/src/m_png.cpp
@@ -99,7 +99,7 @@ static inline void MakeChunk (void *where, DWORD type, size_t len);
 static inline void StuffPalette (const PalEntry *from, BYTE *to);
 static bool StuffBitmap (const DCanvas *canvas, FILE *file);
 static bool WriteIDAT (FILE *file, const BYTE *data, int len);
-static void UnfilterRow (int width, BYTE *dest, BYTE *stream, BYTE *prev);
+static void UnfilterRow (int width, BYTE *dest, BYTE *stream, BYTE *prev, int bpp);
 static void UnpackPixels (int width, int bytesPerRow, int bitdepth, BYTE *row);
 
 // EXTERNAL DATA DECLARATIONS ----------------------------------------------
@@ -532,17 +532,30 @@ bool M_ReadIDAT (FileReader *file, BYTE *buffer, int width, int height, int pitc
 	int y;
 	bool lastIDAT;
 	int bytesPerRowIn;
+	int bytesPerPixel;
 
-	inputLine = (Byte *)alloca (1+width*2);
-	prev = inputLine + 1 + width;
-	memset (prev, 0, width);
+	switch (colortype)
+	{
+	case 2:		bytesPerPixel = 3;		break;		// RGB
+	case 4:		bytesPerPixel = 2;		break;		// LA
+	case 6:		bytesPerPixel = 4;		break;		// RGBA
+	default:	bytesPerPixel = 1;		break;
+	}
+	inputLine = (Byte *)alloca (1 + width*bytesPerPixel*2);
+	prev = inputLine + 1 + width*bytesPerPixel;
+	memset (prev, 0, width*bytesPerPixel);
+
+	if (bytesPerPixel == 1 && bitdepth != 8)
+	{ // This is an invalid combination for PNG files
+		return false;
+	}
 
 	switch (bitdepth)
 	{
-	case 8:		bytesPerRowIn = width;			break;
-	case 4:		bytesPerRowIn = (width+1)/2;	break;
-	case 2:		bytesPerRowIn = (width+3)/4;	break;
-	case 1:		bytesPerRowIn = (width+7)/8;	break;
+	case 8:		bytesPerRowIn = width * bytesPerPixel;	break;
+	case 4:		bytesPerRowIn = (width+1)/2;			break;
+	case 2:		bytesPerRowIn = (width+3)/4;			break;
+	case 1:		bytesPerRowIn = (width+7)/8;			break;
 	default:	return false;
 	}
 
@@ -581,7 +594,7 @@ bool M_ReadIDAT (FileReader *file, BYTE *buffer, int width, int height, int pitc
 
 			if (stream.avail_out == 0)
 			{
-				UnfilterRow (bytesPerRowIn, curr, inputLine, prev);
+				UnfilterRow (bytesPerRowIn, curr, inputLine, prev, bytesPerPixel);
 				prev = curr;
 				curr += pitch;
 				y++;
@@ -800,51 +813,77 @@ static bool WriteIDAT (FILE *file, const BYTE *data, int len)
 // UnfilterRow
 //
 // Unfilters the given row. Unknown filter types are silently ignored.
+// bpp is bytes per pixel, not bits per pixel.
+// width is in bytes, not pixels.
 //
 //==========================================================================
 
-void UnfilterRow (int width, BYTE *dest, BYTE *row, BYTE *prev)
+void UnfilterRow (int width, BYTE *dest, BYTE *row, BYTE *prev, int bpp)
 {
 	int x;
 
 	switch (*row++)
 	{
 	case 1:		// Sub
-		dest[0] = row[0];
-		for (x = 1; x < width; ++x)
+		x = bpp;
+		do
 		{
-			dest[x] = row[x] + dest[x-1];
+			*dest++ = *row++;
+		}
+		while (--x);
+		for (x = width - bpp; x > 0; --x)
+		{
+			*dest = *row++ + *(dest - bpp);
+			dest++;
 		}
 		break;
 
 	case 2:		// Up
-		for (x = 0; x < width; ++x)
+		x = width;
+		do
 		{
-			dest[x] = row[x] + prev[x];
+			*dest++ = *row++ + *prev++;
 		}
+		while (--x);
 		break;
 
 	case 3:		// Average
-		dest[0] = row[0] + prev[0]/2;
-		for (x = 1; x < width; ++x)
+		x = bpp;
+		do
 		{
-			dest[x] = row[x] + (BYTE)(((unsigned)dest[x-1] + (unsigned)prev[x])/2);
+			*dest++ = *row++ + (*prev++)/2;
+		}
+		while (--x);
+		for (x = width - bpp; x > 0; --x)
+		{
+			*dest = *row++ + (BYTE)((unsigned(*(dest - bpp)) + unsigned(*prev++)) >> 1);
+			dest++;
 		}
 		break;
 
 	case 4:		// Paeth
-		dest[0] = row[0] + prev[0];
-		for (x = 1; x < width; ++x)
+		x = bpp;
+		do
+		{
+			*dest++ = *row++ + *prev++;
+		}
+		while (--x);
+		for (x = width - bpp; x > 0; --x)
 		{
 			int a, b, c, pa, pb, pc;
 
-			a = dest[x-1];
-			b = prev[x];
-			c = prev[x-1];
-			pa = abs (b - c);
-			pb = abs (a - c);
-			pc = abs (a + b - c - c);
-			dest[x] = row[x] + (BYTE)((pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c);
+			a = *(dest - bpp);
+			b = *(prev);
+			c = *(prev - bpp);
+			pa = b - c;
+			pb = a - c;
+			pc = abs (pa + pb);
+			pa = abs (pa);
+			pb = abs (pb);
+			*dest = *row + (BYTE)((pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c);
+			dest++;
+			row++;
+			prev++;
 		}
 		break;
 
diff --git a/src/r_data.cpp b/src/r_data.cpp
index ffb945b22..3fc4628c6 100644
--- a/src/r_data.cpp
+++ b/src/r_data.cpp
@@ -279,7 +279,11 @@ int FTextureManager::CreateTexture (int lumpnum, int usetype)
 			{
 				return -1;
 			}
-			if (colortype != 0 && colortype != 3)
+			if (!((1 << colortype) & 0x5D))
+			{
+				return -1;
+			}
+			if (!((1 << bitdepth) & 0x116))
 			{
 				return -1;
 			}
@@ -1853,21 +1857,13 @@ FPNGTexture::FPNGTexture (int lumpnum, int width, int height,
 	}
 	StartOfIDAT = lump.Tell() - 8;
 
-	if (colortype == 3)
-	{
-		PaletteMap = new BYTE[PaletteSize];
-		GPalette.MakeRemap (palette, PaletteMap, trans, PaletteSize);
-		for (i = 0; i < PaletteSize; ++i)
-		{
-			if (trans[i] == 0)
-			{
-				bMasked = true;
-				PaletteMap[i] = 0;
-			}
-		}
-	}
-	else if (colortype == 0)
+	switch (colortype)
 	{
+	case 4:		// Grayscale + Alpha
+		bMasked = true;
+		// intentional fall-through
+
+	case 0:		// Grayscale
 		if (!bAlphaTexture)
 		{
 			if (GrayMap[0] == GrayMap[255])
@@ -1877,7 +1873,7 @@ FPNGTexture::FPNGTexture (int lumpnum, int width, int height,
 					GrayMap[i] = ColorMatcher.Pick (i, i, i);
 				}
 			}
-			if (havetRNS && trans[0] != 0)
+			if (colortype == 0 && havetRNS && trans[0] != 0)
 			{
 				bMasked = true;
 				PaletteSize = 256;
@@ -1890,6 +1886,24 @@ FPNGTexture::FPNGTexture (int lumpnum, int width, int height,
 				PaletteMap = GrayMap;
 			}
 		}
+		break;
+
+	case 3:		// Paletted
+		PaletteMap = new BYTE[PaletteSize];
+		GPalette.MakeRemap (palette, PaletteMap, trans, PaletteSize);
+		for (i = 0; i < PaletteSize; ++i)
+		{
+			if (trans[i] == 0)
+			{
+				bMasked = true;
+				PaletteMap[i] = 0;
+			}
+		}
+		break;
+
+	case 6:		// RGB + Alpha
+		bMasked = true;
+		break;
 	}
 }
 
@@ -1964,33 +1978,111 @@ void FPNGTexture::MakeTexture ()
 		DWORD len, id;
 		lump.Seek (StartOfIDAT, SEEK_SET);
 		lump >> len >> id;
-		M_ReadIDAT (&lump, Pixels, Width, Height, Width, BitDepth, ColorType, Interlace, BigLong((unsigned int)len));
 
-		if (Width == Height)
+		if (ColorType == 0 || ColorType == 3)	/* Grayscale and paletted */
 		{
-			if (PaletteMap != NULL)
+			M_ReadIDAT (&lump, Pixels, Width, Height, Width, BitDepth, ColorType, Interlace, BigLong((unsigned int)len));
+
+			if (Width == Height)
 			{
-				FlipSquareBlockRemap (Pixels, Width, Height, PaletteMap);
+				if (PaletteMap != NULL)
+				{
+					FlipSquareBlockRemap (Pixels, Width, Height, PaletteMap);
+				}
+				else
+				{
+					FlipSquareBlock (Pixels, Width, Height);
+				}
 			}
 			else
 			{
-				FlipSquareBlock (Pixels, Width, Height);
+				BYTE *newpix = new BYTE[Width*Height];
+				if (PaletteMap != NULL)
+				{
+					FlipNonSquareBlockRemap (newpix, Pixels, Width, Height, PaletteMap);
+				}
+				else
+				{
+					FlipNonSquareBlock (newpix, Pixels, Width, Height, Width);
+				}
+				BYTE *oldpix = Pixels;
+				Pixels = newpix;
+				delete[] oldpix;
 			}
 		}
-		else
+		else		/* RGB and/or Alpha present */
 		{
-			BYTE *newpix = new BYTE[Width*Height];
-			if (PaletteMap != NULL)
+			int bytesPerPixel = ColorType == 2 ? 3 : ColorType == 4 ? 2 : 4;
+			BYTE *tempix = new BYTE[Width * Height * bytesPerPixel];
+			BYTE *in, *out;
+			int x, y, pitch, backstep;
+
+			M_ReadIDAT (&lump, tempix, Width, Height, Width*bytesPerPixel, BitDepth, ColorType, Interlace, BigLong((unsigned int)len));
+			in = tempix;
+			out = Pixels;
+
+			// Convert from source format to paletted, column-major.
+			// Formats with alpha maps are reduced to only 1 bit of alpha.
+			switch (ColorType)
 			{
-				FlipNonSquareBlockRemap (newpix, Pixels, Width, Height, PaletteMap);
+			case 2:		// RGB
+				pitch = Width * 3;
+				backstep = Height * pitch - 3;
+				for (x = Width; x > 0; --x)
+				{
+					for (y = Height; y > 0; --y)
+					{
+						*out++ = RGB32k[in[0]>>3][in[1]>>3][in[2]>>3];
+						in += pitch;
+					}
+					in -= backstep;
+				}
+				break;
+
+			case 4:		// Grayscale + Alpha
+				pitch = Width * 2;
+				backstep = Height * pitch - 2;
+				if (PaletteMap != NULL)
+				{
+					for (x = Width; x > 0; --x)
+					{
+						for (y = Height; y > 0; --y)
+						{
+							*out++ = in[1] < 128 ? 0 : PaletteMap[in[0]];
+							in += pitch;
+						}
+						in -= backstep;
+					}
+				}
+				else
+				{
+					for (x = Width; x > 0; --x)
+					{
+						for (y = Height; y > 0; --y)
+						{
+							*out++ = in[1] < 128 ? 0 : in[0];
+							in += pitch;
+						}
+						in -= backstep;
+					}
+				}
+				break;
+
+			case 6:		// RGB + Alpha
+				pitch = Width * 4;
+				backstep = Height * pitch - 4;
+				for (x = Width; x > 0; --x)
+				{
+					for (y = Height; y > 0; --y)
+					{
+						*out++ = in[3] < 128 ? 0 : RGB32k[in[0]>>3][in[1]>>3][in[2]>>3];
+						in += pitch;
+					}
+					in -= backstep;
+				}
+				break;
 			}
-			else
-			{
-				FlipNonSquareBlock (newpix, Pixels, Width, Height, Width);
-			}
-			BYTE *oldpix = Pixels;
-			Pixels = newpix;
-			delete[] oldpix;
+			delete[] tempix;
 		}
 	}
 	if (Spans == NULL)