From b9892a853bc82b79e3838b147d94b1f7b3a4a3cf Mon Sep 17 00:00:00 2001
From: Aerik72 <dummy@github.com>
Date: Sat, 7 Aug 2021 20:39:34 -0500
Subject: [PATCH 1/5] tr1pc_replace_textile function set up

---
 Source/tr1pc.c | 34 +++++++++++++++++++++++++++++++---
 Source/tr1pc.h |  5 ++++-
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/Source/tr1pc.c b/Source/tr1pc.c
index d7871ee..d35770f 100644
--- a/Source/tr1pc.c
+++ b/Source/tr1pc.c
@@ -250,6 +250,14 @@ void tr1pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	if (!_strnicmp(args[2],"get",3)&&!_strnicmp(args[3],"offset",6)) tr1pc_get_offset(bytelist, args, argc, p_NumVertices, p_NumSprites, p_NumLights, p_NumZSector, p_NumStaticMeshes, p_AlternateRoom, p_NumFloorData, p_NumItems, p_NumSpriteSequences, p_NumCameras, p_NumDemoData, p_NumBoxes, p_NumOverlaps, p_NumSoundDetails, p_NumSamples, p_NumSampleIndices, p_NumSoundSources, fsize);
 	if (!_strnicmp(args[2],"extract",7)&&!strnicmp(args[3],"textile",7)) tr1pc_extract_textile(bytelist, args, numTexTiles, p_TexTiles, palette, !strnicmp(args[4],"all",3) ? -1 : atoi(args[4]));
 
+	if (!_strnicmp(args[2], "replace", 7))
+	{
+		if (!strnicmp(args[3], "textile", 7))
+		{
+			tr1pc_replace_textile(bytelist, args, numTexTiles, p_TexTiles, palette);
+		}
+	}
+
 	free(p_TexTiles);
 	free(roomX);
 	free(roomY);
@@ -3152,8 +3160,9 @@ void tr1pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_Nu
 	if (!_strnicmp(args[4],"numsampleindices",16)) printf("%X\n",p_NumSampleIndices);
 }
 
+// This function extracts a texture tile from the level into a bitmap file. The syntax is "trmod [FILE] EXTRACT TEXTILE [#/All]".
 // int selection // -1 for all, 0 - (numTexTiles-1) for an individual texture tile
-void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, unsigned char* palette, int selection)
+void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette, int selection)
 {
 	if (selection < -1 || selection >= (int)numTexTiles)
 	{
@@ -3162,7 +3171,6 @@ void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 	}
 
 	printf("Extracting textile %d...\n", selection);
-	// This function extracts a texture tile from the level into a bitmap file. The syntax is "trmod [FILE] EXTRACT TEXTILE [#/All]".
 
 	printf("Writing \"palette.bmp\"...\n");
 	writeBitmap(palette, "palette.bmp", 16, 16);
@@ -3170,7 +3178,7 @@ void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 	const unsigned w = 256;
 	const unsigned h = 256;
 
-	for (int t = (selection == -1 ? 0 : selection); t <= (selection == -1 ? numTexTiles-1 : selection); ++t)
+	for (int t = (selection == -1 ? 0 : selection); t <= (selection == -1 ? numTexTiles - 1 : selection); ++t)
 	{
 		unsigned char* img = (char*)malloc(3 * w * h);
 		memset(img, 0, 3 * w * h); // Fill the whole image with 0s
@@ -3215,4 +3223,24 @@ void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 		free(img);
 		free(filename);
 	}
+}
+
+// This function replaces a texture tile in the level from a bitmap file. The syntax is "trmod [FILE] REPLACE TEXTILE [#] [FILENAME.BMP]".
+void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE * palette)
+{
+	int selection = atoi(args[4]);
+	char* filename = args[5];
+
+	if (selection < 0 || selection >= (int)numTexTiles)
+	{
+		printf("ERROR: Textile selection must be between \"0\" and \"%d\", argument was \"%d\"", numTexTiles - 1, selection);
+		return 0;
+	}
+
+	printf("Replacing textile %d...\n", selection);
+
+	const unsigned w = 256;
+	const unsigned h = 256;
+
+	// todo
 }
\ No newline at end of file
diff --git a/Source/tr1pc.h b/Source/tr1pc.h
index fde23aa..b131adc 100644
--- a/Source/tr1pc.h
+++ b/Source/tr1pc.h
@@ -1,6 +1,8 @@
 #ifndef TR1PC_H_INCLUDED
 #define TR1PC_H_INCLUDED
 
+typedef unsigned char BYTE;
+
 void tr1pc_main(int argc, char *args[], char *bytelist, unsigned fsize);
 void tr1pc_list(char *bytelist, char *args[], unsigned roomX[], int roomY[], unsigned roomZ[], unsigned p_NumVertices[], unsigned p_NumSprites[], unsigned p_NumLights[], unsigned p_NumZSector[], unsigned p_NumStaticMeshes[], unsigned p_AlternateRoom[], unsigned p_NumFloorData, unsigned p_NumSpriteSequences, unsigned p_NumCameras, unsigned p_NumBoxes, unsigned p_NumSoundSources, unsigned p_NumItems, unsigned short numRooms, unsigned fsize);
 void tr1pc_add_item(char *bytelist, char *args[], unsigned roomX[], int roomY[], unsigned roomZ[], unsigned p_NumItems, unsigned fsize);
@@ -59,6 +61,7 @@ void tr1pc_replace_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsig
 void tr1pc_add_overlap(char *bytelist, char *args[], unsigned argc, unsigned p_NumOverlaps, unsigned fsize);
 void tr1pc_overwrite_overlap(char *bytelist, char *args[], unsigned argc, unsigned p_NumOverlaps, unsigned fsize);
 void tr1pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_NumVertices[], unsigned p_NumSprites[], unsigned p_NumLights[], unsigned p_NumZSector[], unsigned p_NumStaticMeshes[], unsigned p_AlternateRoom[], unsigned p_NumFloorData, unsigned p_NumItems, unsigned p_NumSpriteSequences, unsigned p_NumCameras, unsigned p_NumDemoData, unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned p_NumSoundDetails, unsigned p_NumSamples, unsigned p_NumSampleIndices, unsigned p_NumSoundSources, unsigned fsize);
-void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, unsigned char* palette, int selection);
+void tr1pc_extract_textile(char *bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette, int selection);
+void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette);
 
 #endif

From 6e7f7b3d1ba5e9c89c5b9ab6dbf2d1b663a51f61 Mon Sep 17 00:00:00 2001
From: Aerik72 <dummy@github.com>
Date: Sun, 8 Aug 2021 16:34:06 -0500
Subject: [PATCH 2/5] TR1PC replace textile working

---
 Source/functions.c | 135 +++++++++++++++++++++++++++++++++++++++++++++
 Source/functions.h |   4 ++
 Source/tr1pc.c     |  52 ++++++++++++++---
 Source/tr1pc.h     |   2 +-
 4 files changed, 185 insertions(+), 8 deletions(-)

diff --git a/Source/functions.c b/Source/functions.c
index e6723d6..04f7e91 100644
--- a/Source/functions.c
+++ b/Source/functions.c
@@ -2,6 +2,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include "functions.h"
+
 char* readFile(char *inputFile){
 	// This function reads a file into memory, and returns a pointer
 	printf("Reading binary file %s...\n", inputFile);
@@ -22,6 +24,86 @@ char* readFile(char *inputFile){
 	fclose(levelFile); // Closes file
 	return bytelist;
 }
+
+// This function requires a 24-bit bitmap with no compression
+// The caller of the function is responsible for freeing the returned BYTE* memory
+// Returns the pixel array in 3-byte RGB pixels, with rows bottom-to-top
+BYTE* readBitmapFile(char* inputFilename)
+{
+	char* image = readFile(inputFilename);
+
+	// Check bitmap integrity
+	BYTE bmpIntegrityA;
+	BYTE bmpIntegrityB;
+	memcpy(&bmpIntegrityA, image + 0, 1);
+	memcpy(&bmpIntegrityB, image + 1, 1);
+	//printf("Bitmap integrity: %c%c\n", bmpIntegrityA, bmpIntegrityB);
+	if (!(bmpIntegrityA == 'B' && bmpIntegrityB == 'M'))
+	{
+		printf("ERROR: File must be BM for Windows 3.1x, 95, NT, etc.\n");
+		free(image);
+		return NULL;
+	}
+
+	// Verify that the bitmap is 24 bits per pixel
+	unsigned short bitsPerPixel;
+	memcpy(&bitsPerPixel, image + 28, 2);
+	//printf("Bitmap bpp: %d", bitsPerPixel);
+	if (!bitsPerPixel == 24)
+	{
+		printf("ERROR: Bitmap must be 24 bits per pixel.\n");
+		free(image);
+		return NULL;
+	}
+
+	// Verify image is uncompressed
+	signed int compression;
+	memcpy(&compression, image + 30, 4);
+	//printf("Compression method: %d", compression);
+	if (compression != 0)
+	{
+		printf("ERROR: Bitmap must be uncompressed (found compression method %d, must be 0 a.k.a. BI_RGB).\n", compression);
+		free(image);
+		return NULL;
+	}
+
+	// Read width and height
+	signed int width;
+	signed int height;
+	memcpy(&width, image + 18, 4);
+	memcpy(&height, image + 22, 4);
+	//printf("Width x height: %d x %d\n", width, height);
+
+	// Read image size
+	signed int imageSize;
+	memcpy(&imageSize, image + 34, 4);
+	if (imageSize == 0)
+	{
+		// For BI_RGB, a dummy 0 may indicate bpp x w x h
+		imageSize = bitsPerPixel * width * height;
+	}
+	printf("Image size: %d\n", imageSize);
+
+	// Allocate memory for result
+	BYTE* result = malloc(imageSize * sizeof(BYTE));
+	if (result == 0)
+	{
+		printf("ERROR: Could not allocate memory to read bmp! (error code: %d)\n", errno);
+		return NULL;
+	}
+
+	// Determine the offset of the pixel array
+	signed int offset;
+	memcpy(&offset, image + 10, 4);
+	//printf("Bitmap pixel array offset: %d", offset);
+
+	memcpy(result, image + offset, imageSize);
+
+	free(image);
+
+	return result;
+}
+
 void writeFile(char *outputFile, char *bytelist, unsigned fsize){
 	// This function writes bytelist to the level file.
 	FILE *File = fopen(outputFile,"wb");
@@ -118,3 +200,56 @@ void writeBitmap(char* img, char* filename, const unsigned w, const unsigned h)
 
 	fclose(f);
 }
+
+BYTE findPixelKey(BYTE* palette, BYTE r, BYTE g, BYTE b)
+{
+	BYTE pr, pg, pb;
+	BYTE result;
+	short closestMatch = 255 * 3;
+	short diff;
+	BYTE isExactMatch = 0;
+	BYTE rpr, rpg, rpb;
+	for (int i = 0; i < 256; i++)
+	{
+		short curpos = i * 3;
+		memcpy(&pr, palette + curpos + 2, 1);
+		memcpy(&pg, palette + curpos + 1, 1);
+		memcpy(&pb, palette + curpos + 0, 1);
+
+		if (pr == r &&
+			pg == g &&
+			pb == b)
+		{
+			result = i;
+			isExactMatch = 1;
+			break;
+		}
+
+		diff = abs(pr - r) +
+			   abs(pg - g) +
+			   abs(pb - b);
+
+		if (diff < closestMatch)
+		{
+			closestMatch = diff;
+			result = i;
+			rpr = pr;
+			rpg = pg;
+			rpb = pb;
+			isExactMatch = 0;
+		}
+	}
+
+	/*
+	if (isExactMatch == 1)
+	{
+		printf("Exact match: %d, %d, %d matches palette %d\n", r, g, b, result);
+	}
+	else
+	{
+		printf("No match: %d, %d, %d is closest to palette %d (%d, %d, %d)\n", r, g, b, result, rpr, rpg, rpb);
+	}
+	*/
+
+	return result;
+}
diff --git a/Source/functions.h b/Source/functions.h
index ca2f3ac..871e932 100644
--- a/Source/functions.h
+++ b/Source/functions.h
@@ -1,7 +1,10 @@
 #ifndef FUNCTIONS_H_INCLUDED
 #define FUNCTIONS_H_INCLUDED
 
+typedef unsigned char BYTE;
+
 char* readFile(char *inputFile);
+BYTE* readBitmapFile(char* inputFilename);
 void writeFile(char *outputFile, char *bytelist, unsigned fsize);
 unsigned filesize(char *inputFile);
 char* substring(char *string, unsigned offset, unsigned length);
@@ -10,5 +13,6 @@ unsigned countchar(char *instring, char countChar);
 char* insertrange(char *bytelist, unsigned offset, unsigned length, char *insertme, unsigned fsize);
 unsigned removerange(char *bytelist, unsigned offset, unsigned length, unsigned fsize);
 void writeBitmap(char* img, char* filename, const unsigned w, const unsigned h);
+BYTE findPixelKey(BYTE* palette, BYTE r, BYTE g, BYTE b);
 
 #endif
\ No newline at end of file
diff --git a/Source/tr1pc.c b/Source/tr1pc.c
index d35770f..b6d8a71 100644
--- a/Source/tr1pc.c
+++ b/Source/tr1pc.c
@@ -254,7 +254,7 @@ void tr1pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	{
 		if (!strnicmp(args[3], "textile", 7))
 		{
-			tr1pc_replace_textile(bytelist, args, numTexTiles, p_TexTiles, palette);
+			tr1pc_replace_textile(bytelist, args, numTexTiles, p_TexTiles, palette, fsize);
 		}
 	}
 
@@ -3226,12 +3226,12 @@ void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 }
 
 // This function replaces a texture tile in the level from a bitmap file. The syntax is "trmod [FILE] REPLACE TEXTILE [#] [FILENAME.BMP]".
-void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE * palette)
+void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE * palette, unsigned fsize)
 {
-	int selection = atoi(args[4]);
+	unsigned int selection = atoi(args[4]);
 	char* filename = args[5];
 
-	if (selection < 0 || selection >= (int)numTexTiles)
+	if (selection < 0 || selection >= numTexTiles)
 	{
 		printf("ERROR: Textile selection must be between \"0\" and \"%d\", argument was \"%d\"", numTexTiles - 1, selection);
 		return 0;
@@ -3239,8 +3239,46 @@ void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 
 	printf("Replacing textile %d...\n", selection);
 
-	const unsigned w = 256;
-	const unsigned h = 256;
+	const short w = 256;
+	const short h = 256;
+	unsigned memorySize = 3 * w * h;
+
+	BYTE* bitmapImage = readBitmapFile(filename);
+	if (bitmapImage == NULL)
+	{
+		printf("ERROR: Could not read bitmap.\n");
+		return 0;
+	}
+
+	for (int j = 0; j < h; j++)
+	{
+		for (int i = 0; i < w; i++)
+		{
+			unsigned int curpos = j * w + i;
+			BYTE r;
+			BYTE g;
+			BYTE b;
+			BYTE pixelKey;
+
+			memcpy(&r, bitmapImage + curpos * 3 + 2, 1);
+			memcpy(&g, bitmapImage + curpos * 3 + 1, 1);
+			memcpy(&b, bitmapImage + curpos * 3 + 0, 1);
+
+			if (r == 0 && g == 0 && b == 0)
+			{
+				pixelKey = 0; // Reserved for pure-black aka transparent
+			}
+			else
+			{
+				pixelKey = findPixelKey(palette, r, g, b);
+			}
+
+			unsigned int curposFlip = ((h - 1 - j) * w) + i; // Bitmap rows are stored bottom-up
+			memcpy(bytelist + p_TexTiles[selection] + curposFlip, &pixelKey, 1);
+		}
+	}
+
+	writeFile(args[1], bytelist, fsize);
 
-	// todo
+	free(bitmapImage);
 }
\ No newline at end of file
diff --git a/Source/tr1pc.h b/Source/tr1pc.h
index b131adc..fe761a1 100644
--- a/Source/tr1pc.h
+++ b/Source/tr1pc.h
@@ -62,6 +62,6 @@ void tr1pc_add_overlap(char *bytelist, char *args[], unsigned argc, unsigned p_N
 void tr1pc_overwrite_overlap(char *bytelist, char *args[], unsigned argc, unsigned p_NumOverlaps, unsigned fsize);
 void tr1pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_NumVertices[], unsigned p_NumSprites[], unsigned p_NumLights[], unsigned p_NumZSector[], unsigned p_NumStaticMeshes[], unsigned p_AlternateRoom[], unsigned p_NumFloorData, unsigned p_NumItems, unsigned p_NumSpriteSequences, unsigned p_NumCameras, unsigned p_NumDemoData, unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned p_NumSoundDetails, unsigned p_NumSamples, unsigned p_NumSampleIndices, unsigned p_NumSoundSources, unsigned fsize);
 void tr1pc_extract_textile(char *bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette, int selection);
-void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette);
+void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette, unsigned fsize);
 
 #endif

From 5e0507b64af90c15613a5eee9439386e62ad9cf3 Mon Sep 17 00:00:00 2001
From: Aerik72 <dummy@github.com>
Date: Mon, 9 Aug 2021 22:55:49 -0500
Subject: [PATCH 3/5] TR2PC replace textile working

---
 Source/tr1pc.c |  2 +-
 Source/tr2pc.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++
 Source/tr2pc.h |  1 +
 3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/Source/tr1pc.c b/Source/tr1pc.c
index b6d8a71..8f42d89 100644
--- a/Source/tr1pc.c
+++ b/Source/tr1pc.c
@@ -3180,7 +3180,7 @@ void tr1pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 
 	for (int t = (selection == -1 ? 0 : selection); t <= (selection == -1 ? numTexTiles - 1 : selection); ++t)
 	{
-		unsigned char* img = (char*)malloc(3 * w * h);
+		BYTE* img = malloc(3 * w * h);
 		memset(img, 0, 3 * w * h); // Fill the whole image with 0s
 
 		for (int j = 0; j < h; j++)
diff --git a/Source/tr2pc.c b/Source/tr2pc.c
index 8b54515..43588e4 100644
--- a/Source/tr2pc.c
+++ b/Source/tr2pc.c
@@ -250,6 +250,14 @@ void tr2pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	if (!_strnicmp(args[2],"get",3)&&!_strnicmp(args[3],"offset",6)) tr2pc_get_offset(bytelist, args, argc, p_NumVertices, p_NumSprites, p_NumLights, p_NumZSector, p_NumStaticMeshes, p_AlternateRoom, p_NumFloorData, p_NumItems, p_NumSpriteSequences, p_NumCameras, p_NumDemoData, p_NumBoxes, p_NumOverlaps, p_NumSoundSources, fsize);
 	if (!_strnicmp(args[2], "extract", 7) && !strnicmp(args[3], "textile", 7)) tr2pc_extract_textile(bytelist, args, numTexTiles, p_TexTiles8, palette8, !strnicmp(args[4], "all", 3) ? -1 : atoi(args[4]));
 
+	if (!_strnicmp(args[2], "replace", 7))
+	{
+		if (!strnicmp(args[3], "textile", 7))
+		{
+			tr2pc_replace_textile(bytelist, args, numTexTiles, p_TexTiles8, palette8, fsize);
+		}
+	}
+
 	free(palette8);
 	free(palette16);
 	free(p_TexTiles8);
@@ -2964,3 +2972,61 @@ void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 		free(filename);
 	}
 }
+
+// This function replaces a texture tile in the level from a bitmap file. The syntax is "trmod [FILE] REPLACE TEXTILE [#] [FILENAME.BMP]".
+void tr2pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize)
+{
+	unsigned int selection = atoi(args[4]);
+	char* filename = args[5];
+
+	if (selection < 0 || selection >= numTexTiles)
+	{
+		printf("ERROR: Textile selection must be between \"0\" and \"%d\", argument was \"%d\"", numTexTiles - 1, selection);
+		return 0;
+	}
+
+	printf("Replacing 8-bit textile %d...\n", selection);
+
+	const short w = 256;
+	const short h = 256;
+	unsigned memorySize = 3 * w * h;
+
+	BYTE* bitmapImage = readBitmapFile(filename);
+	if (bitmapImage == NULL)
+	{
+		printf("ERROR: Could not read bitmap.\n");
+		return 0;
+	}
+
+	for (int j = 0; j < h; j++)
+	{
+		for (int i = 0; i < w; i++)
+		{
+			unsigned int curpos = j * w + i;
+			BYTE r;
+			BYTE g;
+			BYTE b;
+			BYTE pixelKey;
+
+			memcpy(&r, bitmapImage + curpos * 3 + 2, 1);
+			memcpy(&g, bitmapImage + curpos * 3 + 1, 1);
+			memcpy(&b, bitmapImage + curpos * 3 + 0, 1);
+
+			if (r == 255 && g == 0 && b == 255)
+			{
+				pixelKey = 0; // Reserved for pure-magenta aka transparent
+			}
+			else
+			{
+				pixelKey = findPixelKey(palette8, r, g, b);
+			}
+
+			unsigned int curposFlip = ((h - 1 - j) * w) + i; // Bitmap rows are stored bottom-up
+			memcpy(bytelist + p_TexTiles[selection] + curposFlip, &pixelKey, 1);
+		}
+	}
+
+	writeFile(args[1], bytelist, fsize);
+
+	free(bitmapImage);
+}
diff --git a/Source/tr2pc.h b/Source/tr2pc.h
index 67bd27f..d15872a 100644
--- a/Source/tr2pc.h
+++ b/Source/tr2pc.h
@@ -40,5 +40,6 @@ void tr2pc_add_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned
 void tr2pc_replace_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned fsize);
 void tr2pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_NumVertices[], unsigned p_NumSprites[], unsigned p_NumLights[], unsigned p_NumZSector[], unsigned p_NumStaticMeshes[], unsigned p_AlternateRoom[], unsigned p_NumFloorData, unsigned p_NumItems, unsigned p_NumSpriteSequences, unsigned p_NumCameras, unsigned p_NumDemoData, unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned p_NumSoundSources, unsigned fsize);
 void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, int selection);
+void tr2pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize);
 
 #endif

From d48ccd3d9cf9b03e36f4c4e1c0183d3eadfbfc4a Mon Sep 17 00:00:00 2001
From: Aerik72 <dummy@github.com>
Date: Tue, 10 Aug 2021 23:11:10 -0500
Subject: [PATCH 4/5] TR2 textile extract working tentatively

---
 Source/functions.c |  36 ++++++++++++++
 Source/tr1psx.c    |   8 ++++
 Source/tr2pc.c     | 115 ++++++++++++++++++++++++++++++++++++++++++---
 Source/tr2pc.h     |   5 +-
 4 files changed, 155 insertions(+), 9 deletions(-)

diff --git a/Source/functions.c b/Source/functions.c
index 04f7e91..575d57e 100644
--- a/Source/functions.c
+++ b/Source/functions.c
@@ -166,6 +166,9 @@ unsigned removerange(char *bytelist, unsigned offset, unsigned length, unsigned
 	return (fsize-length);
 }
 
+// This function writes a 24-bit bitmap (R8 G8 B8)
+// In TR1, full black (0, 0, 0) represents transparent
+// In TR2, full magenta (255, 0, 255) represents transparent
 void writeBitmap(char* img, char* filename, const unsigned w, const unsigned h)
 {
 	FILE* f;
@@ -201,6 +204,39 @@ void writeBitmap(char* img, char* filename, const unsigned w, const unsigned h)
 	fclose(f);
 }
 
+void writeBitmap32(char* img, char* filename, const unsigned w, const unsigned h)
+{
+	FILE* f;
+	int bmpFileSize = 54 + 4 * w * h;
+
+	unsigned char bmpfileheader[14] = { 'B','M', 0,0,0,0, 0,0, 0,0, 54,0,0,0 };
+	unsigned char bmpinfoheader[40] = { 40,0,0,0, 0,0,0,0, 0,0,0,0, 1,0, 32,0 };
+
+	bmpfileheader[2] = (unsigned char)(bmpFileSize);
+	bmpfileheader[3] = (unsigned char)(bmpFileSize >> 8);
+	bmpfileheader[4] = (unsigned char)(bmpFileSize >> 16);
+	bmpfileheader[5] = (unsigned char)(bmpFileSize >> 24);
+
+	bmpinfoheader[4] = (unsigned char)(w);
+	bmpinfoheader[5] = (unsigned char)(w >> 8);
+	bmpinfoheader[6] = (unsigned char)(w >> 16);
+	bmpinfoheader[7] = (unsigned char)(w >> 24);
+	bmpinfoheader[8] = (unsigned char)(h);
+	bmpinfoheader[9] = (unsigned char)(h >> 8);
+	bmpinfoheader[10] = (unsigned char)(h >> 16);
+	bmpinfoheader[11] = (unsigned char)(h >> 24);
+
+	f = fopen(filename, "wb");
+	fwrite(bmpfileheader, 1, 14, f);
+	fwrite(bmpinfoheader, 1, 40, f);
+	for (int i = 0; i < h; i++)
+	{
+		fwrite(img + (w * (h - i - 1) * 4), 4, w, f);
+	}
+
+	fclose(f);
+}
+
 BYTE findPixelKey(BYTE* palette, BYTE r, BYTE g, BYTE b)
 {
 	BYTE pr, pg, pb;
diff --git a/Source/tr1psx.c b/Source/tr1psx.c
index 545020c..1c3d032 100644
--- a/Source/tr1psx.c
+++ b/Source/tr1psx.c
@@ -178,6 +178,14 @@ void tr1psx_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	if (!_strnicmp(args[2],"get",3)&&!_strnicmp(args[3],"offset",6)) tr1psx_get_offset(bytelist, args, argc, p_NumVertices, p_NumSprites, p_NumLights, p_NumZSector, p_NumStaticMeshes, p_AlternateRoom, p_NumFloorData, p_NumItems, p_NumSpriteSequences, p_NumCameras, p_NumBoxes, p_NumOverlaps, p_NumSoundSources, fsize);
 	if (!_strnicmp(args[2], "extract", 7) && !strnicmp(args[3], "textile", 7)) printf("EXTRACT TEXTILE is not supported for PSX file format.");
 
+	if (!_strnicmp(args[2], "replace", 7))
+	{
+		if (!strnicmp(args[3], "textile", 7))
+		{
+			printf("REPLACE TEXTILE is not supported for PSX file format.");
+		}
+	}
+
 	free(roomX);
 	free(roomY);
 	free(roomZ);
diff --git a/Source/tr2pc.c b/Source/tr2pc.c
index 43588e4..c20eac1 100644
--- a/Source/tr2pc.c
+++ b/Source/tr2pc.c
@@ -49,6 +49,7 @@ void tr2pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	// 16-bit palette
 	// NOTE: There is no reason for us to store the unused byte, so we'll discard it for a smaller memory footprint.
 	// tr_colour4 Palette16[256]; // 16-bit palette (1024 bytes)
+	// The 16-bit palette is used for identifying the colors of solid polygons, *not* textile colors.
 	// struct tr_colour4  // 4 bytes
 	// {
 	//		uint8_t Red;
@@ -69,18 +70,23 @@ void tr2pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 
 	// Texture tiles
 	// uint32_t NumTextiles; // number of texture tiles (4 bytes)
-	// tr2_textile8 Textile8[NumTextiles]; // 8-bit (palettized) textiles (NumTextiles * 65536 bytes)
-	// tr2_textile16 Textile16[NumTextiles]; // 16-bit (ARGB) textiles (NumTextiles * 131072 bytes)
 	memcpy(&freeuint1, bytelist + curpos, 4); // Number of Texture Tiles
 	numTexTiles = freeuint1;
 	curpos += 4;
 
+	// tr2_textile8 Textile8[NumTextiles]; // 8-bit (palettized) textiles (NumTextiles * 65536 bytes)
 	p_TexTiles8 = malloc(numTexTiles * sizeof(unsigned)); // Offsets of 8-bit TexTiles
 	for (int i = 0; i < numTexTiles; i++)
 	{
 		p_TexTiles8[i] = curpos;
 		curpos += (1 << 16); // Each texture is 8 bits in a 256 x 256 grid a.k.a. 2^16
 	}
+
+	// tr2_textile16 Textile16[NumTextiles]; // 16-bit (ARGB) textiles (NumTextiles * 131072 bytes)
+	// The 16-bit textile array, which contains[tr_textile16] structures, specifies colours using 16 - bit ARGB,
+	// where the highest bit (0x8000) is a crude alpha channel (really just a simple transparency: 0==transparent, 1==opaque).
+	// The next 5 bits(0x7C00) specify the red channel, the next 5 bits(0x03E0) specify the green channel,
+	// and the last 5 bits(0x001F) specify the blue channel, each on a scale from 0..31.
 	p_TexTiles16 = malloc(numTexTiles * sizeof(unsigned)); // Offsets of 16-bit TexTiles
 	for (int i = 0; i < numTexTiles; i++)
 	{
@@ -248,13 +254,26 @@ void tr2pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	if (!_strnicmp(args[2],"add",3)&&!_strnicmp(args[3],"overlap",7)) tr1pc_add_overlap(bytelist, args, argc, p_NumOverlaps, fsize);
 	if (!_strnicmp(args[2],"overwrite",7)&&!_strnicmp(args[3],"overlap",7)) tr1pc_overwrite_overlap(bytelist, args, argc, p_NumOverlaps, fsize);
 	if (!_strnicmp(args[2],"get",3)&&!_strnicmp(args[3],"offset",6)) tr2pc_get_offset(bytelist, args, argc, p_NumVertices, p_NumSprites, p_NumLights, p_NumZSector, p_NumStaticMeshes, p_AlternateRoom, p_NumFloorData, p_NumItems, p_NumSpriteSequences, p_NumCameras, p_NumDemoData, p_NumBoxes, p_NumOverlaps, p_NumSoundSources, fsize);
-	if (!_strnicmp(args[2], "extract", 7) && !strnicmp(args[3], "textile", 7)) tr2pc_extract_textile(bytelist, args, numTexTiles, p_TexTiles8, palette8, !strnicmp(args[4], "all", 3) ? -1 : atoi(args[4]));
+
+	if (!_strnicmp(args[2], "extract", 7))
+	{
+		if (!strnicmp(args[3], "textile", 9))
+		{
+			tr2pc_extract_textile16(bytelist, args, numTexTiles, p_TexTiles16, !strnicmp(args[4], "all", 3) ? -1 : atoi(args[4]));
+		}
+		else if (!strnicmp(args[3], "textile8", 7))
+		{
+			printf("WARNING: 8-bit textures are a legacy feature, and will probably not render on a modern PC.\n");
+			tr2pc_extract_textile8(bytelist, args, numTexTiles, p_TexTiles8, palette8, !strnicmp(args[4], "all", 3) ? -1 : atoi(args[4]));
+		}
+	}
 
 	if (!_strnicmp(args[2], "replace", 7))
 	{
-		if (!strnicmp(args[3], "textile", 7))
+		if (!strnicmp(args[3], "textile8", 7))
 		{
-			tr2pc_replace_textile(bytelist, args, numTexTiles, p_TexTiles8, palette8, fsize);
+			printf("WARNING: 8-bit textures are a legacy feature, and will probably not render on a modern PC.\n");
+			tr2pc_replace_textile8(bytelist, args, numTexTiles, p_TexTiles8, palette8, fsize);
 		}
 	}
 
@@ -2909,7 +2928,7 @@ void tr2pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_Nu
 }
 
 // int selection // -1 for all, 0 - (numTexTiles-1) for an individual texture tile
-void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles8, BYTE* palette8, int selection)
+void tr2pc_extract_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles8, BYTE* palette8, int selection)
 {
 	if (selection < -1 || selection >= (int)numTexTiles)
 	{
@@ -2973,8 +2992,90 @@ void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 	}
 }
 
+// tr2_textile16 Textile16[NumTextiles]; // 16-bit (ARGB) textiles (NumTextiles * 131072 bytes)
+// The 16-bit textile array, which contains[tr_textile16] structures, specifies colours using 16 - bit ARGB,
+// where the highest bit (0x8000) is a crude alpha channel (really just a simple transparency: 0==transparent, 1==opaque).
+// The next 5 bits(0x7C00) specify the red channel, the next 5 bits(0x03E0) specify the green channel,
+// and the last 5 bits(0x001F) specify the blue channel, each on a scale from 0..31.
+void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles16, int selection)
+{
+	if (selection < -1 || selection >= (int)numTexTiles)
+	{
+		printf("ERROR: Textile selection must be between \"0\" and \"%d\" or \"all\", argument was \"%d\"", numTexTiles - 1, selection);
+		return 0;
+	}
+
+	// todo UM, ACTUALLY should just do 24-bit BMP.
+	// since we're not using the alpha channel, it's a waste of HDD space
+
+	if (selection == -1)
+	{
+		printf("Extracting all 16-bit textiles to 32-bit bitmap (BMP)...");
+	}
+	{
+		printf("Extracting 16-bit textile %d to 32-bit bitmap (BMP)...\n", selection);
+	}
+
+	// This function extracts a texture tile from the level into a bitmap file. The syntax is "trmod [FILE] EXTRACT TEXTILE [#/All]".
+
+	const unsigned w = 256;
+	const unsigned h = 256;
+
+	for (int t = (selection == -1 ? 0 : selection); t <= (selection == -1 ? numTexTiles - 1 : selection); ++t)
+	{
+		BYTE* img = malloc(4 * w * h);
+		//memset(img, 0, 4 * w * h); // Fill the whole image with 0s
+
+		for (int j = 0; j < h; j++)
+		{
+			for (int i = 0; i < w; i++)
+			{
+				unsigned int curpos = (j * w + i) * 2;
+				unsigned short pixel16;
+				BYTE a;
+				BYTE r;
+				BYTE g;
+				BYTE b;
+
+				memcpy(&pixel16, bytelist + p_TexTiles16[t] + curpos, 2);
+
+				a = pixel16 >> 15 == 1 ? 255 : 0;
+				r = (pixel16 >> 10) & 0b11111; // 5-bit red channel
+				g = (pixel16 >> 5) & 0b11111; // 5-bit green channel
+				b = pixel16 & 0b11111; // 5-bit blue channel
+
+				if (a == 0)
+				{
+					// TR2 transparency - full magenta
+					img[i * 4 + j * w * 4 + 2] = 255; // 8-bit red
+					img[i * 4 + j * w * 4 + 1] = 0;   // 8-bit green
+					img[i * 4 + j * w * 4 + 0] = 255; // 8-bit blue
+					img[i * 4 + j * w * 4 + 3] = 255; // Opaque (according to BMP)
+				}
+				else
+				{
+					// Full color / full opaque
+					img[i * 4 + j * w * 4 + 2] = r * 255 / 31; // Convert to 8-bit red
+					img[i * 4 + j * w * 4 + 1] = g * 255 / 31; // Convert to 8-bit green
+					img[i * 4 + j * w * 4 + 0] = b * 255 / 31; // Convert to 8-bit blue
+					img[i * 4 + j * w * 4 + 3] = 255; // Opaque
+				}
+			}
+		}
+
+		unsigned fnameLen = 12 + (t < 10 ? 1 : 2);
+		char* filename = malloc(fnameLen);
+		snprintf(filename, fnameLen, "textile%u.bmp", t);
+		printf("Writing \"%s\"...\n", filename);
+		writeBitmap32(img, filename, 256, 256);
+
+		free(img);
+		free(filename);
+	}
+}
+
 // This function replaces a texture tile in the level from a bitmap file. The syntax is "trmod [FILE] REPLACE TEXTILE [#] [FILENAME.BMP]".
-void tr2pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize)
+void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize)
 {
 	unsigned int selection = atoi(args[4]);
 	char* filename = args[5];
diff --git a/Source/tr2pc.h b/Source/tr2pc.h
index d15872a..8b26505 100644
--- a/Source/tr2pc.h
+++ b/Source/tr2pc.h
@@ -39,7 +39,8 @@ void tr2pc_get_zones(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned
 void tr2pc_add_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned fsize);
 void tr2pc_replace_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned fsize);
 void tr2pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_NumVertices[], unsigned p_NumSprites[], unsigned p_NumLights[], unsigned p_NumZSector[], unsigned p_NumStaticMeshes[], unsigned p_AlternateRoom[], unsigned p_NumFloorData, unsigned p_NumItems, unsigned p_NumSpriteSequences, unsigned p_NumCameras, unsigned p_NumDemoData, unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned p_NumSoundSources, unsigned fsize);
-void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, int selection);
-void tr2pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize);
+void tr2pc_extract_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, int selection);
+void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles16, int selection);
+void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize);
 
 #endif

From 500a0ffb1779327da255bf2613547402d36d0cf8 Mon Sep 17 00:00:00 2001
From: Aerik72 <dummy@github.com>
Date: Fri, 13 Aug 2021 00:41:01 -0500
Subject: [PATCH 5/5] TR2 texture replace working

---
 Source/tr1pc.c |   1 -
 Source/tr2pc.c | 131 +++++++++++++++++++++++++++++++++++++------------
 Source/tr2pc.h |   3 +-
 3 files changed, 101 insertions(+), 34 deletions(-)

diff --git a/Source/tr1pc.c b/Source/tr1pc.c
index 8f42d89..ea83356 100644
--- a/Source/tr1pc.c
+++ b/Source/tr1pc.c
@@ -3241,7 +3241,6 @@ void tr1pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, u
 
 	const short w = 256;
 	const short h = 256;
-	unsigned memorySize = 3 * w * h;
 
 	BYTE* bitmapImage = readBitmapFile(filename);
 	if (bitmapImage == NULL)
diff --git a/Source/tr2pc.c b/Source/tr2pc.c
index c20eac1..806333d 100644
--- a/Source/tr2pc.c
+++ b/Source/tr2pc.c
@@ -259,7 +259,7 @@ void tr2pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 	{
 		if (!strnicmp(args[3], "textile", 9))
 		{
-			tr2pc_extract_textile16(bytelist, args, numTexTiles, p_TexTiles16, !strnicmp(args[4], "all", 3) ? -1 : atoi(args[4]));
+			tr2pc_extract_textile(bytelist, args, numTexTiles, p_TexTiles16, !strnicmp(args[4], "all", 3) ? -1 : atoi(args[4]));
 		}
 		else if (!strnicmp(args[3], "textile8", 7))
 		{
@@ -270,7 +270,11 @@ void tr2pc_main(int argc, char *args[], char *bytelist, unsigned fsize){
 
 	if (!_strnicmp(args[2], "replace", 7))
 	{
-		if (!strnicmp(args[3], "textile8", 7))
+		if (!strnicmp(args[3], "textile", 9))
+		{
+			tr2pc_replace_textile(bytelist, args, numTexTiles, p_TexTiles16, fsize);
+		}
+		else if (!strnicmp(args[3], "textile8", 7))
 		{
 			printf("WARNING: 8-bit textures are a legacy feature, and will probably not render on a modern PC.\n");
 			tr2pc_replace_textile8(bytelist, args, numTexTiles, p_TexTiles8, palette8, fsize);
@@ -2992,12 +2996,70 @@ void tr2pc_extract_textile8(char* bytelist, char* args[], unsigned numTexTiles,
 	}
 }
 
+// This function replaces a texture tile in the level from a bitmap file. The syntax is "trmod [FILE] REPLACE TEXTILE [#] [FILENAME.BMP]".
+void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize)
+{
+	unsigned int selection = atoi(args[4]);
+	char* filename = args[5];
+
+	if (selection < 0 || selection >= numTexTiles)
+	{
+		printf("ERROR: Textile selection must be between \"0\" and \"%d\", argument was \"%d\"", numTexTiles - 1, selection);
+		return 0;
+	}
+
+	printf("Replacing 8-bit textile %d...\n", selection);
+
+	const short w = 256;
+	const short h = 256;
+	unsigned memorySize = 3 * w * h;
+
+	BYTE* bitmapImage = readBitmapFile(filename);
+	if (bitmapImage == NULL)
+	{
+		printf("ERROR: Could not read bitmap.\n");
+		return 0;
+	}
+
+	for (int j = 0; j < h; j++)
+	{
+		for (int i = 0; i < w; i++)
+		{
+			unsigned int curpos = j * w + i;
+			BYTE r;
+			BYTE g;
+			BYTE b;
+			BYTE pixelKey;
+
+			memcpy(&r, bitmapImage + curpos * 3 + 2, 1);
+			memcpy(&g, bitmapImage + curpos * 3 + 1, 1);
+			memcpy(&b, bitmapImage + curpos * 3 + 0, 1);
+
+			if (r == 255 && g == 0 && b == 255)
+			{
+				pixelKey = 0; // Reserved for pure-magenta aka transparent
+			}
+			else
+			{
+				pixelKey = findPixelKey(palette8, r, g, b);
+			}
+
+			unsigned int curposFlip = ((h - 1 - j) * w) + i; // Bitmap rows are stored bottom-up
+			memcpy(bytelist + p_TexTiles[selection] + curposFlip, &pixelKey, 1);
+		}
+	}
+
+	writeFile(args[1], bytelist, fsize);
+
+	free(bitmapImage);
+}
+
 // tr2_textile16 Textile16[NumTextiles]; // 16-bit (ARGB) textiles (NumTextiles * 131072 bytes)
 // The 16-bit textile array, which contains[tr_textile16] structures, specifies colours using 16 - bit ARGB,
 // where the highest bit (0x8000) is a crude alpha channel (really just a simple transparency: 0==transparent, 1==opaque).
 // The next 5 bits(0x7C00) specify the red channel, the next 5 bits(0x03E0) specify the green channel,
 // and the last 5 bits(0x001F) specify the blue channel, each on a scale from 0..31.
-void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles16, int selection)
+void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles16, int selection)
 {
 	if (selection < -1 || selection >= (int)numTexTiles)
 	{
@@ -3005,26 +3067,22 @@ void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles,
 		return 0;
 	}
 
-	// todo UM, ACTUALLY should just do 24-bit BMP.
-	// since we're not using the alpha channel, it's a waste of HDD space
-
 	if (selection == -1)
 	{
-		printf("Extracting all 16-bit textiles to 32-bit bitmap (BMP)...");
+		printf("Extracting all 16-bit textiles to 24-bit bitmap (BMP)...");
 	}
 	{
-		printf("Extracting 16-bit textile %d to 32-bit bitmap (BMP)...\n", selection);
+		printf("Extracting 16-bit textile %d to 24-bit bitmap (BMP)...\n", selection);
 	}
 
 	// This function extracts a texture tile from the level into a bitmap file. The syntax is "trmod [FILE] EXTRACT TEXTILE [#/All]".
 
-	const unsigned w = 256;
-	const unsigned h = 256;
+	const unsigned short w = 256;
+	const unsigned short h = 256;
 
 	for (int t = (selection == -1 ? 0 : selection); t <= (selection == -1 ? numTexTiles - 1 : selection); ++t)
 	{
-		BYTE* img = malloc(4 * w * h);
-		//memset(img, 0, 4 * w * h); // Fill the whole image with 0s
+		BYTE* img = malloc(3 * w * h);
 
 		for (int j = 0; j < h; j++)
 		{
@@ -3039,7 +3097,8 @@ void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles,
 
 				memcpy(&pixel16, bytelist + p_TexTiles16[t] + curpos, 2);
 
-				a = pixel16 >> 15 == 1 ? 255 : 0;
+				// Crack it
+				a = pixel16 >> 15;
 				r = (pixel16 >> 10) & 0b11111; // 5-bit red channel
 				g = (pixel16 >> 5) & 0b11111; // 5-bit green channel
 				b = pixel16 & 0b11111; // 5-bit blue channel
@@ -3047,18 +3106,16 @@ void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles,
 				if (a == 0)
 				{
 					// TR2 transparency - full magenta
-					img[i * 4 + j * w * 4 + 2] = 255; // 8-bit red
-					img[i * 4 + j * w * 4 + 1] = 0;   // 8-bit green
-					img[i * 4 + j * w * 4 + 0] = 255; // 8-bit blue
-					img[i * 4 + j * w * 4 + 3] = 255; // Opaque (according to BMP)
+					img[i * 3 + j * w * 3 + 2] = 255; // 8-bit red
+					img[i * 3 + j * w * 3 + 1] = 0;   // 8-bit green
+					img[i * 3 + j * w * 3 + 0] = 255; // 8-bit blue
 				}
 				else
 				{
 					// Full color / full opaque
-					img[i * 4 + j * w * 4 + 2] = r * 255 / 31; // Convert to 8-bit red
-					img[i * 4 + j * w * 4 + 1] = g * 255 / 31; // Convert to 8-bit green
-					img[i * 4 + j * w * 4 + 0] = b * 255 / 31; // Convert to 8-bit blue
-					img[i * 4 + j * w * 4 + 3] = 255; // Opaque
+					img[i * 3 + j * w * 3 + 2] = r * 255 / 31; // Convert to 8-bit red
+					img[i * 3 + j * w * 3 + 1] = g * 255 / 31; // Convert to 8-bit green
+					img[i * 3 + j * w * 3 + 0] = b * 255 / 31; // Convert to 8-bit blue
 				}
 			}
 		}
@@ -3067,7 +3124,7 @@ void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles,
 		char* filename = malloc(fnameLen);
 		snprintf(filename, fnameLen, "textile%u.bmp", t);
 		printf("Writing \"%s\"...\n", filename);
-		writeBitmap32(img, filename, 256, 256);
+		writeBitmap(img, filename, 256, 256);
 
 		free(img);
 		free(filename);
@@ -3075,7 +3132,11 @@ void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles,
 }
 
 // This function replaces a texture tile in the level from a bitmap file. The syntax is "trmod [FILE] REPLACE TEXTILE [#] [FILENAME.BMP]".
-void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize)
+// The 16-bit textile array, which contains[tr_textile16] structures, specifies colours using 16 - bit ARGB,
+// where the highest bit (0x8000) is a crude alpha channel (really just a simple transparency: 0==transparent, 1==opaque).
+// The next 5 bits(0x7C00) specify the red channel, the next 5 bits(0x03E0) specify the green channel,
+// and the last 5 bits(0x001F) specify the blue channel, each on a scale from 0..31.
+void tr2pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, unsigned fsize)
 {
 	unsigned int selection = atoi(args[4]);
 	char* filename = args[5];
@@ -3086,16 +3147,15 @@ void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles,
 		return 0;
 	}
 
-	printf("Replacing 8-bit textile %d...\n", selection);
+	printf("Replacing 16-bit textile %d with 24-bit bitmap (BMP)...\n", selection);
 
 	const short w = 256;
 	const short h = 256;
-	unsigned memorySize = 3 * w * h;
 
 	BYTE* bitmapImage = readBitmapFile(filename);
 	if (bitmapImage == NULL)
 	{
-		printf("ERROR: Could not read bitmap.\n");
+		printf("ERROR: Could not read 24-bit bitmap \"%s\".\n", filename);
 		return 0;
 	}
 
@@ -3104,26 +3164,33 @@ void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles,
 		for (int i = 0; i < w; i++)
 		{
 			unsigned int curpos = j * w + i;
+			BYTE a;
 			BYTE r;
 			BYTE g;
 			BYTE b;
-			BYTE pixelKey;
-
+			unsigned short pixel16;
+			
 			memcpy(&r, bitmapImage + curpos * 3 + 2, 1);
 			memcpy(&g, bitmapImage + curpos * 3 + 1, 1);
 			memcpy(&b, bitmapImage + curpos * 3 + 0, 1);
 
 			if (r == 255 && g == 0 && b == 255)
 			{
-				pixelKey = 0; // Reserved for pure-magenta aka transparent
+				pixel16 = 0; // Reserved for pure-magenta aka transparent
 			}
 			else
 			{
-				pixelKey = findPixelKey(palette8, r, g, b);
+				a = 1; // Full color / full opaque
+				r = r * 31 / 255; // Convert to 5-bit red
+				g = g * 31 / 255; // Convert to 5-bit green
+				b = b * 31 / 255; // Convert to 5-bit blue
+
+				// Pack it
+				pixel16 = (a << 15) | (r << 10) | (g << 5) | b;
 			}
 
-			unsigned int curposFlip = ((h - 1 - j) * w) + i; // Bitmap rows are stored bottom-up
-			memcpy(bytelist + p_TexTiles[selection] + curposFlip, &pixelKey, 1);
+			unsigned int curposFlip = (((h - 1 - j) * w) + i) * 2; // Bitmap rows are stored bottom-up
+			memcpy(bytelist + p_TexTiles[selection] + curposFlip, &pixel16, 2);
 		}
 	}
 
diff --git a/Source/tr2pc.h b/Source/tr2pc.h
index 8b26505..2f207ed 100644
--- a/Source/tr2pc.h
+++ b/Source/tr2pc.h
@@ -40,7 +40,8 @@ void tr2pc_add_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned
 void tr2pc_replace_zone(char *bytelist, char *args[], unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned fsize);
 void tr2pc_get_offset(char *bytelist, char *args[], unsigned argc, unsigned p_NumVertices[], unsigned p_NumSprites[], unsigned p_NumLights[], unsigned p_NumZSector[], unsigned p_NumStaticMeshes[], unsigned p_AlternateRoom[], unsigned p_NumFloorData, unsigned p_NumItems, unsigned p_NumSpriteSequences, unsigned p_NumCameras, unsigned p_NumDemoData, unsigned p_NumBoxes, unsigned p_NumOverlaps, unsigned p_NumSoundSources, unsigned fsize);
 void tr2pc_extract_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, int selection);
-void tr2pc_extract_textile16(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles16, int selection);
+void tr2pc_extract_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles16, int selection);
 void tr2pc_replace_textile8(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, BYTE* palette8, unsigned fsize);
+void tr2pc_replace_textile(char* bytelist, char* args[], unsigned numTexTiles, unsigned* p_TexTiles, unsigned fsize);
 
 #endif