Work on FLIPX/FLIPX support:

*Added FLIPX/FLIPY support for multi-patch textures and single-patch textures without holes
*Added FLIPY support for single-patch textures with holes; I'll sort FLIPX support out later

src/r_data.c

@@ -173,6 +173,43 @@ static inline void R_DrawColumnInCache(column_t *patch, UINT8 *cache, INT32 orig
 	}
 }
 
+static inline void R_DrawFlippedColumnInCache(column_t *patch, UINT8 *cache, INT32 originy, INT32 cacheheight, INT32 patchheight)
+{
+	INT32 count, position;
+	UINT8 *source, *dest;
+	INT32 topdelta, prevdelta = -1;
+
+	while (patch->topdelta != 0xff)
+	{
+		topdelta = patch->topdelta;
+		if (topdelta <= prevdelta)
+			topdelta += prevdelta;
+		prevdelta = topdelta;
+		topdelta = patchheight-patch->length-topdelta;
+		source = (UINT8 *)patch + 2 + patch->length; // patch + 3 + (patch->length-1)
+		count = patch->length;
+		position = originy + topdelta;
+
+		if (position < 0)
+		{
+			count += position;
+			position = 0;
+		}
+
+		if (position + count > cacheheight)
+			count = cacheheight - position;
+
+		dest = cache + position;
+		if (count > 0)
+		{
+			for (; dest < cache + position + count; --source)
+				*dest++ = *source;
+		}
+
+		patch = (column_t *)((UINT8 *)patch + patch->length + 4);
+	}
+}
+
 //
 // R_GenerateTexture
 //
@@ -191,7 +228,7 @@ static UINT8 *R_GenerateTexture(size_t texnum)
 	texture_t *texture;
 	texpatch_t *patch;
 	patch_t *realpatch;
-	int x, x1, x2, i;
+	int x, x1, x2, i, width, height;
 	size_t blocksize;
 	column_t *patchcol;
 	UINT32 *colofs;
@@ -239,6 +276,7 @@ static UINT8 *R_GenerateTexture(size_t texnum)
 		if (holey)
 		{
 			texture->holes = true;
+			texture->flip = patch->flip;
 			blocksize = W_LumpLengthPwad(patch->wad, patch->lump);
 			block = Z_Calloc(blocksize, PU_STATIC, // will change tag at end of this function
 				&texturecache[texnum]);
@@ -259,6 +297,7 @@ static UINT8 *R_GenerateTexture(size_t texnum)
 
 	// multi-patch textures (or 'composite')
 	texture->holes = false;
+	texture->flip = 0;
 	blocksize = (texture->width * 4) + (texture->width * texture->height);
 	texturememory += blocksize;
 	block = Z_Malloc(blocksize+1, PU_STATIC, &texturecache[texnum]);
@@ -277,7 +316,9 @@ static UINT8 *R_GenerateTexture(size_t texnum)
 	{
 		realpatch = W_CacheLumpNumPwad(patch->wad, patch->lump, PU_CACHE);
 		x1 = patch->originx;
-		x2 = x1 + SHORT(realpatch->width);
+		width = SHORT(realpatch->width);
+		height = SHORT(realpatch->height);
+		x2 = x1 + width;
 
 		if (x1 < 0)
 			x = 0;
@@ -289,11 +330,17 @@ static UINT8 *R_GenerateTexture(size_t texnum)
 
 		for (; x < x2; x++)
 		{
-			patchcol = (column_t *)((UINT8 *)realpatch + LONG(realpatch->columnofs[x-x1]));
+			if (patch->flip & 1)
+				patchcol = (column_t *)((UINT8 *)realpatch + LONG(realpatch->columnofs[(x1+width-1)-x]));
+			else
+				patchcol = (column_t *)((UINT8 *)realpatch + LONG(realpatch->columnofs[x-x1]));
 
 			// generate column ofset lookup
 			colofs[x] = LONG((x * texture->height) + (texture->width*4));
-			R_DrawColumnInCache(patchcol, block + LONG(colofs[x]), patch->originy, texture->height);
+			if (patch->flip & 2)
+				R_DrawFlippedColumnInCache(patchcol, block + LONG(colofs[x]), patch->originy, texture->height, height);
+			else
+				R_DrawColumnInCache(patchcol, block + LONG(colofs[x]), patch->originy, texture->height);
 		}
 	}
 
@@ -469,6 +516,7 @@ void R_LoadTextures(void)
 				texture->height = SHORT(patchlump->height)*patchcount;
 				texture->patchcount = patchcount;
 				texture->holes = false;
+				texture->flip = 0;
 
 				// Allocate information for the texture's patches.
 				for (k = 0; k < patchcount; k++)
@@ -479,6 +527,7 @@ void R_LoadTextures(void)
 					patch->originy = (INT16)(k*patchlump->height);
 					patch->wad = (UINT16)w;
 					patch->lump = texstart + j;
+					patch->flip = 0;
 				}
 
 				Z_Unlock(patchlump);

src/r_data.h

@@ -43,6 +43,7 @@ typedef struct
 	char name[8];
 	INT16 width, height;
 	boolean holes;
+	UINT8 flip; // 1 = flipx, 2 = flipy, 3 = both
 
 	// All the patches[patchcount] are drawn back to front into the cached texture.
 	INT16 patchcount;

src/r_segs.c

@@ -276,6 +276,13 @@ static void R_Render2sidedMultiPatchColumn(column_t *column)
 	}
 }
 
+// quick wrapper for R_DrawFlippedMaskedColumn so it can be set as a colfunc_2s value
+// uses column2s_length for texture->height as above
+static void R_DrawFlippedMaskedSegColumn(column_t *column)
+{
+	R_DrawFlippedMaskedColumn(column, column2s_length);
+}
+
 void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 {
 	size_t pindex;
@@ -347,7 +354,15 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 	// handle case where multipatch texture is drawn on a 2sided wall, multi-patch textures
 	// are not stored per-column with post info in SRB2
 	if (textures[texnum]->holes)
-		colfunc_2s = R_DrawMaskedColumn; // render the usual 2sided single-patch packed texture
+	{
+		if (textures[texnum]->flip & 2) // vertically flipped?
+		{
+			colfunc_2s = R_DrawFlippedMaskedSegColumn;
+			column2s_length = textures[texnum]->height;
+		}
+		else
+			colfunc_2s = R_DrawMaskedColumn; // render the usual 2sided single-patch packed texture
+	}
 	else
 	{
 		colfunc_2s = R_Render2sidedMultiPatchColumn; // render multipatch with no holes (no post_t info)
@@ -700,6 +715,14 @@ static void R_DrawRepeatMaskedColumn(column_t *col)
 	} while (sprtopscreen < sprbotscreen);
 }
 
+static void R_DrawRepeatFlippedMaskedColumn(column_t *col)
+{
+	do {
+		R_DrawFlippedMaskedColumn(col, column2s_length);
+		sprtopscreen += dc_texheight*spryscale;
+	} while (sprtopscreen < sprbotscreen);
+}
+
 //
 // R_RenderThickSideRange
 // Renders all the thick sides in the given range.
@@ -1027,7 +1050,15 @@ void R_RenderThickSideRange(drawseg_t *ds, INT32 x1, INT32 x2, ffloor_t *pfloor)
 	//faB: handle case where multipatch texture is drawn on a 2sided wall, multi-patch textures
 	//     are not stored per-column with post info anymore in Doom Legacy
 	if (textures[texnum]->holes)
-		colfunc_2s = R_DrawRepeatMaskedColumn;                    //render the usual 2sided single-patch packed texture
+	{
+		if (textures[texnum]->flip & 2) // vertically flipped?
+		{
+			colfunc_2s = R_DrawRepeatFlippedMaskedColumn;
+			column2s_length = textures[texnum]->height;
+		}
+		else
+			colfunc_2s = R_DrawRepeatMaskedColumn; // render the usual 2sided single-patch packed texture
+	}
 	else
 	{
 		colfunc_2s = R_Render2sidedMultiPatchColumn;        //render multipatch with no holes (no post_t info)

src/r_things.c

@@ -712,7 +712,7 @@ void R_DrawMaskedColumn(column_t *column)
 	dc_texturemid = basetexturemid;
 }
 
-static void R_DrawFlippedMaskedColumn(column_t *column, INT32 texheight)
+void R_DrawFlippedMaskedColumn(column_t *column, INT32 texheight)
 {
 	INT32 topscreen;
 	INT32 bottomscreen;

src/r_things.h

@@ -46,6 +46,7 @@ extern fixed_t windowtop;
 extern fixed_t windowbottom;
 
 void R_DrawMaskedColumn(column_t *column);
+void R_DrawFlippedMaskedColumn(column_t *column, INT32 texheight);
 void R_SortVisSprites(void);
 
 //faB: find sprites in wadfile, replace existing, add new ones