From 8422c88063405162a0a065bef827193120fd80ab Mon Sep 17 00:00:00 2001
From: Jaime Passos <lazymyuutsu@gmail.com>
Date: Tue, 17 Dec 2019 13:25:55 -0300
Subject: [PATCH] optimise R_CacheRotSprite

---
 src/r_patch.c | 60 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 22 deletions(-)

diff --git a/src/r_patch.c b/src/r_patch.c
index e538c1775..e7ee9dd05 100644
--- a/src/r_patch.c
+++ b/src/r_patch.c
@@ -1096,6 +1096,35 @@ void R_LoadSpriteInfoLumps(UINT16 wadnum, UINT16 numlumps)
 	}
 }
 
+static UINT16 GetPatchPixel(patch_t *patch, INT32 x, INT32 y, boolean flip)
+{
+	fixed_t ofs;
+	column_t *column;
+	UINT8 *source;
+
+	if (x < SHORT(patch->width))
+	{
+		INT32 topdelta, prevdelta = -1;
+		column = (column_t *)((UINT8 *)patch + LONG(patch->columnofs[flip ? (patch->width-1-x) : x]));
+		while (column->topdelta != 0xff)
+		{
+			topdelta = column->topdelta;
+			if (topdelta <= prevdelta)
+				topdelta += prevdelta;
+			prevdelta = topdelta;
+			source = (UINT8 *)(column) + 3;
+			for (ofs = 0; ofs < column->length; ofs++)
+			{
+				if ((topdelta + ofs) == y)
+					return source[ofs];
+			}
+			column = (column_t *)((UINT8 *)column + column->length + 4);
+		}
+	}
+
+	return 0xFF00;
+}
+
 #ifdef ROTSPRITE
 //
 // R_CacheRotSprite
@@ -1108,8 +1137,8 @@ void R_CacheRotSprite(spritenum_t sprnum, UINT8 frame, spriteinfo_t *sprinfo, sp
 	INT32 angle;
 	patch_t *patch;
 	patch_t *newpatch;
-	UINT16 *rawsrc, *rawdst;
-	size_t size, size2;
+	UINT16 *rawdst;
+	size_t size;
 	INT32 bflip = (flip != 0x00);
 
 #define SPRITE_XCENTER (leftoffset)
@@ -1154,16 +1183,6 @@ void R_CacheRotSprite(spritenum_t sprnum, UINT8 frame, spriteinfo_t *sprinfo, sp
 			leftoffset = width - leftoffset;
 		}
 
-		// Draw the sprite to a temporary buffer.
-		size = (width*height);
-		rawsrc = Z_Malloc(size * sizeof(UINT16), PU_STATIC, NULL);
-
-		// can't memset here
-		for (i = 0; i < size; i++)
-			rawsrc[i] = 0xFF00;
-
-		R_PatchToFlat_16bpp(patch, rawsrc, bflip);
-
 		// Don't cache angle = 0
 		for (angle = 1; angle < ROTANGLES; angle++)
 		{
@@ -1231,17 +1250,15 @@ void R_CacheRotSprite(spritenum_t sprnum, UINT8 frame, spriteinfo_t *sprinfo, sp
 #undef BOUNDARYADJUST
 			}
 
-			size2 = (newwidth * newheight);
-			if (!size2)
-				size2 = size;
+			// Draw the rotated sprite to a temporary buffer.
+			size = (newwidth * newheight);
+			if (!size)
+				size = (width * height);
 
-			rawdst = Z_Malloc(size2 * sizeof(UINT16), PU_STATIC, NULL);
-
-			// can't memset here
-			for (i = 0; i < size2; i++)
+			rawdst = Z_Malloc(size * sizeof(UINT16), PU_STATIC, NULL);
+			for (i = 0; i < size; i++)
 				rawdst[i] = 0xFF00;
 
-			// Draw the rotated sprite to a temporary buffer.
 			for (dy = 0; dy < newheight; dy++)
 			{
 				for (dx = 0; dx < newwidth; dx++)
@@ -1253,7 +1270,7 @@ void R_CacheRotSprite(spritenum_t sprnum, UINT8 frame, spriteinfo_t *sprinfo, sp
 					sx >>= FRACBITS;
 					sy >>= FRACBITS;
 					if (sx >= 0 && sy >= 0 && sx < width && sy < height)
-						rawdst[(dy*newwidth)+dx] = rawsrc[(sy*width)+sx];
+						rawdst[(dy*newwidth)+dx] = GetPatchPixel(patch, sx, sy, bflip);
 				}
 			}
 
@@ -1290,7 +1307,6 @@ void R_CacheRotSprite(spritenum_t sprnum, UINT8 frame, spriteinfo_t *sprinfo, sp
 		sprframe->rotsprite.cached[rot] = true;
 
 		// free image data
-		Z_Free(rawsrc);
 		Z_Free(patch);
 	}
 #undef SPRITE_XCENTER