From 057b8a73546446a30fd7948a771f48d35ec2eda0 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sat, 10 Apr 2021 12:54:29 +0200
Subject: [PATCH] - cleanup of bvectan family of functions.

This can be greatly simplified to a single bvectangbam function using atan2 directly.
---
 source/build/src/polymost.cpp             |  2 +-
 source/core/binaryangle.h                 | 47 +----------------------
 source/core/rendering/scene/hw_portal.cpp |  5 ++-
 source/games/sw/src/player.cpp            |  4 +-
 4 files changed, 10 insertions(+), 48 deletions(-)

diff --git a/source/build/src/polymost.cpp b/source/build/src/polymost.cpp
index 307111c3c..118212656 100644
--- a/source/build/src/polymost.cpp
+++ b/source/build/src/polymost.cpp
@@ -3315,7 +3315,7 @@ void renderPrepareMirror(int32_t dax, int32_t day, int32_t daz, fixed_t daang, f
 
     *tposx = (x << 1) + Scale(dx, i, j) - dax;
     *tposy = (y << 1) + Scale(dy, i, j) - day;
-    *tang = ((bvectangq16(dx, dy) << 1) - daang) & 0x7FFFFFF;
+    *tang = ((bvectangbam(dx, dy).asq16() << 1) - daang) & 0x7FFFFFF;
 
     inpreparemirror = 1;
 
diff --git a/source/core/binaryangle.h b/source/core/binaryangle.h
index e4d86116a..a0690d734 100644
--- a/source/core/binaryangle.h
+++ b/source/core/binaryangle.h
@@ -502,54 +502,11 @@ inline FSerializer &Serialize(FSerializer &arc, const char *key, fixedhoriz &obj
 
 //---------------------------------------------------------------------------
 //
-// Double-precision implementation of `getangle()` with associated wrappers and helper functions.
+// High precision vector angle function, mainly for the renderer.
 //
 //---------------------------------------------------------------------------
 
-inline double bradarangf(double vect)
-{
-	return atan(vect) * BRadAngScale;
-}
-inline double bvectangf(int32_t x, int32_t y)
-{
-	if ((x | y) == 0)
-	{
-		return 0;
-	}
-	else if (x == 0)
-	{
-		return 512 + ((y < 0) << 10);
-	}
-	else if (y == 0)
-	{
-		return ((x < 0) << 10);
-	}
-	else if (x == y)
-	{
-		return 256 + ((x < 0) << 10);
-	}
-	else if (x == -y)
-	{
-		return 768 + ((x > 0) << 10);
-	}
-	else if (abs(x) > abs(y))
-	{
-		return fmod(bradarangf(double(y) / x) + ((x < 0) << 10), 2048.);
-	}
-	else
-	{
-		return fmod(bradarangf(double(x) / -y) + 512 + ((y < 0) << 10), 2048.);
-	}
-}
-inline int32_t bvectang(int32_t x, int32_t y)
-{
-	return xs_CRoundToInt(bvectangf(x, y));
-}
-inline fixed_t bvectangq16(int32_t x, int32_t y)
-{
-	return FloatToFixed(bvectangf(x, y));
-}
 inline binangle bvectangbam(int32_t x, int32_t y)
 {
-	return bamang(xs_CRoundToUInt(bvectangf(x, y) * BAMUNIT));
+	return radang(atan2(y, x));
 }
diff --git a/source/core/rendering/scene/hw_portal.cpp b/source/core/rendering/scene/hw_portal.cpp
index db37b870f..cf35cc320 100644
--- a/source/core/rendering/scene/hw_portal.cpp
+++ b/source/core/rendering/scene/hw_portal.cpp
@@ -574,7 +574,10 @@ bool HWMirrorPortal::Setup(HWDrawInfo *di, FRenderState &rstate, Clipper *clippe
 
 	int newx = int((x << 1) + Scale(dx, i, j) - view.x);
 	int newy = int((y << 1) + Scale(dy, i, j) - view.y);
-	auto newan = bamang(int64_t((bvectangf(dx, dy) * (BAMUNIT << 1)) - vp.RotAngle) & 0xFFFFFFFF);
+
+	auto myan = bvectangbam(dx, dy);
+	auto newan = myan + myan - bamang(vp.RotAngle);
+
 	vp.RotAngle = newan.asbam();
 	vp.SectNums = nullptr;
 	vp.SectCount = line->sector;
diff --git a/source/games/sw/src/player.cpp b/source/games/sw/src/player.cpp
index 766b511f0..a8ab12403 100644
--- a/source/games/sw/src/player.cpp
+++ b/source/games/sw/src/player.cpp
@@ -7148,7 +7148,9 @@ domovethings(void)
         // auto tracking mode for single player multi-game
         if (numplayers <= 1 && PlayerTrackingMode && pnum == screenpeek && screenpeek != myconnectindex)
         {
-            Player[screenpeek].angle.settarget(bvectangf(Player[myconnectindex].posx - Player[screenpeek].posx, Player[myconnectindex].posy - Player[screenpeek].posy));
+            int deltax = Player[myconnectindex].posx - Player[screenpeek].posx;
+            int deltay = Player[myconnectindex].posy - Player[screenpeek].posy;
+            Player[screenpeek].angle.settarget(bvectangbam(deltax, deltay));
         }
 
         if (!TEST(pp->Flags, PF_DEAD))