From 72531e61dbe53cbc4aedd4a8ea4aee4c8baed36f Mon Sep 17 00:00:00 2001
From: Mitch Richters <mjr4077au@gmail.com>
Date: Sun, 7 Nov 2021 11:37:12 +1100
Subject: [PATCH] - gameinput.cpp/h: Consolidate all the return to zero code
 for angles and horizons into class members, using technique from `horizoff`
 as basis.

---
 source/core/gameinput.cpp | 34 ++++++++--------------------------
 source/core/gameinput.h   | 16 ++++++++++++++--
 2 files changed, 22 insertions(+), 28 deletions(-)

diff --git a/source/core/gameinput.cpp b/source/core/gameinput.cpp
index dee143086..a1773f4ea 100644
--- a/source/core/gameinput.cpp
+++ b/source/core/gameinput.cpp
@@ -320,14 +320,8 @@ void PlayerHorizon::applyinput(float const horz, ESyncBits* actions, double cons
 		// return to center if conditions met.
 		if ((*actions & SB_CENTERVIEW) && !(*actions & (SB_LOOK_UP|SB_LOOK_DOWN)) && horiz.asq16())
 		{
-			// move horiz back to 0
-			horiz -= getscaledhoriz(CNTRSPEED, scaleAdjust, &horiz);
-			if (abs(horiz.asq16()) < (FRACUNIT >> 2))
-			{
-				// not looking anymore because horiz is back at 0
-				horiz = q16horiz(0);
-				*actions &= ~SB_CENTERVIEW;
-			}
+			scaletozero(horiz, CNTRSPEED, scaleAdjust);
+			if (!horiz.asq16()) *actions &= ~SB_CENTERVIEW;
 		}
 	}
 	else
@@ -374,20 +368,9 @@ enum
 
 void PlayerAngle::applyinput(float const avel, ESyncBits* actions, double const scaleAdjust)
 {
-	if (rotscrnang.asbam())
-	{
-		// return rotscrnang to 0
-		auto sgn = Sgn(rotscrnang.signedbam());
-		rotscrnang -= getscaledangle(LOOKROTRETBASE, scaleAdjust, &rotscrnang, sgn);
-		if (sgn != Sgn(rotscrnang.signedbam())) rotscrnang = bamang(0);
-	}
-
-	if (look_ang.asbam())
-	{
-		// return look_ang to 0
-		look_ang -= getscaledangle(+LOOKROTRETBASE * 0.5, scaleAdjust, &look_ang);
-		if (abs(look_ang.signedbam()) < (BAMUNIT >> 2)) look_ang = bamang(0);
-	}
+	// Process angle return to zeros.
+	if (rotscrnang.asbam()) scaletozero(rotscrnang, LOOKROTRETBASE, scaleAdjust);
+	if (look_ang.asbam()) scaletozero(look_ang, +LOOKROTRETBASE * 0.5, scaleAdjust);
 
 	// Process keyboard input.
 	auto doLookKeys = [&](ESyncBits_ const key, double const direction)
@@ -501,16 +484,15 @@ void PlayerHorizon::calcviewpitch(vec2_t const pos, binangle const ang, bool con
 		{
 			// tilt when climbing but you can't even really tell it.
 			if (horizoff.asq16() < IntToFixed(100))
-			{	auto temphorizoff = buildhoriz(100) - horizoff;
+			{
+				auto temphorizoff = buildhoriz(100) - horizoff;
 				horizoff += getscaledhoriz(4.375, scaleAdjust, &temphorizoff, 1.);
 			}
 		}
 		else if (horizoff.asq16())
 		{
 			// Make horizoff grow towards 0 since horizoff is not modified when you're not on a slope.
-			auto sgn = Sgn(horizoff.asq16());
-			horizoff -= getscaledhoriz(4.375, scaleAdjust, &horizoff, sgn);
-			if (sgn != Sgn(horizoff.asq16())) horizoff = q16horiz(0);
+			scaletozero(horizoff, 4.375, scaleAdjust, Sgn(horizoff.asq16()));
 		}
 	}
 }
diff --git a/source/core/gameinput.h b/source/core/gameinput.h
index 1920792aa..3d372acff 100644
--- a/source/core/gameinput.h
+++ b/source/core/gameinput.h
@@ -70,11 +70,17 @@ struct PlayerHorizon
 	// Draw code helpers.
 	double horizsumfrac(double const smoothratio) { return (!SyncInput() ? sum() : interpolatedsum(smoothratio)).asbuildf() * (1. / 16.); }
 
-	// Ticrate scale helper.
+	// Ticrate scale helpers.
 	fixedhoriz getscaledhoriz(double const value, double const scaleAdjust = 1., fixedhoriz* const object = nullptr, double const push = 0.)
 	{
 		return buildfhoriz(scaleAdjust * (((object ? object->asbuildf() : 1.) * getTicrateScale(value)) + push));
 	}
+	void scaletozero(fixedhoriz& object, double const value, double const scaleAdjust, double const push = 0.)
+	{
+		auto sgn = Sgn(object.asq16());
+		object  -= getscaledhoriz(value, scaleAdjust, &object, push == 0 ? sgn * (1. / 3.) : push);
+		if (sgn != Sgn(object.asq16())) object = q16horiz(0);
+	}
 
 	// Ticrate playsim adjustment processor.
 	void processhelpers(double const scaleAdjust)
@@ -181,11 +187,17 @@ struct PlayerAngle
 	double look_anghalf(double const smoothratio) { return (!SyncInput() ? look_ang : interpolatedlookang(smoothratio)).signedbuildf() * 0.5; }
 	double looking_arc(double const smoothratio) { return fabs((!SyncInput() ? look_ang : interpolatedlookang(smoothratio)).signedbuildf()) * (1. / 9.); }
 
-	// Ticrate scale helper.
+	// Ticrate scale helpers.
 	binangle getscaledangle(double const value, double const scaleAdjust = 1., binangle* const object = nullptr, double const push = 0.)
 	{
 		return buildfang(scaleAdjust * (((object ? object->signedbuildf() : 1.) * getTicrateScale(value)) + push));
 	}
+	void scaletozero(binangle& object, double const value, double const scaleAdjust, double const push = 0.)
+	{
+		auto sgn = Sgn(object.signedbam());
+		object  -= getscaledangle(value, scaleAdjust, &object, push == 0 ? sgn * (1. / 3.) : push);
+		if (sgn != Sgn(object.signedbam())) object = bamang(0);
+	}
 
 	// Ticrate playsim adjustment processor.
 	void processhelpers(double const scaleAdjust)