From 696e4050381de1223c21867549ab64af76f641e5 Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Tue, 6 Apr 2021 03:57:53 -0700
Subject: [PATCH] Lift the wheels of your jart a little when sliptiding

---
 src/k_kart.c          |  6 ++++++
 src/k_kart.h          |  1 +
 src/p_user.c          |  4 ----
 src/r_patchrotation.c | 19 +++++++++++++++++--
 src/tables.h          |  6 ++++++
 5 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/k_kart.c b/src/k_kart.c
index fb899360a..237970120 100644
--- a/src/k_kart.c
+++ b/src/k_kart.c
@@ -7539,6 +7539,12 @@ boolean K_PlayerEBrake(player_t *player)
 	&& player->powers[pw_nocontrol] == 0;
 }
 
+SINT8 K_Sliptiding(player_t *player)
+{
+	const INT32 *p = player->kartstuff;
+	return p[k_drift] ? 0 : p[k_aizdriftstrat];
+}
+
 static void K_KartSpindashDust(mobj_t *parent)
 {
 	fixed_t rad = FixedDiv(FixedHypot(parent->radius, parent->radius), parent->scale);
diff --git a/src/k_kart.h b/src/k_kart.h
index da40df761..8a862ba71 100644
--- a/src/k_kart.h
+++ b/src/k_kart.h
@@ -96,6 +96,7 @@ UINT16 K_GetKartButtons(player_t *player);
 SINT8 K_GetForwardMove(player_t *player);
 fixed_t K_3dKartMovement(player_t *player);
 boolean K_PlayerEBrake(player_t *player);
+SINT8 K_Sliptiding(player_t *player);
 void K_AdjustPlayerFriction(player_t *player);
 void K_MoveKartPlayer(player_t *player, boolean onground);
 void K_CheckSpectateStatus(void);
diff --git a/src/p_user.c b/src/p_user.c
index 8553d9279..39e0e0b67 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -4252,10 +4252,6 @@ Quaketilt (player_t *player)
 	fixed_t speed;
 
 	boolean sliptiding = K_Sliptiding(player);
-		(
-				player->kartstuff[k_aizdriftstrat] != 0 &&
-				player->kartstuff[k_drift]         == 0
-		);
 
 	if (delta == (INT32)ANGLE_180)/* FUCK YOU HAVE A HACK */
 	{
diff --git a/src/r_patchrotation.c b/src/r_patchrotation.c
index 769e4c92b..f4165f3ff 100644
--- a/src/r_patchrotation.c
+++ b/src/r_patchrotation.c
@@ -14,6 +14,7 @@
 #include "z_zone.h"
 #include "w_wad.h"
 #include "r_main.h" // R_PointToAngle
+#include "k_kart.h" // K_Sliptiding
 
 #ifdef ROTSPRITE
 fixed_t rollcosang[ROTANGLES];
@@ -22,13 +23,27 @@ fixed_t rollsinang[ROTANGLES];
 angle_t R_SpriteRotationAngle(mobj_t *mobj)
 {
 	angle_t viewingAngle = R_PointToAngle(mobj->x, mobj->y);
+	angle_t angleDelta = (viewingAngle - mobj->angle);
 
 	fixed_t pitchMul = -FINESINE(viewingAngle >> ANGLETOFINESHIFT);
 	fixed_t rollMul = FINECOSINE(viewingAngle >> ANGLETOFINESHIFT);
 
-	angle_t rollOrPitch = FixedMul(mobj->pitch, pitchMul) + FixedMul(mobj->roll, rollMul);
+	angle_t sliptideLift = mobj->player
+		? K_Sliptiding(mobj->player) * ANGLE_11hh : 0;
 
-	return (rollOrPitch + mobj->rollangle);
+	angle_t rollOrPitch = FixedMul(mobj->pitch, pitchMul) + FixedMul(mobj->roll, rollMul);
+	angle_t rollAngle = (rollOrPitch + mobj->rollangle);
+
+	if (sliptideLift)
+	{
+		/* (from side) tilt downward if turning
+		   toward camera, upward if away. */
+		rollAngle +=
+			FixedMul(sliptideLift, FINESINE(AbsAngle(angleDelta) >> ANGLETOFINESHIFT)) +
+			FixedMul(sliptideLift, FINECOSINE(angleDelta >> ANGLETOFINESHIFT));
+	}
+
+	return rollAngle;
 }
 
 INT32 R_GetRollAngle(angle_t rollangle)
diff --git a/src/tables.h b/src/tables.h
index a34b95ad2..e9ce14484 100644
--- a/src/tables.h
+++ b/src/tables.h
@@ -93,6 +93,12 @@ FUNCMATH FUNCINLINE static ATTRINLINE angle_t InvAngle(angle_t a)
 {
 	return (ANGLE_MAX-a)+1;
 }
+
+// 315 = 45
+FUNCMATH FUNCINLINE static ATTRINLINE angle_t AbsAngle(angle_t a)
+{
+	return a & ANGLE_180 ? InvAngle(a) : a;
+}
 // angle_t to fixed_t f(ANGLE_45) = 45*FRACUNIT
 FUNCMATH fixed_t AngleFixed(angle_t af);
 // fixed_t to angle_t f(45*FRACUNIT) = ANGLE_45