From 882622d2e70616376e81f82b8471645a1ac75721 Mon Sep 17 00:00:00 2001
From: toasterbabe <rollerorbital@gmail.com>
Date: Thu, 2 Jun 2016 16:42:07 +0100
Subject: [PATCH] ...I made two major mistakes with P_GetMobjGravity.

*Didn't take into account object scale
*Doubled force when on the ground (ignore what the comment of the line I moved says, it was relevant for slopes...)

This also led to a mistake with slopes, where I was double-multiplying by the gravity constant to get half (because of a quirk of numbers...)
---
 src/p_mobj.c   | 10 ++++++----
 src/p_slopes.c | 12 +++---------
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/p_mobj.c b/src/p_mobj.c
index acf5b1b36..843123d57 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -1316,9 +1316,6 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 	if (mo->eflags & MFE_UNDERWATER && !goopgravity)
 		gravityadd = gravityadd/3;
 
-	if (!mo->momz) // mobj at stop, no floor, so feel the push of gravity!
-		gravityadd <<= 1;
-
 	if (mo->player)
 	{
 		if (mo->player->charability == CA_FLY && (mo->player->powers[pw_tailsfly]
@@ -1402,6 +1399,8 @@ fixed_t P_GetMobjGravity(mobj_t *mo)
 	if (mo->player && !!(mo->eflags & MFE_VERTICALFLIP) != wasflip)
 		P_PlayerFlip(mo);
 
+	gravityadd = FixedMul(gravityadd, mo->scale);
+
 	return gravityadd;
 }
 
@@ -1416,8 +1415,11 @@ void P_CheckGravity(mobj_t *mo, boolean affect)
 {
 	fixed_t gravityadd = P_GetMobjGravity(mo);
 
+	if (!mo->momz) // mobj at stop, no floor, so feel the push of gravity!
+		gravityadd <<= 1;
+
 	if (affect)
-		mo->momz += FixedMul(gravityadd, mo->scale);
+		mo->momz += gravityadd;
 
 	if (mo->type == MT_SKIM && mo->z + mo->momz <= mo->watertop && mo->z >= mo->watertop)
 	{
diff --git a/src/p_slopes.c b/src/p_slopes.c
index ec07ab2fe..ed25f00f3 100644
--- a/src/p_slopes.c
+++ b/src/p_slopes.c
@@ -812,7 +812,7 @@ void P_HandleSlopeLanding(mobj_t *thing, pslope_t *slope)
 	mom.y = thing->momy;
 	mom.z = thing->momz*2;
 
-	//CONS_Printf("langing on slope\n");
+	//CONS_Printf("Landing on slope\n");
 
 	// Reverse quantizing might could use its own function later
 	slope->zangle = ANGLE_MAX-slope->zangle;
@@ -871,16 +871,10 @@ void P_ButteredSlope(mobj_t *mo)
 		thrust = FixedMul(thrust, FRACUNIT+P_AproxDistance(mo->momx, mo->momy)/16);
 	// This makes it harder to zigzag up steep slopes, as well as allows greater top speed when rolling down
 
-	// The strength of gravity depends on the global gravity base setting...
-	thrust = FixedMul(thrust, gravity);
-
-	// ...the sector-based gravity strength...
+	// Let's get the gravity strength for the object...
 	thrust = FixedMul(thrust, abs(P_GetMobjGravity(mo)));
 
-	// ...and the scale of the object.
-	thrust = FixedMul(thrust, mo->scale);
-
-	// Let's also multiply by friction for good measure.
+	// ... and its friction against the ground for good measure.
 	thrust = FixedMul(thrust, mo->friction);
 
 	P_Thrust(mo, mo->standingslope->xydirection, thrust);