Fix object sloperoll issues

src/p_user.c

@@ -3884,8 +3884,8 @@ static angle_t P_GetCameraPitchRollAngle(mobj_t *mobj, player_t *viewPlayer)
 	}
 	else
 	{
-		// Regular Mobjs don't air tilt.
-		viewingAngle = mobj->angle;
+		// For regular objects, use the camera; just not the *player's* camera.
+		viewingAngle = R_PointToAngleFloat(mobj->x, mobj->y);
 	}
 
 	pitchMul = -FINESINE(viewingAngle >> ANGLETOFINESHIFT);

src/r_main.cpp

@@ -14,6 +14,7 @@
 ///        See tables.c, too.
 
 #include <algorithm>
+#include <cmath>
 
 #include "doomdef.h"
 #include "g_game.h"
@@ -51,6 +52,9 @@ extern consvar_t cv_debugrender_freezebsp;
 // Fineangles in the SCREENWIDTH wide window.
 #define FIELDOFVIEW 2048
 
+// Double-precision Pi value
+#define DOUBLE_PI 3.141592653589793
+
 // increment every time a check is made
 size_t validcount = 1;
 
@@ -387,6 +391,29 @@ angle_t R_PointToAngle2(fixed_t pviewx, fixed_t pviewy, fixed_t x, fixed_t y)
 		0;
 }
 
+#define ANGLE_180_DOUBLE (static_cast<double>(ANGLE_180))
+#define ANGLE_360_DOUBLE (ANGLE_180_DOUBLE * 2)
+
+// For absolute accuracy. Please don't use this outside of renderers.
+angle_t R_PointToAngleFloat2(fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2)
+{
+	double deltax = FixedToDouble(x2 - x1);
+	double deltay = FixedToDouble(y2 - y1);
+
+	// Converted to degrees
+	double _arctan = (atan2(deltay, deltax) * ANGLE_180_DOUBLE) / DOUBLE_PI;
+
+	while (_arctan < 0)
+	{
+		_arctan += ANGLE_360_DOUBLE;
+	}
+
+	return static_cast<angle_t>(_arctan);
+}
+
+#undef ANGLE_180_DOUBLE
+#undef ANGLE_360_DOUBLE
+
 //
 // R_ScaleFromGlobalAngle
 // Returns the texture mapping scale for the current line (horizontal span)

src/r_main.h

@@ -83,9 +83,11 @@ FUNCINLINE static ATTRINLINE INT32 R_PointOnSideFast(fixed_t x, fixed_t y, const
 
 INT32 R_PointOnSegSide(fixed_t x, fixed_t y, const seg_t *line);
 #define R_PointToAngle(x, y) R_PointToAngle2(viewx, viewy, x, y)
+#define R_PointToAngleFloat(x, y) (R_PointToAngleFloat2(viewx, viewy, x, y))
 angle_t R_PointToAnglePlayer(player_t *player, fixed_t x, fixed_t y);
 angle_t R_PointToAngle64(INT64 x, INT64 y);
 angle_t R_PointToAngle2(fixed_t px2, fixed_t py2, fixed_t px1, fixed_t py1);
+angle_t R_PointToAngleFloat2(fixed_t x1, fixed_t y1, fixed_t x2, fixed_t y2);
 #define R_PointToDist(x, y) R_PointToDist2(viewx, viewy, x, y)
 #define R_PointToDist2(px2, py2, px1, py1) FixedHypot((px1) - (px2), (py1) - (py2))
 

src/r_patchrotation.c

@@ -38,8 +38,8 @@ angle_t R_GetPitchRollAngle(mobj_t *mobj, player_t *viewPlayer, interpmobjstate_
 	}
 	else
 	{
-		// Regular Mobjs don't air tilt.
-		viewingAngle = mobj->angle;
+		// For regular objects, use the camera; just not the *player's* camera.
+		viewingAngle = R_PointToAngleFloat(mobj->x, mobj->y);
 	}
 
 	pitchMul = -FINESINE(viewingAngle >> ANGLETOFINESHIFT);