From f72aa63f363554e76e8a4240e7e529b3e9f5201e Mon Sep 17 00:00:00 2001
From: James R <justsomejames2@gmail.com>
Date: Mon, 14 Aug 2023 01:00:11 -0700
Subject: [PATCH] Interpolate view, even when paused

Fixes slideshow movement with demo freecam while paused.
Does not appear to jitter like texture scrollers do.
---
 src/d_main.cpp | 3 +++
 src/r_main.cpp | 3 ++-
 src/r_main.h   | 2 ++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/d_main.cpp b/src/d_main.cpp
index 0fc9f36f1..8133900b8 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -907,11 +907,14 @@ void D_SRB2Loop(void)
 			{
 				rendertimefrac = FRACUNIT;
 			}
+
+			rendertimefrac_unpaused = g_time.timefrac;
 		}
 		else
 		{
 			renderdeltatics = realtics * FRACUNIT;
 			rendertimefrac = FRACUNIT;
+			rendertimefrac_unpaused = FRACUNIT;
 		}
 
 		if ((interp || doDisplay) && !frameskip)
diff --git a/src/r_main.cpp b/src/r_main.cpp
index 8adb6ab5e..867cc950d 100644
--- a/src/r_main.cpp
+++ b/src/r_main.cpp
@@ -89,6 +89,7 @@ mobj_t *r_viewmobj;
 int r_splitscreen;
 
 fixed_t rendertimefrac;
+fixed_t rendertimefrac_unpaused;
 fixed_t renderdeltatics;
 boolean renderisnewtic;
 
@@ -1215,7 +1216,7 @@ R_SetupCommonFrame
 	else
 		newview->sector = R_PointInSubsector(newview->x, newview->y)->sector;
 
-	R_InterpolateView(rendertimefrac);
+	R_InterpolateView(rendertimefrac_unpaused);
 }
 
 static void R_SetupAimingFrame(int s)
diff --git a/src/r_main.h b/src/r_main.h
index 762095bff..c3dd7a5b4 100644
--- a/src/r_main.h
+++ b/src/r_main.h
@@ -39,6 +39,8 @@ extern size_t validcount, linecount, loopcount, framecount;
 
 // The fraction of a tic being drawn (for interpolation between two tics)
 extern fixed_t rendertimefrac;
+// Same as rendertimefrac but not suspended when the game is paused
+extern fixed_t rendertimefrac_unpaused;
 // Evaluated delta tics for this frame (how many tics since the last frame)
 extern fixed_t renderdeltatics;
 // The current render is a new logical tic