From 4c9569c2544a8464bf542190a323a2487b66cde3 Mon Sep 17 00:00:00 2001
From: Shpoike <Shpoike@users.noreply.github.com>
Date: Wed, 24 Jun 2020 02:57:44 +0100
Subject: [PATCH] Try to make IQM animations sync to when the frame is changed
 (like FTE or DP) so that the animations can actually be used for non-static
 things. There are still no 4-way blends, however.

---
 Quake/cl_parse.c | 9 ++++++---
 Quake/gl_mesh.c  | 1 +
 Quake/gl_model.h | 2 +-
 Quake/modelgen.h | 2 +-
 Quake/r_alias.c  | 7 +++++--
 5 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/Quake/cl_parse.c b/Quake/cl_parse.c
index 99f788de..57303a10 100644
--- a/Quake/cl_parse.c
+++ b/Quake/cl_parse.c
@@ -554,8 +554,6 @@ static void CL_EntitiesDeltaed(void)
 
 		ent->msgtime = cl.mtime[0];
 
-		ent->frame = ent->netstate.frame;
-
 		i = ent->netstate.colormap;
 		if (!i)
 			ent->colormap = vid.colormap;
@@ -611,7 +609,9 @@ static void CL_EntitiesDeltaed(void)
 		// or randomized
 			if (model)
 			{
-				if (model->synctype == ST_RAND)
+				if (model->synctype == ST_FRAMETIME)
+					ent->syncbase = -cl.time;
+				else if (model->synctype == ST_RAND)
 					ent->syncbase = (float)(rand()&0x7fff) / 0x7fff;
 				else
 					ent->syncbase = 0.0;
@@ -623,6 +623,9 @@ static void CL_EntitiesDeltaed(void)
 
 			ent->lerpflags |= LERP_RESETANIM; //johnfitz -- don't lerp animation across model changes
 		}
+		else if (model && model->synctype == ST_FRAMETIME && ent->frame != ent->netstate.frame)
+			ent->syncbase = -cl.time;
+		ent->frame = ent->netstate.frame;
 
 		if ( forcelink )
 		{	// didn't have an update last message
diff --git a/Quake/gl_mesh.c b/Quake/gl_mesh.c
index 58981db7..06ea77b7 100644
--- a/Quake/gl_mesh.c
+++ b/Quake/gl_mesh.c
@@ -1285,6 +1285,7 @@ void Mod_LoadIQMModel (qmodel_t *mod, const void *buffer)
 	mod->flags = LittleLong (pinheader->flags);
 
 
+	mod->synctype = ST_FRAMETIME;	//keep IQM animations synced to when .frame is changed. framegroups are otherwise not very useful.
 	mod->type = mod_alias;
 
 	Mod_CalcAliasBounds (outhdr); //johnfitz
diff --git a/Quake/gl_model.h b/Quake/gl_model.h
index 312143c0..992d1207 100644
--- a/Quake/gl_model.h
+++ b/Quake/gl_model.h
@@ -357,7 +357,7 @@ typedef struct {
 	int			numverts;
 	int			numtris;
 	int			numframes;
-	synctype_t	synctype;
+//	synctype_t	synctype;
 	int			flags;
 	float		size;
 
diff --git a/Quake/modelgen.h b/Quake/modelgen.h
index 92dbcf4c..dbba7bd3 100644
--- a/Quake/modelgen.h
+++ b/Quake/modelgen.h
@@ -54,7 +54,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 // must match definition in spritegn.h
 #ifndef SYNCTYPE_T
 #define SYNCTYPE_T
-typedef enum {ST_SYNC=0, ST_RAND } synctype_t;
+typedef enum {ST_SYNC=0, ST_RAND, ST_FRAMETIME/*sync to when .frame changes*/ } synctype_t;
 #endif
 
 typedef enum { ALIAS_SINGLE=0, ALIAS_GROUP } aliasframetype_t;
diff --git a/Quake/r_alias.c b/Quake/r_alias.c
index 121bc55b..1f4e1367 100644
--- a/Quake/r_alias.c
+++ b/Quake/r_alias.c
@@ -746,8 +746,11 @@ void R_SetupAliasFrame (aliashdr_t *paliashdr, int frame, lerpdata_t *lerpdata)
 
 	if (numposes > 1)
 	{
-		e->lerptime = paliashdr->frames[frame].interval;
-		posenum += (int)(cl.time / e->lerptime) % numposes;
+		float time = cl.time + e->syncbase;	//Spike: Readded syncbase
+		if (time < 0)
+			time = 0;	//just in case...
+		e->lerptime = paliashdr->frames[frame].interval;	//FIXME: no per-frame intervals
+		posenum += (int)(time / e->lerptime) % numposes;
 	}
 	else
 		e->lerptime = 0.1;