From 9f82cdb4010cd38994cfc09e5b75212085050230 Mon Sep 17 00:00:00 2001
From: Zachary McAlpin <choalover@gmail.com>
Date: Thu, 19 Dec 2019 16:41:25 -0600
Subject: [PATCH] Added CalculateCamera Hook

---
 src/lua_hook.h    |  2 ++
 src/lua_hooklib.c | 41 +++++++++++++++++++++++++++++++++++++++++
 src/p_user.c      | 33 ++++++++++++++++++++-------------
 3 files changed, 63 insertions(+), 13 deletions(-)

diff --git a/src/lua_hook.h b/src/lua_hook.h
index 073773f52..4b31fda28 100644
--- a/src/lua_hook.h
+++ b/src/lua_hook.h
@@ -52,6 +52,7 @@ enum hook {
 	hook_PlayerQuit,
 	hook_IntermissionThinker,
 	hook_PlayerThink,
+	hook_CalculateCamera,
 
 	hook_MAX // last hook
 };
@@ -95,5 +96,6 @@ UINT8 LUAh_PlayerCanDamage(player_t *player, mobj_t *mobj); // Hook for P_Player
 void LUAh_PlayerQuit(player_t *plr, int reason); // Hook for player quitting
 void LUAh_IntermissionThinker(void); // Hook for Y_Ticker
 #define LUAh_PlayerThink(player) LUAh_PlayerHook(player, hook_PlayerThink) // Hook for P_PlayerThink
+boolean LUAh_CalculateCamera(player_t *player, camera_t *camera); // Hook for P_PlayerAfterThink Camera calculations
 
 #endif
diff --git a/src/lua_hooklib.c b/src/lua_hooklib.c
index 30ab27da1..b7e544ed0 100644
--- a/src/lua_hooklib.c
+++ b/src/lua_hooklib.c
@@ -63,6 +63,7 @@ const char *const hookNames[hook_MAX+1] = {
 	"PlayerQuit",
 	"IntermissionThinker",
 	"PlayerThink",
+	"CalculateCamera",
 	NULL
 };
 
@@ -207,6 +208,7 @@ static int lib_addHook(lua_State *L)
 	case hook_ShieldSpawn:
 	case hook_ShieldSpecial:
 	case hook_PlayerThink:
+	case hook_CalculateCamera:
 		lastp = &playerhooks;
 		break;
 	case hook_LinedefExecute:
@@ -1348,4 +1350,43 @@ void LUAh_IntermissionThinker(void)
 	}
 }
 
+boolean LUAh_CalculateCamera(player_t *player, camera_t *camera)
+{
+	hook_p hookp;
+	boolean hooked;
+	if (!gL || !(hooksAvailable[hook_CalculateCamera/8] & (1<<(hook_CalculateCamera%8))))
+		return 0;
+	
+	lua_settop(gL, 0);
+	
+	for (hookp = playerhooks; hookp; hookp = hookp->next)
+	{
+		if (hookp->type != hook_CalculateCamera)
+			continue;
+		
+		if (lua_gettop(gL) == 0)
+		{
+			LUA_PushUserdata(gL, player, META_PLAYER);
+			LUA_PushUserdata(gL, camera, META_CAMERA);
+		}
+		lua_pushfstring(gL, FMT_HOOKID, hookp->id);
+		lua_gettable(gL, LUA_REGISTRYINDEX);
+		lua_pushvalue(gL, -3);
+		lua_pushvalue(gL, -3);
+		if (lua_pcall(gL, 2, 1, 0)) {
+			if (!hookp->error || cv_debug & DBG_LUA)
+				CONS_Alert(CONS_WARNING,"%s\n",lua_tostring(gL, -1));
+			lua_pop(gL, 1);
+			hookp->error = true;
+			continue;
+		}
+		if (lua_toboolean(gL, -1))
+			hooked = true;
+		lua_pop(gL, 1);
+	}
+	
+	lua_settop(gL, 0);
+	return hooked;
+}
+
 #endif
diff --git a/src/p_user.c b/src/p_user.c
index 3baf8cd04..6eedec10f 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -12626,22 +12626,29 @@ void P_PlayerAfterThink(player_t *player)
 
 	if (thiscam)
 	{
-		if (!thiscam->chase) // bob view only if looking through the player's eyes
-		{
-			P_CalcHeight(player);
-			P_CalcPostImg(player);
-		}
+#ifdef HAVE_BLUA
+		if (LUAh_CalculateCamera(player, thiscam))
+			{;}
 		else
+#endif
 		{
-			// defaults to make sure 1st person cam doesn't do anything weird on startup
-			player->deltaviewheight = 0;
-			player->viewheight = FixedMul(41*player->height/48, player->mo->scale);
-			if (player->mo->eflags & MFE_VERTICALFLIP)
-				player->viewz = player->mo->z + player->mo->height - player->viewheight;
+			if (!thiscam->chase) // bob view only if looking through the player's eyes
+			{
+				P_CalcHeight(player);
+				P_CalcPostImg(player);
+			}
 			else
-				player->viewz = player->mo->z + player->viewheight;
-			if (server || addedtogame)
-				P_MoveChaseCamera(player, thiscam, false); // calculate the camera movement
+			{
+				// defaults to make sure 1st person cam doesn't do anything weird on startup
+				player->deltaviewheight = 0;
+				player->viewheight = FixedMul(41*player->height/48, player->mo->scale);
+				if (player->mo->eflags & MFE_VERTICALFLIP)
+					player->viewz = player->mo->z + player->mo->height - player->viewheight;
+				else
+					player->viewz = player->mo->z + player->viewheight;
+				if (server || addedtogame)
+					P_MoveChaseCamera(player, thiscam, false); // calculate the camera movement
+			}
 		}
 	}