Merge branch 'skybox-improvements' into 'master'

Skybox improvements

Some improvements to skyboxes and new features for them:

* *The Thing's Z position now determines the relative z position of a skybox viewpoint from the ground, the Thing's angle no longer affects the Z position at all.* This should also fix objectplace breaking skyboxes after you place a Thing, and allow Z heights to be more easily controlled by custom skybox mobjs set by Lua's `P_SetSkyboxMobj`.
* The skybox viewpoint Thing's "Parameter" value (or the multiple of 4096 added to the Thing type, if you're still using SRB2DB) determines the ID number for a viewpoint or centerpoint, a value between 0 and 15. By default the game uses the viewpoint and centerpoint using ID 0. Note: this ID system does not apply to custom skybox mobjs set by Lua, only to `MT_SKYBOX` mobjs spawned by Things for a map.
* **Linedef type 448** has been added as a linedef executor special for changing the skybox viewpoint and/or centerpoint used, making use of the new ID system mentioned above:
 * By default, only the *viewpoint* will be changed. The front x offsets set the ID of the new viewpoint to use; if the number is out of range (numbers accepted are 0 to 15), the game will simply not use any viewpoint at all.
 * If the "*Block Enemies*" flag is set, the centerpoint will be changed as well. In this case the front y offsets set the new centerpoint ID to use.
 * If the "*Solid Midtexture*" flag is set, the viewpoint will **not** be changed at all. Combine this with Block Enemies to make the linedef type change only the centerpoint if needed (otherwise the linedef will do nothing lol).
 * By default, only the player who triggered the linedef will see the skybox being changed. If a player did not trigger the linedef executor directly, no change will be seen by anyone. If the "*Not Climbable*" flag is set, the skybox change will be "global", i.e. it will be seen by all players in the map.

In my folder on the FTP I've made a subfolder called "skybox improvements", and in it are the following files:
* srb2win-skyboximprov.exe - the test exe for this branch I've compiled myself
* skyboxchange-test.wad - an edit of my test map for my skybox change Lua script release on the MB, to test out the new skybox change linedef type.

See merge request !89

src/p_mobj.c

@@ -9717,11 +9717,10 @@ void P_SpawnMapThing(mapthing_t *mthing)
 	switch(mobj->type)
 	{
 	case MT_SKYBOX:
-		mobj->angle = 0;
 		if (mthing->options & MTF_OBJECTSPECIAL)
-			skyboxmo[1] = mobj;
+			skyboxcenterpnts[mthing->extrainfo] = mobj;
 		else
-			skyboxmo[0] = mobj;
+			skyboxviewpnts[mthing->extrainfo] = mobj;
 		break;
 	case MT_FAN:
 		if (mthing->options & MTF_OBJECTSPECIAL)

src/p_setup.c

@@ -2276,6 +2276,17 @@ void P_LoadThingsOnly(void)
 	// Search through all the thinkers.
 	mobj_t *mo;
 	thinker_t *think;
+	INT32 i, viewid = -1, centerid = -1; // for skyboxes
+
+	// check if these are any of the normal viewpoint/centerpoint mobjs in the level or not
+	if (skyboxmo[0] || skyboxmo[1])
+		for (i = 0; i < 16; i++)
+		{
+			if (skyboxmo[0] && skyboxmo[0] == skyboxviewpnts[i])
+				viewid = i; // save id just in case
+			if (skyboxmo[1] && skyboxmo[1] == skyboxcenterpnts[i])
+				centerid = i; // save id just in case
+		}
 
 	for (think = thinkercap.next; think != &thinkercap; think = think->next)
 	{
@@ -2293,6 +2304,10 @@ void P_LoadThingsOnly(void)
 	P_PrepareThings(lastloadedmaplumpnum + ML_THINGS);
 	P_LoadThings();
 
+	// restore skybox viewpoint/centerpoint if necessary, set them to defaults if we can't do that
+	skyboxmo[0] = skyboxviewpnts[(viewid >= 0) ? viewid : 0];
+	skyboxmo[1] = skyboxcenterpnts[(centerid >= 0) ? centerid : 0];
+
 	P_SpawnSecretItems(true);
 }
 
@@ -2728,6 +2743,9 @@ boolean P_SetupLevel(boolean skipprecip)
 	for (i = 0; i < 2; i++)
 		skyboxmo[i] = NULL;
 
+	for (i = 0; i < 16; i++)
+		skyboxviewpnts[i] = skyboxcenterpnts[i] = NULL;
+
 	P_MapStart();
 
 	P_PrepareThings(lastloadedmaplumpnum + ML_THINGS);
@@ -2737,6 +2755,9 @@ boolean P_SetupLevel(boolean skipprecip)
 #endif
 
 	P_LoadThings();
+	// skybox mobj defaults
+	skyboxmo[0] = skyboxviewpnts[0];
+	skyboxmo[1] = skyboxcenterpnts[0];
 
 	P_SpawnSecretItems(loademblems);
 

src/p_spec.c

@@ -46,7 +46,9 @@
 #include <errno.h>
 #endif
 
-mobj_t *skyboxmo[2];
+mobj_t *skyboxmo[2]; // current skybox mobjs: 0 = viewpoint, 1 = centerpoint
+mobj_t *skyboxviewpnts[16]; // array of MT_SKYBOX viewpoint mobjs
+mobj_t *skyboxcenterpnts[16]; // array of MT_SKYBOX centerpoint mobjs
 
 // Amount (dx, dy) vector linedef is shifted right to get scroll amount
 #define SCROLL_SHIFT 5
@@ -3159,6 +3161,47 @@ static void P_ProcessLineSpecial(line_t *line, mobj_t *mo, sector_t *callsec)
 			}
 			break;
 
+		case 448: // Change skybox viewpoint/centerpoint
+			if ((mo && mo->player && P_IsLocalPlayer(mo->player)) || (line->flags & ML_NOCLIMB))
+			{
+				INT32 viewid = sides[line->sidenum[0]].textureoffset>>FRACBITS;
+				INT32 centerid = sides[line->sidenum[0]].rowoffset>>FRACBITS;
+
+				if ((line->flags & (ML_EFFECT4|ML_BLOCKMONSTERS)) == ML_EFFECT4) // Solid Midtexture is on but Block Enemies is off?
+				{
+					CONS_Alert(CONS_WARNING,
+					M_GetText("Skybox switch linedef (tag %d) doesn't have anything to do.\nConsider changing the linedef's flag configuration or removing it entirely.\n"),
+					line->tag);
+				}
+				else
+				{
+					// set viewpoint mobj
+					if (!(line->flags & ML_EFFECT4)) // Solid Midtexture turns off viewpoint setting
+					{
+						if (viewid >= 0 && viewid < 16)
+							skyboxmo[0] = skyboxviewpnts[viewid];
+						else
+							skyboxmo[0] = NULL;
+					}
+
+					// set centerpoint mobj
+					if (line->flags & ML_BLOCKMONSTERS) // Block Enemies turns ON centerpoint setting
+					{
+						if (centerid >= 0 && centerid < 16)
+							skyboxmo[1] = skyboxcenterpnts[centerid];
+						else
+							skyboxmo[1] = NULL;
+					}
+				}
+
+				CONS_Debug(DBG_GAMELOGIC, "Line type 448 Executor: viewid = %d, centerid = %d, viewpoint? = %s, centerpoint? = %s\n",
+						viewid,
+						centerid,
+						((line->flags & ML_EFFECT4) ? "no" : "yes"),
+						((line->flags & ML_BLOCKMONSTERS) ? "yes" : "no"));
+			}
+			break;
+
 		case 450: // Execute Linedef Executor - for recursion
 			P_LinedefExecute(line->tag, mo, NULL);
 			break;

src/p_spec.h

@@ -17,7 +17,9 @@
 #ifndef __P_SPEC__
 #define __P_SPEC__
 
-extern mobj_t *skyboxmo[2];
+extern mobj_t *skyboxmo[2]; // current skybox mobjs: 0 = viewpoint, 1 = centerpoint
+extern mobj_t *skyboxviewpnts[16]; // array of MT_SKYBOX viewpoint mobjs
+extern mobj_t *skyboxcenterpnts[16]; // array of MT_SKYBOX centerpoint mobjs
 
 // GETSECSPECIAL (specialval, section)
 //

src/r_main.c

@@ -798,9 +798,7 @@ void R_SkyboxFrame(player_t *player)
 
 	viewx = viewmobj->x;
 	viewy = viewmobj->y;
-	viewz = 0;
-	if (viewmobj->spawnpoint)
-		viewz = ((fixed_t)viewmobj->spawnpoint->angle)<<FRACBITS;
+	viewz = viewmobj->z; // 26/04/17: use actual Z position instead of spawnpoint angle!
 
 	if (mapheaderinfo[gamemap-1])
 	{