Pass RETURN to EVENT_DAMAGEHPLANE in the 'dist' arg to allow chained callbacks.

git-svn-id: https://svn.eduke32.com/eduke32@4208 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/source/lunatic/doc/lunatic.txt

@@ -2242,19 +2242,27 @@ cheat give a different ``full'' amount. A negative value is ignored.
 ~~~~~~~~~~~~~~~~~~~~
 
 Triggered when a ceiling or a floor (collectively called ``hplane'') is
-determined as being damaged. The event receives `RETURN` as a value that can be
-decoded into two parts by passing it to `sector.damagehplane_whatsect`:
+determined as being damaged. The event receives `RETURN` in the variable
+`gv.RETURN` as well as the third, `dist` argument to the event
+<<gameactor,callback function>>.footnote:[Passing `RETURN` in the `dist`
+argument serves the possibility to create chained callbacks for
+`EVENT_DAMAGEHPLANE`. Otherwise, once `gv.RETURN` were assigned to, there would
+be no way to obtain its original value in subsequent chained callbacks.] This
+value can be decoded into two parts by passing it to
+`sector.damagehplane_whatsect`:
 
 [source]
 ----------
-local what, sectnum = sector.damagehplane_whatsect(gv.RETURN)
+function(aci, pli, RETURN)
+   local what, sectnum = sector.damagehplane_whatsect(RETURN)
+   -- (...)
 ----------
 Then,
 
 * `what` is one of the strings `'ceiling'` or `'floor'` and
 * `sectnum` is the sector whose hplane is considered to be damaged.
 
-When `EVENT_DAMAGEHPLANE` is left, `RETURN` is examined to determine the
+When `EVENT_DAMAGEHPLANE` is left, `gv.RETURN` is examined to determine the
 further action. It may be one of three values given by `sector.DAMAGEHPLANE`
 (abbreviated `DHP` in the following):
 

polymer/eduke32/source/lunatic/test/damagehplane.lua

@@ -59,10 +59,10 @@ local DHP = sector.DAMAGEHPLANE
 
 gameevent
 {
-    gv.EVENT_DAMAGEHPLANE,
+    "DAMAGEHPLANE",
 
-    function(aci, pli, dist)
-        local what, sectnum = sector.damagehplane_whatsect(gv.RETURN)
+    function(aci, pli, RETURN)
+        local what, sectnum = sector.damagehplane_whatsect(RETURN)
         local sec = sector[sectnum]
 
         -- Part I: make various screens breakable when it's a ceiling picnum.
@@ -71,10 +71,22 @@ gameevent
             if (sec.ceilingpicnum >= 263 and sec.ceilingpicnum <= 275) then
                 sec:set_ceilingpicnum(D.W_SCREENBREAK + gv.krand()%3)
                 gv.RETURN = DHP.GLASSBREAK
-                return
+                return con.longjmp()
             end
         end
 
+        gv.RETURN = DHP.DEFAULT
+    end
+}
+
+gameevent
+{
+    "DAMAGEHPLANE",
+
+    function(aci, pli, RETURN)
+        local what, sectnum = sector.damagehplane_whatsect(RETURN)
+        local sec = sector[sectnum]
+
         -- Part II: breakable TROR hplanes
         local cf = sec[what]
 --        printf("damage %s of sector %d (pic %d, bunch %d, hittable: %s)", what, sectnum,
@@ -90,7 +102,7 @@ gameevent
             breaker.extra = cf.bunch
 
             gv.RETURN = DHP.SUPPRESS
-            return
+            return con.longjmp()
         end
 
         gv.RETURN = DHP.DEFAULT

polymer/eduke32/source/sector.c

@@ -1880,7 +1880,9 @@ int32_t Sect_DamageCeilingOrFloor(int32_t floorp, int32_t sn)
     int32_t i, j;
 
     const int32_t RETURN_in = floorp ? 131072+sn : 65536+sn;
-    int32_t ret = VM_OnEvent(EVENT_DAMAGEHPLANE, g_player[screenpeek].ps->i, screenpeek, -1, RETURN_in);
+    // NOTE: pass RETURN in the dist argument, too.
+    int32_t ret = VM_OnEvent(EVENT_DAMAGEHPLANE, g_player[screenpeek].ps->i, screenpeek,
+                             RETURN_in, RETURN_in);
 
     if (ret < 0)
         return 0;