Tutorial: spellcasting

Add some basic spellcasting stuff to the tutorial: read a spellbook,
cast a spell.  If the hero doesn't have enough energy, just adds
a note saying so.

Remove/restore the known spells when entering/leaving the tutorial.

dat/tut-1.lua

@@ -32,10 +32,10 @@ des.level_flags("mazelevel", "noflip",
 
 des.map([[
 ---------------------------------------------------------------------------
-|-.--|.......|......|..S....|.F.......|.............|.....................|
+|-.--|.......|......|..S....|.F.......|.............|.......|.............|
 |.-..........|......|--|....|.F.....|.|S-------.....|.....................|
-||.--|.......|..T......|....|.F.....|.|.......|.....|.....................|
-||.|.|.......|......|-.|....|.F.....|.|.......|.....|.....................|
+||.--|.......|..T......|....|.F.....|.|.......|.....|.......|.............|
+||.|.|.......|......|-.|....|.F.....|.|.......|.....|--------.............|
 ||.|.|.......|......||.|-.-----------.-.......|-S----.....................|
 |-+-S---------..---.||........................|...|.......................|
 |......|          |.-------------------.......|...|....--S----............|
@@ -302,6 +302,21 @@ des.object({ id = "boulder", coord = {72,16} });
 des.object({ id = "boulder", coord = {73,16} });
 des.trap({ type = "trap door", coord = { 73,15 } });
 
+--
+
+des.engraving({ coord = { 60,2 }, type = "engrave", text = "Spellcasting", degrade = false });
+if (u.uenmax < 5) then
+   -- TODO: make sure hero has enough Pw to cast the spell (5 pw) instead?
+   -- TODO: ensure the first cast of this spell succeeds?
+   des.engraving({ coord = { 59,2 }, type = "engrave", text = "Unfortunately you don't have enough energy to cast spells.", degrade = false });
+end
+des.engraving({ coord = { 57,2 }, type = "engrave", text = "Pick up the spellbook with '" .. tut_key("pickup") .. "'", degrade = false });
+des.object({ coord = { 57,2 }, id = "spellbook of light", buc = "blessed" });
+des.engraving({ coord = { 55,2 }, type = "engrave", text = "Read the spellbook with '" .. tut_key("read") .. "'", degrade = false });
+des.engraving({ coord = { 53,2 }, type = "engrave", text = "Use '" .. tut_key("cast") .. "' to cast a spell", degrade = false });
+des.region(selection.area(53,01, 59, 3), "unlit");
+
+
 ----------------
 
 -- entering and leaving tutorial _branch_ now handled by core

include/decl.h

@@ -423,6 +423,7 @@ struct instance_globals_g {
     long gmst_moves;
     struct obj *gmst_invent;
     genericptr_t *gmst_ubak, *gmst_disco, *gmst_mvitals;
+    struct spell gmst_spl_book[MAXSPELL + 1];
 
     /* pline.c */
     struct gamelog_line *gamelog;

src/decl.c

@@ -372,6 +372,7 @@ static const struct instance_globals_g g_init_g = {
     0L, /* gmst_moves */
     NULL, /* gmst_invent */
     NULL, NULL, NULL, /* gmst_ubak, gmst_disco, gmst_mvitals */
+    { DUMMY }, /* gmst_spl_book */
     /* pline.c */
     UNDEFINED_PTR, /* gamelog */
     /* region.c */

src/nhlua.c

@@ -1695,6 +1695,7 @@ nhl_gamestate(lua_State *L)
         init_uhunger();
         free_tutorial(); /* release gg.gmst_XYZ */
         gg.gmst_stored = FALSE;
+        (void) memcpy(svs.spl_book, gg.gmst_spl_book, sizeof svs.spl_book);
     } else if (!reststate && !gg.gmst_stored) {
         /* store game state */
         gg.gmst_moves = svm.moves;
@@ -1715,6 +1716,8 @@ nhl_gamestate(lua_State *L)
         gg.gmst_mvitals = (genericptr_t) alloc(sizeof svm.mvitals);
         (void) memcpy(gg.gmst_mvitals, (genericptr_t) &svm.mvitals,
                       sizeof svm.mvitals);
+        (void) memcpy(gg.gmst_spl_book, svs.spl_book, sizeof svs.spl_book);
+        (void) memset(svs.spl_book, 0, sizeof(svs.spl_book));
         gg.gmst_stored = TRUE;
     } else {
         impossible("nhl_gamestate: inconsistent state (%s vs %s)",