Fix Launch Octopus co-op interactions and charged-shot graphics

docs/coop-port.md

@@ -984,3 +984,35 @@ with the project flags and the policy test passes). To confirm: die to the
 mid-boss in the stage, take the checkpoint, and walk to its room; it should
 spawn on the way in, solo and in co-op. `SNESRECOMP_WS_SPAWN=0` (authentic
 4:3 spawn timing) is the fallback on builds without this change.
+
+### Launch Octopus player interactions
+
+Gulpfer (`$1D`, `$82:A341`) chooses the nearest eligible living player while
+free. A player already hidden or frozen inside another fish is ineligible.
+During capture, hold, escape and death, the fish retains its victim in the
+native-unused `.3F` byte (seat plus one). This keeps release and motion tied
+to the captured body even as the other player approaches. Older snapshots
+without `.3F` recover ownership from the parked body. This applies in unified
+and independent camera modes and survives ordinary snapshots and rollback.
+
+The tall water vortex is effect `$16` (`$81:F493`), separate from enemy `$28`'s
+upward currents. Its `$00:D359..D35C` update receives a speculative second
+body pass, keeping that body's contact, action and motion while restoring
+world state. The real pass advances animation, timers and bubbles once.
+Shotgun Ice sled replays now keep BD4 as well as BD3: dropping its newly
+written landing flag let the partner ride with a falling animation.
+
+Charged-buster CHR isolation covers native projectile kinds `$01/$02/$03`.
+Kind `$01` was omitted from the earlier renderer repair. Group `$0E` pose 6
+retains tile `$31` from pose 4/5 because its short bottom-row DMA replaces
+only tile `$30`; the isolated ROM asset must retain that same tile.
+
+`MMX_COOP_OCTOPUS_TEST=<private-directory>` runs focused ROM checks using
+`save3.sav` (fish) and `save6.sav` (vortex). It covers both character assignments,
+returned players, separate captures and release, both world actors, vortex
+entry/exit, standing and riding the ice sled, simultaneous native charged
+busters, the retained ROM tile, and deterministic snapshot replay. Set
+`MMX_COOP_ONLINE_FIXTURE=1` to exercise the fish and vortex in independent
+camera paths without opening sockets or a lobby. Synthetic projectile
+placement uses the unified view; independent views can cull that imposed
+ice-sled fixture before landing. Fixtures and source ROM assets remain private.

src/mmx_coop.c

@@ -1395,7 +1395,7 @@ static void pickup_hook(CpuState *cpu,uint32_t pc) {
  * weapon combat, Zero and co-op state, renderer pieces), so every object
  * still advances once. Couch co-op only for objects: online views already
  * project the nearest player for AI. */
-enum { GHOST_SHOTS=1, GHOST_OBJECT };
+enum { GHOST_SHOTS=1, GHOST_OBJECT, GHOST_CURRENT };
 static struct {
   uint8_t pass,kind,p,db;uint16_t a,x,y,s,d;uint32_t resume;
   uint8_t body[0x90];
@@ -1414,9 +1414,11 @@ static bool ghost_active(void) { return shot_ghost.pass==1; }
  * Octopus's current generator ($28) only flags a body it finds in one of its
  * four $82:D7D7 boxes (.3C, action $08); the player's own movement lifts it.
  * Contact damage taken during the replay is kept too, and the real update's
- * contact retry then finds the partner already hit and invulnerable. */
+ * contact retry then finds the partner already hit and invulnerable.
+ * Shot riders also need BD4 (.2C), not just last frame's BD3 (.2B): the
+ * native landing controller consumes that flag on the following frame. */
 static bool shot_ghost_field(unsigned i) {
-  return shot_ghost.kind==GHOST_OBJECT || (i>=4 && i<=9) || (i>=0x1a && i<=0x1d) || i==0x2b;
+  return shot_ghost.kind!=GHOST_SHOTS || (i>=4 && i<=9) || (i>=0x1a && i<=0x1d) || i==0x2b || i==0x2c;
 }
 static bool ghost_partner_ready(void) {
   const MmxCoopPlayer *o=&state.players[state.current^1];
@@ -1512,6 +1514,23 @@ static void object_ghost_hook(CpuState *cpu,uint32_t pc) {
     diagnostic_event(g_ram,cpu,pc,"body-moved");
   object_watch.armed=false;
 }
+/* Launch Octopus's vortex is effect $16, not the enemy current generator.
+ * Its native update ($81:F493) clears/sets BE4 and moves only BA8. Replay
+ * the effect for the other living body, retaining its contact and motion,
+ * while the vortex animation, timer and bubbles advance only once. */
+static void current_ghost_hook(CpuState *cpu,uint32_t pc) {
+  if(!enabled || !state.initialized) return;
+  if((pc&65535)==0xd35c) {
+    if(shot_ghost.pass==1 && shot_ghost.kind==GHOST_CURRENT) shot_ghost_end(cpu,pc);
+    return;
+  }
+  if(shot_ghost.pass==2 && shot_ghost.kind==GHOST_CURRENT) {shot_ghost.pass=0;return;}
+  if(shot_ghost.pass || state.menu_owner || state.scene_owner || state.stage_pending ||
+      state.current!=state.anchor || g_ram[0xd3]!=4 || !ghost_partner_ready() ||
+      cpu->D<0x1928 || cpu->D>=0x1d08 || (cpu->D-0x1928)%32 ||
+      !g_ram[cpu->D] || g_ram[cpu->D+10]!=0x16) return;
+  shot_ghost_begin(cpu,GHOST_CURRENT,pc&0xffffff);
+}
 static void object_hook(CpuState *cpu, uint32_t pc) {
   if ((pc&65535)==0xd3f9 && shot_ghost.pass==1 && shot_ghost.kind==GHOST_SHOTS) { shot_ghost_end(cpu,pc); return; }
   if (!enabled || !state.initialized || state.menu_owner || state.scene_owner ||
@@ -1930,6 +1949,9 @@ static void view_actor_hook(CpuState *cpu,uint32_t pc) {
       (at==0xd4f6 || at==0xd515) && couch_nearest_target(cpu->D))) return;
   if(returning) {
     if(world.actor_return) {
+      if(couch_nearest_target(cpu->D) &&
+          (g_ram[cpu->D+0x3b] || g_ram[cpu->D+0x3d]))
+        g_ram[cpu->D+0x3f]=(uint8_t)(state.current+1);
       MmxCoopSelect(g_ram,world.actor_return-1);MmxCoopViewsActorReturn(0);
       select_world_survivor(g_ram);
     }
@@ -1939,10 +1961,26 @@ static void view_actor_hook(CpuState *cpu,uint32_t pc) {
   if(cpu->D<0xe68 || (cpu->D>=0x1228 && cpu->D<0x1428)) return;
   MmxCoopCapture(g_ram);
   unsigned nearest=state.anchor;uint64_t best=UINT64_MAX;
+  bool fish=couch_nearest_target(cpu->D);
+  unsigned owner=fish ? g_ram[cpu->D+0x3f] : 0;
+  bool captured=fish && (g_ram[cpu->D+0x3b] || g_ram[cpu->D+0x3d]);
+  /* Gulpfer's hold/escape/death states act on the body it swallowed, even
+   * when another player moves closer. .3F is unused by its native routine
+   * and travels with the enemy in snapshots and rollback. */
+  if(captured && owner>=1 && owner<=2) {
+    MmxCoopViewsActorReturn(state.current+1);MmxCoopSelect(g_ram,owner-1);return;
+  }
+  if(fish && !captured) g_ram[cpu->D+0x3f]=0;
   int ex=word(g_ram+cpu->D+5),ey=word(g_ram+cpu->D+8);
   for(unsigned seat=0;seat<2;++seat) {
     const MmxCoopPlayer *p=&state.players[seat];
     if(p->status!=MMX_COOP_ALIVE || !(p->body[0x27]&127) || p->body[2]==12 || p->zero.swap_phase) continue;
+    /* A free fish must not chase a body hidden/parked inside another fish.
+     * The native eligibility test would then refuse every swallow attempt. */
+    if(fish && !captured && (!p->body[14] || p->body[0x30])) continue;
+    /* Older snapshots have no .3F owner yet. Recover it from the body
+     * the native capture parked, rather than a nearby uncaptured partner. */
+    if(captured && !owner && p->body[14] && !p->body[0x30]) continue;
     int64_t dx=(int)word(p->body+5)-ex,dy=(int)word(p->body+8)-ey;
     uint64_t distance=(uint64_t)(dx*dx+dy*dy);
     if(distance<best) {best=distance;nearest=seat;}
@@ -1956,6 +1994,8 @@ void MmxCoopRegisterHooks(void) {
   const unsigned ghosts[]={0xd4f6,0xd4f9,0xd499,0xd49c};
   for(unsigned i=0;i<sizeof(ghosts)/sizeof(ghosts[0]);++i)
     interp_bridge_add_pre_opcode_hook(ghosts[i],object_ghost_hook);
+  interp_bridge_add_pre_opcode_hook(0x00d359,current_ghost_hook);
+  interp_bridge_add_pre_opcode_hook(0x00d35c,current_ghost_hook);
   const unsigned views[]={0x00dcd7,0x00dd2d,0x82807d,0x82809e,0x8280c3,0x838957};
   for(unsigned i=0;i<sizeof(views)/sizeof(views[0]);++i)
     interp_bridge_set_pre_opcode_hook(views[i],view_world_hook);

src/mmx_render_assets.c

@@ -94,24 +94,30 @@ const MmxSpriteAsset *MmxRenderAssetsChargedBuster(unsigned group,unsigned pose)
   /* $83:89E3/$8C70 select pose-DMA tables $85:AAF3/$AB9A for groups $0E/$9E. Native
    * $84:8FCA uploads both rows to $6200/$6300. Each pose has different
    * row lengths; a second player's pose can erase the first shot's bottom. */
-  /* Poses 1 and 6 have no transfer; they reuse the preceding growth pose.
-   * The shared disappearance poses 8..10 retain their native live binding. */
+  /* Empty records retain the preceding upload. Pose 6 of group $0E also
+   * replaces only tile $30 of the lower row: its arrangement still reads
+   * tile $31 from pose 4/5. Start with that row before applying the short
+   * transfer, rather than making the bottom-right eight pixels transparent. */
   unsigned upload_pose=kind ? (pose==1 ? 0 : pose==6 ? 5 : pose) :
       pose<4 ? 0 : (pose==17 || pose==18 || pose==20) ? 12 : pose;
   size_t table=kind ? 0x2ab9a : 0x2aaf3;
-  size_t list=table+word(table+upload_pose*2);
   bool complete=false;
-  for (unsigned n=0;n<32;++n,list+=5) {
-    if (!range(list,5)) return NULL;
-    unsigned count=rom[list]*16;
-    if (!count) {complete=true;break;}
-    int dest=(rom[list+4]&127)*512-0xc000;
-    size_t source=lorom(word(list+1)|(rom[list+3]<<16));
-    if (!range(source,count) || dest<0 || dest+count>sizeof(art->tiles)) return NULL;
-    memcpy(art->tiles+dest,rom+source,count);
-    if (rom[list+4]&128) {complete=true;break;}
+  unsigned first=(!kind && pose==6) ? 4 : upload_pose;
+  for(unsigned pass=0;pass<(first!=upload_pose ? 2u : 1u);++pass) {
+    size_t list=table+word(table+(pass ? upload_pose : first)*2);
+    complete=false;
+    for (unsigned n=0;n<32;++n,list+=5) {
+      if (!range(list,5)) return NULL;
+      unsigned count=rom[list]*16;
+      if (!count) {complete=true;break;}
+      int dest=(rom[list+4]&127)*512-0xc000;
+      size_t source=lorom(word(list+1)|(rom[list+3]<<16));
+      if (!range(source,count) || dest<0 || dest+count>sizeof(art->tiles)) return NULL;
+      memcpy(art->tiles+dest,rom+source,count);
+      if (rom[list+4]&128) {complete=true;break;}
+    }
+    if (!complete) return NULL;
   }
-  if (!complete) return NULL;
   memcpy(art->colors,palette->colors,sizeof(art->colors));
   art->attributes=6;art->live_colors=true;charged_buster_ready[kind][pose]=true;
   return art;

src/mmx_renderer.c

@@ -1162,7 +1162,8 @@ static void coop_partner_row(const Ppu *ppu,const Raster *r,int y,MmxRenderView
        * Another seat can replace the shared $6200/$6300 weapon upload. */
       if(d>=0x1228 && ram[d+10]==0x0c && group==0x47 && (s.attr&0x0e00)==0x0600)
         asset=MmxRenderAssetsWeaponX(6,false);
-      if(d>=0x1228 && ((ram[d+10]==3 && group==0x9e) || (ram[d+10]==2 && group==0x0e))) {
+      if(d>=0x1228 && ((ram[d+10]==3 && group==0x9e) ||
+          ((ram[d+10]==1 || ram[d+10]==2) && group==0x0e))) {
         const MmxSpriteAsset *beam=MmxRenderAssetsChargedBuster(group,ram[d+23]&127);
         if(beam) asset=beam;
       }
@@ -1362,7 +1363,7 @@ bool MmxRendererDraw(uint32_t *out, MmxRenderView view, bool hud) {
       bool red_death = stage && s.animation == 0x1d && MmxZeroDeathOrbRed(frame.ram,s.object);
       bool coop_buster=stage && frame_coop.initialized && s.object>=0x1228 && s.object<0x1428 &&
           ((frame.ram[s.object+10]==3 && s.animation==0x9e) ||
-           (frame.ram[s.object+10]==2 && s.animation==0x0e));
+           ((frame.ram[s.object+10]==1 || frame.ram[s.object+10]==2) && s.animation==0x0e));
       bool menu_body = s.object == 0x1988 && (s.animation == 0 || s.animation == 0x18);
       bool zero_body = zero && (s.object == 0xba8 || menu_body);
       bool triad_x_body=cast_body && !zero && s.object==0xba8;

tests/mmx_coop_followup_test.inc

@@ -156,7 +156,7 @@ static unsigned coop_buster_pixels_equal(const uint32_t *a,const uint32_t *b,con
   const uint8_t *rom=g_snes->cart->rom;unsigned checked=0;
   for(unsigned seat=0;seat<2;++seat) for(unsigned slot=0;slot<8;++slot) {
     const uint8_t *q=state->players[seat].shots+slot*64;
-    if(!q[0] || (q[10]!=2 && q[10]!=3)) continue;
+    if(!q[0] || q[10]<1 || q[10]>3) continue;
     const MmxSpriteAsset *art=MmxRenderAssetsChargedBuster(q[22],q[23]&127);
     if(!art) continue;
     size_t directory=0x68000+q[22]*3;