Made adding to behaviors possible in Lua

docs/lua/examples/behavior-add-to-goomba.lua

@@ -0,0 +1,14 @@
+-- name: Goomba Leaps
+-- description: Makes goombas leap instead of just jump as an example.
+
+function bhv_custom_goomba_loop(obj)
+    -- make goombas leap instead of just jump
+    if obj.oGoombaJumpCooldown >= 9 then
+        obj.oGoombaJumpCooldown = 8
+        obj.oVelY = obj.oVelY + 20
+        obj.oForwardVel = 20
+    end
+end
+
+-- hook the behavior
+id_bhvCustomGoomba = hook_behavior(id_bhvGoomba, OBJ_LIST_PUSHABLE, false, nil, bhv_custom_goomba_loop)

docs/lua/examples/behavior-ball.lua

@@ -81,7 +81,7 @@ function bhv_ball_loop(obj)
     end
 end
 
-id_bhvBall = hook_behavior(0, OBJ_LIST_DEFAULT, bhv_ball_init, bhv_ball_loop)
+id_bhvBall = hook_behavior(nil, OBJ_LIST_DEFAULT, true, bhv_ball_init, bhv_ball_loop)
 
 function mario_update_local(m)
     if (m.controller.buttonPressed & D_JPAD) ~= 0 then

docs/lua/examples/behavior-replace-goomba.lua

@@ -92,4 +92,4 @@ function bhv_custom_goomba_loop(obj)
 end
 
 -- hook the behavior
-id_bhvCustomGoomba = hook_behavior(id_bhvGoomba, OBJ_LIST_PUSHABLE, bhv_custom_goomba_init, bhv_custom_goomba_loop)
+id_bhvCustomGoomba = hook_behavior(id_bhvGoomba, OBJ_LIST_PUSHABLE, true, bhv_custom_goomba_init, bhv_custom_goomba_loop)

docs/lua/functions.md

@@ -685,7 +685,9 @@
 
 ## [define_custom_obj_fields](#define_custom_obj_fields)
 
-Defines a custom set of overlapping object fields. The `fieldTable` table's keys must start with the letter `o` and the values must be either `u32`, `s32`, or `f32`.
+Defines a custom set of overlapping object fields.
+
+The `fieldTable` table's keys must start with the letter `o` and the values must be either `u32`, `s32`, or `f32`.
 
 ### Lua Example
 `define_custom_obj_fields({ oCustomField1 = 'u32', oCustomField2 = 's32', oCustomField3 = 'f32' })`

docs/lua/hooks.md

@@ -19,8 +19,9 @@ Hooks are a way for SM64 to trigger Lua code, whereas the functions listed in [f
 
 | Field | Type | Notes |
 | ----- | ---- | ----- |
-| behaviorId | [enum BehaviorId](constants.md#enum-BehaviorId) | Set to `0` to create a new behavior |
+| behaviorId | [enum BehaviorId](constants.md#enum-BehaviorId) | Set to `nil` to create a new behavior |
 | objectList | [enum ObjectList](constants.md#enum-ObjectList) |  |
+| replaceBehavior | `bool` | Prevents the original behavior code from running |
 | initFunction | `Lua Function` ([Object](structs.md#Object) obj) | Runs once per object |
 | loopFunction | `Lua Function` ([Object](structs.md#Object) obj) | Runs once per frame per object |
 

docs/lua/lua.md

@@ -49,4 +49,5 @@ All of this is a holdover from when there were only two players. It was a reason
 - [HUD Rendering](examples/hud.lua)
 - [Object Spawning](examples/spawn-stuff.lua)
 - [Custom Ball Behavior](examples/behavior-ball.lua)
-- [Replace Goomba Behavior](examples/behavior-goomba.lua)
+- [Replace Goomba Behavior](examples/behavior-replace-goomba.lua)
+- [Add to Goomba Behavior](examples/behavior-add-to-goomba.lua)

src/engine/behavior_script.c

@@ -1023,7 +1023,7 @@ cur_obj_update_begin:;
 
     // Execute the behavior script.
     gCurBhvCommand = gCurrentObject->curBhvCommand;
-    u8 skipBehavior = smlua_call_behavior_hook(&gCurBhvCommand, gCurrentObject);
+    u8 skipBehavior = smlua_call_behavior_hook(&gCurBhvCommand, gCurrentObject, true);
 
     if (!skipBehavior) {
         do {
@@ -1031,6 +1031,8 @@ cur_obj_update_begin:;
             bhvProcResult = bhvCmdProc();
         } while (bhvProcResult == BHV_PROC_CONTINUE);
     }
+
+    smlua_call_behavior_hook(&gCurBhvCommand, gCurrentObject, false);
     gCurrentObject->curBhvCommand = gCurBhvCommand;
 
     // Increment the object's timer.

src/game/spawn_object.c

@@ -335,13 +335,12 @@ struct Object *create_object(const BehaviorScript *bhvScript) {
     s32 objListIndex;
     struct Object *obj;
     struct ObjectNode *objList;
-    bhvScript = smlua_override_behavior(bhvScript);
-    const BehaviorScript *behavior = bhvScript;
+    const BehaviorScript *behavior = smlua_override_behavior(bhvScript);
 
     // If the first behavior script command is "begin <object list>", then
     // extract the object list from it
-    if ((bhvScript[0] >> 24) == 0) {
-        objListIndex = (bhvScript[0] >> 16) & 0xFFFF;
+    if ((behavior[0] >> 24) == 0) {
+        objListIndex = (behavior[0] >> 16) & 0xFFFF;
     } else {
         objListIndex = OBJ_LIST_DEFAULT;
     }

src/pc/lua/smlua_hooks.c

@@ -307,8 +307,10 @@ struct LuaHookedBehavior {
     u32 behaviorId;
     u32 overrideId;
     BehaviorScript behavior[2];
+    const BehaviorScript* originalBehavior;
     int initReference;
     int loopReference;
+    bool replace;
     struct ModListEntry* entry;
 };
 
@@ -340,7 +342,7 @@ const BehaviorScript* get_lua_behavior_from_id(enum BehaviorId id) {
 
 int smlua_hook_behavior(lua_State* L) {
     if (L == NULL) { return 0; }
-    if (!smlua_functions_valid_param_count(L, 4)) { return 0; }
+    if (!smlua_functions_valid_param_count(L, 5)) { return 0; }
 
     if (gLuaLoadingEntry == NULL) {
         LOG_LUA("hook_behavior() can only be called on load.");
@@ -353,7 +355,9 @@ int smlua_hook_behavior(lua_State* L) {
         return 0;
     }
 
-    lua_Integer overrideBehaviorId = smlua_to_integer(L, 1);
+    bool noOverrideId = (lua_type(L, 1) == LUA_TNIL);
+    gSmLuaConvertSuccess = true;
+    lua_Integer overrideBehaviorId = noOverrideId ? 0xFFFFFF : smlua_to_integer(L, 1);
     if (!gSmLuaConvertSuccess) {
         LOG_LUA("Hook behavior: tried to override invalid behavior: %lld, %u", overrideBehaviorId, gSmLuaConvertSuccess);
         smlua_logline();
@@ -367,13 +371,24 @@ int smlua_hook_behavior(lua_State* L) {
         return 0;
     }
 
+    bool replaceBehavior = smlua_to_boolean(L, 3);
+    if (!gSmLuaConvertSuccess) {
+        LOG_LUA("Hook behavior: could not parse replaceBehavior");
+        smlua_logline();
+        return 0;
+    }
+    const BehaviorScript* originalBehavior = noOverrideId ? NULL : get_behavior_from_id(overrideBehaviorId);
+    if (originalBehavior == NULL) {
+        replaceBehavior = true;
+    }
+
     int initReference = 0;
-    int initReferenceType = lua_type(L, 3);
+    int initReferenceType = lua_type(L, 4);
     if (initReferenceType == LUA_TNIL) {
         // nothing
     } else if (initReferenceType == LUA_TFUNCTION) {
         // get reference
-        lua_pushvalue(L, 3);
+        lua_pushvalue(L, 4);
         initReference = luaL_ref(L, LUA_REGISTRYINDEX);
     } else {
         LOG_LUA("Hook behavior: tried to reference non-function for init");
@@ -382,12 +397,12 @@ int smlua_hook_behavior(lua_State* L) {
     }
 
     int loopReference = 0;
-    int loopReferenceType = lua_type(L, 4);
+    int loopReferenceType = lua_type(L, 5);
     if (loopReferenceType == LUA_TNIL) {
         // nothing
     } else if (loopReferenceType == LUA_TFUNCTION) {
         // get reference
-        lua_pushvalue(L, 4);
+        lua_pushvalue(L, 5);
         loopReference = luaL_ref(L, LUA_REGISTRYINDEX);
     } else {
         LOG_LUA("Hook behavior: tried to reference non-function for loop");
@@ -398,11 +413,13 @@ int smlua_hook_behavior(lua_State* L) {
     struct LuaHookedBehavior* hooked = &sHookedBehaviors[sHookedBehaviorsCount];
     u16 customBehaviorId = (sHookedBehaviorsCount & 0xFFFF) | LUA_BEHAVIOR_FLAG;
     hooked->behaviorId = customBehaviorId;
-    hooked->overrideId = (overrideBehaviorId == 0) ? customBehaviorId : overrideBehaviorId;
+    hooked->overrideId = noOverrideId ? customBehaviorId : overrideBehaviorId;
     hooked->behavior[0] = (((unsigned int) (((unsigned int)(0x00) & ((0x01 << (8)) - 1)) << (24))) | ((unsigned int) (((unsigned int)(objectList) & ((0x01 << (8)) - 1)) << (16)))); // gross. this is BEGIN(objectList)
     hooked->behavior[1] = (((unsigned int) (((unsigned int)(0x39) & ((0x01 << (8)) - 1)) << (24))) | ((unsigned int) (((unsigned int)(customBehaviorId) & ((0x01 << (16)) - 1)) << (0)))); // gross. this is ID(customBehaviorId)
+    hooked->originalBehavior = originalBehavior ? originalBehavior : hooked->behavior;
     hooked->initReference = initReference;
     hooked->loopReference = loopReference;
+    hooked->replace = replaceBehavior;
     hooked->entry = gLuaActiveEntry;
 
     sHookedBehaviorsCount++;
@@ -413,7 +430,7 @@ int smlua_hook_behavior(lua_State* L) {
     return 1;
 }
 
-bool smlua_call_behavior_hook(const BehaviorScript** behavior, struct Object* object) {
+bool smlua_call_behavior_hook(const BehaviorScript** behavior, struct Object* object, bool before) {
     lua_State* L = gLuaState;
     if (L == NULL) { return false; }
     for (int i = 0; i < sHookedBehaviorsCount; i++) {
@@ -424,9 +441,17 @@ bool smlua_call_behavior_hook(const BehaviorScript** behavior, struct Object* ob
             continue;
         }
 
+        // figure out whether to run before or after
+        if (before && !hooked->replace) {
+            return false;
+        }
+        if (!before && hooked->replace) {
+            return false;
+        }
+
         // retrieve and remember first run
-        bool firstRun = (*behavior == hooked->behavior);
-        if (firstRun) { *behavior = &hooked->behavior[1]; }
+        bool firstRun = (object->curBhvCommand == hooked->originalBehavior);
+        if (firstRun && hooked->replace) { *behavior = &hooked->behavior[1]; }
 
         // get function and null check it
         int reference = firstRun ? hooked->initReference : hooked->loopReference;
@@ -447,12 +472,13 @@ bool smlua_call_behavior_hook(const BehaviorScript** behavior, struct Object* ob
             return true;
         }
 
-        return true;
+        return hooked->replace;
     }
 
     return false;
 }
 
+
   /////////////////////////
  // hooked chat command //
 /////////////////////////
@@ -672,8 +698,10 @@ static void smlua_clear_hooks(void) {
         hooked->behaviorId = 0;
         hooked->behavior[0] = 0;
         hooked->behavior[1] = 0;
+        hooked->originalBehavior = NULL;
         hooked->initReference = 0;
         hooked->loopReference = 0;
+        hooked->replace = false;
         hooked->entry = NULL;
     }
     sHookedBehaviorsCount = 0;

src/pc/lua/smlua_hooks.h

@@ -39,7 +39,7 @@ void smlua_call_event_hooks_interact_params(enum LuaHookedEventType hookType, st
 
 const BehaviorScript* smlua_override_behavior(const BehaviorScript* behavior);
 const BehaviorScript* get_lua_behavior_from_id(enum BehaviorId id);
-bool smlua_call_behavior_hook(const BehaviorScript** behavior, struct Object* object);
+bool smlua_call_behavior_hook(const BehaviorScript** behavior, struct Object* object, bool before);
 
 bool smlua_call_action_hook(struct MarioState* m, s32* returnValue);
 u32 smlua_get_action_interaction_type(struct MarioState* m);