Expose missing TearParams attributes

Author: ConnorForan

changelog.txt

@@ -85,6 +85,11 @@ Added:
 * EntityKnife
 	- SetKnifeDistance
 	- SetKnifeVelocity
+* TearParams
+	- MassMultiplier
+	- KnockbackMultiplier
+	- SpeedMultiplier
+	- TearDisplacement
 * PersistentGameData:
 	- Unlock: same as TryUnlock but it overrides situations where TryUnlock would be blocked normally (Challenges)
 * RoomDescriptor

libzhl/functions/TearParams.zhl

@@ -8,9 +8,16 @@ struct TearParams depends (BitSet128, ColorMod) {
 		this->constructor();
 	}
 }} 
-	unsigned int _tearVariant : 0x0, _bombVariant : 0x4;
+	int _tearVariant : 0x0;
+	int _bombVariant : 0x4;  // Does the game even use this?
 	ColorMod _tearColor : 0x8;
+	int _unused : 0x34;  // Not set by constructor
 	BitSet128 _flags : 0x38;
-	float _tearDamage : 0x48, _tearScale : 0x4c, _tearHeight : 0x50;
-	
-} : 0x68;
+	float _tearDamage : 0x48;
+	float _tearScale : 0x4c;
+	float _tearHeight : 0x50;
+	float _massMultiplier : 0x54;
+	float _knockbackMultiplier : 0x58;
+	float _speedMultiplier : 0x5c;  // Vanilla only uses this for Stye, but it works fine
+	int _tearDisplacement : 0x60;
+} : 0x64;

repentogon/LuaInterfaces/LuaTearParams.cpp

@@ -0,0 +1,77 @@
+#include "IsaacRepentance.h"
+#include "LuaCore.h"
+#include "HookSystem.h"
+
+LUA_FUNCTION(Lua_TearParams_GetMassMultiplier) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	lua_pushnumber(L, params->_massMultiplier);
+	return 1;
+}
+LUA_FUNCTION(Lua_TearParams_SetMassMultiplier) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	float value = (float)luaL_checknumber(L, 2);
+	if (value <= 0) {
+		return luaL_argerror(L, 2, "MassMultiplier must be positive!");
+	}
+	params->_massMultiplier = value;
+	return 0;
+}
+
+LUA_FUNCTION(Lua_TearParams_GetKnockbackMultiplier) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	lua_pushnumber(L, params->_knockbackMultiplier);
+	return 1;
+}
+LUA_FUNCTION(Lua_TearParams_SetKnockbackMultiplier) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	float value = (float)luaL_checknumber(L, 2);
+	if (value <= 0) {
+		return luaL_argerror(L, 2, "KnockbackMultiplier must be positive!");
+	}
+	params->_knockbackMultiplier = value;
+	return 0;
+}
+
+LUA_FUNCTION(Lua_TearParams_GetSpeedMultiplier) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	lua_pushnumber(L, params->_speedMultiplier);
+	return 1;
+}
+LUA_FUNCTION(Lua_TearParams_SetSpeedMultiplier) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	params->_speedMultiplier = (float)luaL_checknumber(L, 2);
+	return 0;
+}
+
+LUA_FUNCTION(Lua_TearParams_GetTearDisplacement) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	lua_pushinteger(L, params->_tearDisplacement);
+	return 1;
+}
+LUA_FUNCTION(Lua_TearParams_SetTearDisplacement) {
+	TearParams* params = lua::GetLuabridgeUserdata<TearParams*>(L, 1, lua::Metatables::TEAR_PARAMS, "TearParams");
+	int value = (int)luaL_checkinteger(L, 2);
+	if (value < -1 || value > 1) {
+		// 0 is technically "valid" in that the game can sometimes allow it via GetTearHitParams.
+		// I dunno what the implication of having it be zero is though, it doesn't seem entirely intentional.
+		// Not treating 0 as an error, but also not going to mention it in the error message.
+		return luaL_argerror(L, 2, "TearDisplacement may only be set to -1 or 1");
+	}
+	params->_tearDisplacement = value;
+	return 0;
+}
+
+inline void RegisterTearParamsVariable(lua_State* L, const char* name, lua_CFunction getFunc, lua_CFunction setFunc) {
+	lua::RegisterVariable(L, lua::Metatables::TEAR_PARAMS, name, getFunc, setFunc);
+	lua::RegisterVariableGetter(L, lua::Metatables::CONST_TEAR_PARAMS, name, getFunc);
+}
+HOOK_METHOD(LuaEngine, RegisterClasses, () -> void) {
+	super();
+
+	lua::LuaStackProtector protector(_state);
+
+	RegisterTearParamsVariable(_state, "MassMultiplier", Lua_TearParams_GetMassMultiplier, Lua_TearParams_SetMassMultiplier);
+	RegisterTearParamsVariable(_state, "KnockbackMultiplier", Lua_TearParams_GetKnockbackMultiplier, Lua_TearParams_SetKnockbackMultiplier);
+	RegisterTearParamsVariable(_state, "SpeedMultiplier", Lua_TearParams_GetSpeedMultiplier, Lua_TearParams_SetSpeedMultiplier);
+	RegisterTearParamsVariable(_state, "TearDisplacement", Lua_TearParams_GetTearDisplacement, Lua_TearParams_SetTearDisplacement);
+}