l_particleparams.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2021 velartrill, Lexi Hale <lexi@hale.su>
 
#pragma once
#include "lua_api/l_object.h"
#include "common/c_converter.h"
#include "common/c_content.h"
#include "server/serveractiveobject.h"
#include "particles.h"
 
namespace LuaParticleParams
{
        using namespace ParticleParamTypes;
 
        template<typename T>
        inline void readNumericLuaValue(lua_State* L, T& ret)
        {
                if (lua_isnil(L,-1))
                        return;
 
                if (std::is_integral<T>())
                        ret = lua_tointeger(L, -1);
                else
                        ret = lua_tonumber(L, -1);
        }
 
        template <typename T, size_t N>
        inline void readNumericLuaValue(lua_State* L, Parameter<T,N>& ret)
        {
                readNumericLuaValue<T>(L, ret.val);
        }
 
        // these are unfortunately necessary as C++ intentionally disallows function template
        // specialization and there's no way to make template overloads reliably resolve correctly
        inline void readLuaValue(lua_State* L, f32Parameter& ret) { readNumericLuaValue(L, ret); }
        inline void readLuaValue(lua_State* L, f32& ret)          { readNumericLuaValue(L, ret); }
        inline void readLuaValue(lua_State* L, u16& ret)          { readNumericLuaValue(L, ret); }
        inline void readLuaValue(lua_State* L, u8& ret)           { readNumericLuaValue(L, ret); }
 
        inline void readLuaValue(lua_State* L, v3fParameter& ret)
        {
                if (lua_isnil(L, -1))
                        return;
 
                if (lua_isnumber(L, -1)) { // shortcut for uniform vectors
                        auto n = lua_tonumber(L, -1);
                        ret = v3fParameter(n,n,n);
                } else {
                        ret = (v3fParameter)check_v3f(L, -1);
                }
        }
 
        inline void readLuaValue(lua_State* L, v2fParameter& ret)
        {
                if (lua_isnil(L, -1))
                        return;
 
                if (lua_isnumber(L, -1)) { // shortcut for uniform vectors
                        auto n = lua_tonumber(L, -1);
                        ret = v2fParameter(n,n);
                } else {
                        ret = (v2fParameter)check_v2f(L, -1);
                }
        }
 
        inline void readLuaValue(lua_State* L, TweenStyle& ret)
        {
                if (lua_isnil(L, -1))
                        return;
 
                static const EnumString opts[] = {
                        {(int)TweenStyle::fwd,     "fwd"},
                        {(int)TweenStyle::rev,     "rev"},
                        {(int)TweenStyle::pulse,   "pulse"},
                        {(int)TweenStyle::flicker, "flicker"},
                        {0, nullptr},
                };
 
                luaL_checktype(L, -1, LUA_TSTRING);
                int v = (int)TweenStyle::fwd;
                if (!string_to_enum(opts, v, lua_tostring(L, -1))) {
                        throw LuaError("tween style must be one of ('fwd', 'rev', 'pulse', 'flicker')");
                }
                ret = (TweenStyle)v;
        }
 
        inline void readLuaValue(lua_State* L, AttractorKind& ret)
        {
                if (lua_isnil(L, -1))
                        return;
 
                static const EnumString opts[] = {
                        {(int)AttractorKind::none,  "none"},
                        {(int)AttractorKind::point, "point"},
                        {(int)AttractorKind::line,  "line"},
                        {(int)AttractorKind::plane, "plane"},
                        {0, nullptr},
                };
 
                luaL_checktype(L, -1, LUA_TSTRING);
                int v = (int)AttractorKind::none;
                if (!string_to_enum(opts, v, lua_tostring(L, -1))) {
                        throw LuaError("attractor kind must be one of ('none', 'point', 'line', 'plane')");
                }
                ret = (AttractorKind)v;
        }
 
        inline void readLuaValue(lua_State* L, BlendMode& ret)
        {
                if (lua_isnil(L, -1))
                        return;
 
                static const EnumString opts[] = {
                        {(int)BlendMode::alpha,  "alpha"},
                        {(int)BlendMode::add,    "add"},
                        {(int)BlendMode::sub,    "sub"},
                        {(int)BlendMode::screen, "screen"},
                        {(int)BlendMode::clip,   "clip"},
                        {0, nullptr},
                };
 
                luaL_checktype(L, -1, LUA_TSTRING);
                int v = (int)BlendMode::alpha;
                if (!string_to_enum(opts, v, lua_tostring(L, -1))) {
                        throw LuaError("blend mode must be one of ('alpha', 'clip', 'add', 'sub', 'screen')");
                }
                ret = (BlendMode)v;
        }
 
        template <typename T> void
        readLuaValue(lua_State* L, RangedParameter<T>& field)
        {
                if (lua_isnil(L,-1))
                        return;
                if (!lua_istable(L,-1)) // is this is just a literal value?
                        goto set_uniform;
 
                lua_getfield(L, -1, "min");
                // handle convenience syntax for non-range values
                if (lua_isnil(L,-1)) {
                        lua_pop(L, 1);
                        goto set_uniform;
                }
                readLuaValue(L,field.min);
                lua_pop(L, 1);
 
                lua_getfield(L, -1, "max");
                readLuaValue(L,field.max);
                lua_pop(L, 1);
 
                lua_getfield(L, -1, "bias");
                if (!lua_isnil(L,-1))
                        readLuaValue(L,field.bias);
                lua_pop(L, 1);
                return;
 
                set_uniform:
                readLuaValue(L, field.min);
                readLuaValue(L, field.max);
        }
 
        template <typename T> void
        readLegacyValue(lua_State* L, const char* name, T& field) {}
 
        template <typename T> void
        readLegacyValue(lua_State* L, const char* name, RangedParameter<T>& field)
        {
                int tbl = lua_gettop(L);
                lua_pushliteral(L, "min");
                lua_pushstring(L, name);
                lua_concat(L, 2);
                lua_gettable(L, tbl);
                if (!lua_isnil(L, -1)) {
                        readLuaValue(L, field.min);
                }
                lua_settop(L, tbl);
 
                lua_pushliteral(L, "max");
                lua_pushstring(L, name);
                lua_concat(L, 2);
                lua_gettable(L, tbl);
                if (!lua_isnil(L, -1)) {
                        readLuaValue(L, field.max);
                }
                lua_settop(L, tbl);
        }
 
        template <typename T> void
        readTweenTable(lua_State* L, const char* name, TweenedParameter<T>& field)
        {
                int tbl = lua_gettop(L);
 
                lua_pushstring(L, name);
                lua_pushliteral(L, "_tween");
                lua_concat(L, 2);
                lua_gettable(L, tbl);
                if(lua_istable(L, -1)) {
                        int tween = lua_gettop(L);
                        // get the starting value
                        lua_pushinteger(L, 1), lua_gettable(L, tween);
                        readLuaValue(L, field.start);
                        lua_pop(L, 1);
 
                        // get the final value -- use len instead of 2 so that this
                        // gracefully degrades if keyframe support is later added
                        lua_pushinteger(L, (lua_Integer)lua_objlen(L, -1)), lua_gettable(L, tween);
                        readLuaValue(L, field.end);
                        lua_pop(L, 1);
 
                        // get the effect settings
                        lua_getfield(L, -1, "style");
                        if (!lua_isnil(L,-1))
                                readLuaValue(L, field.style);
                        lua_pop(L, 1);
 
                        lua_getfield(L, -1, "reps");
                        if (!lua_isnil(L,-1))
                                readLuaValue(L, field.reps);
                        lua_pop(L, 1);
 
                        lua_getfield(L, -1, "start");
                        if (!lua_isnil(L,-1))
                                readLuaValue(L, field.beginning);
                        lua_pop(L, 1);
 
                        goto done;
                } else {
                        lua_pop(L,1);
                }
                // the table is not present; check for nonanimated values
 
                lua_getfield(L, tbl, name);
                if(!lua_isnil(L, -1)) {
                        readLuaValue(L, field.start);
                        lua_settop(L, tbl);
                        goto set_uniform;
                } else {
                        lua_pop(L,1);
                }
 
                // the goto did not trigger, so this table is not present either
                // check for pre-5.6.0 legacy values
                readLegacyValue(L, name, field.start);
 
                set_uniform:
                field.end = field.start;
                done:
                lua_settop(L, tbl); // clean up after ourselves
        }
 
        inline u16 readAttachmentID(lua_State* L, const char* name)
        {
                u16 id = 0;
                lua_getfield(L, -1, name);
                if (!lua_isnil(L, -1)) {
                        ObjectRef *ref = ModApiBase::checkObject<ObjectRef>(L, -1);
                        if (auto obj = ObjectRef::getobject(ref))
                                id = obj->getId();
                }
                lua_pop(L, 1);
                return id;
        }
 
        void readTexValue(lua_State* L, ServerParticleTexture& tex);
}