I think someone eats this

dirt.lua

--[[
Dirt v4
It's... dirt. And a few related elements.

v4:
- Added FIRT
- DIRT falling into water now separates into CLST & SLCN

v3:
- Heat dries DIRT
- DIRT melting temperature corrected

v2:
- Increased DIRT moisture spread
- Fixed ADOB colours when generated from MUD
- Increased MUD -> ADOB transition temperature
]]


local elem, sim = elements, sim
local elemDef, elemProp = elem.element, elem.property
local partProp, partKill, exists, partCreate = sim.partProperty, sim.partKill, sim.partExists, sim.partCreate

local random, abs, sqrt = math.random, math.abs, math.sqrt

local DIRT, MUD, GRAS, ADOB, FIRT = elem.allocate("dirt", "dirt"), elem.allocate("dirt", "mud"), elem.allocate("dirt", "gras"), elem.allocate("dirt", "adob"), elem.allocate("dirt", "firt")

local function set(tbl, ...) for _, el in ipairs({...}) do tbl[el] = true end end
local waterLike = {}
set(waterLike, elem.DEFAULT_PT_WATR, elem.DEFAULT_PT_SLTW, elem.DEFAULT_PT_DSTW, elem.DEFAULT_PT_BUBW)


elemDef(DIRT, elemDef(elem.DEFAULT_PT_CLST))

elemProp(DIRT, "Name", "DIRT")
elemProp(DIRT, "Description", "Dirt. Absorbs water like a sponge, supports GRAS spread.")

elemProp(DIRT, "Color", 0x885A33)
elemProp(DIRT, "Hardness", 20)
elemProp(DIRT, "Weight", 60)
elemProp(DIRT, "Properties", elemProp(DIRT, "Properties") + elem.PROP_HOT_GLOW)

elemProp(DIRT, "HighTemperature", 3273.15)

elemProp(DIRT, "Create", function (self, x, y, type, v)
    partProp(self, sim.FIELD_TMP2, random(0, 64))
end)
elemProp(DIRT, "Update", function (self, x, y, s, nt)
    local temp = partProp(self, sim.FIELD_TEMP)
    if temp >= 373.15 and partProp(self, sim.FIELD_LIFE) > 0 then
        partProp(self, sim.FIELD_LIFE, partProp(self, sim.FIELD_LIFE) - 1)
    elseif temp <= 273.15 and random(1, 100) == 1 then
        partProp(self, sim.FIELD_TYPE, FIRT)
    end
    
    local vx, vy = partProp(self, sim.FIELD_VX), partProp(self, sim.FIELD_VY)
    local v2 = vx * vx + vy * vy
    
    if v2 > 1 then
        for dx = -1, 1 do
            for dy = -1, 1 do
                local part = sim.pmap(x + dx, y + dy)
                if part and part ~= self and exists(part) then
                    local type = partProp(part, sim.FIELD_TYPE)
                    
                    if waterLike[type] then
                        partKill(self)
                        partCreate(-3, x, y, random(0, 1) == 0 and elem.DEFAULT_PT_CLST or elem.DEFAULT_PT_SLCN)
                        return
                    end
                end
            end
        end
    end
    
    if random(1, 20) ~= 1 then return end
    
    local initialLife = partProp(self, sim.FIELD_LIFE)
    for dx = -2, 2 do
        for dy = -2, 2 do
            local part = sim.pmap(x + dx, y + dy)
            if part and part ~= self and exists(part) then
                local type = partProp(part, sim.FIELD_TYPE)
                
                if type == DIRT then
                    if abs(dx) < 2 and abs(dy) < 2 then
                        local dx, dy = partProp(part, sim.FIELD_X) - x, partProp(part, sim.FIELD_Y) - y
                        local nd = dx ^ 2 + dy ^ 2 - 0.5
                        
                        dx, dy = dx * 0.1, dy * 0.1
                        
                        partProp(self, sim.FIELD_VX, partProp(self, sim.FIELD_VX) + dx)
                        partProp(self, sim.FIELD_VY, partProp(self, sim.FIELD_VY) + dy)
                        
                        partProp(part, sim.FIELD_VX, partProp(part, sim.FIELD_VX) - dx)
                        partProp(part, sim.FIELD_VY, partProp(part, sim.FIELD_VY) - dy)
                    end
                    
                    if initialLife > 0 and random(1, 4) == 1 then
                        local life, partLife = partProp(self, sim.FIELD_LIFE), partProp(part, sim.FIELD_LIFE)
                        if life - partLife > random(1, 16) then
                            partProp(self, sim.FIELD_LIFE, life - 1)
                            partProp(part, sim.FIELD_LIFE, partLife + 1)
                        end
                    end
                elseif waterLike[type] then
                    if random(1, 30) == 1 then
                        local life = partProp(self, sim.FIELD_LIFE)
                        
                        partProp(self, sim.FIELD_LIFE, life + 4)
                        partKill(part)
                    end
                elseif type == GRAS then
                    local life = partProp(self, sim.FIELD_LIFE)
                    
                    if life > 0 then
                        local growDX, growDY = random(-1, 1), random(-1, 1)
                        local growPart = sim.pmap(x + growDX, y + growDY)
                        
                        partProp(self, sim.FIELD_LIFE, life - 1)
                        if not growPart or not exists(growPart) then
                            partCreate(-1, x + growDX, y + growDY, GRAS)
                        elseif random(1, 20) == 1 then
                            partProp(part, sim.FIELD_LIFE, partProp(part, sim.FIELD_LIFE) + 1)
                        end
                    end
                end
            end
        end
    end
    
    if partProp(self, sim.FIELD_LIFE) > 64 then
        partProp(self, sim.FIELD_TYPE, MUD)
    end
end)
elemProp(DIRT, "Graphics", function (self, r, g, b)
    local shade, moisture = partProp(self, sim.FIELD_TMP2), partProp(self, sim.FIELD_LIFE)
    local brightness = 1 - (moisture / 128)
    
    r, g, b = r + shade, g + shade, b + shade
    r, g, b = r * brightness, g * brightness, b * brightness
    
    return 0, ren.PMODE_FLAT, 255, r, g, b, 255, r, g, b
end)


elemDef(GRAS, elemDef(elem.DEFAULT_PT_PLNT))

elemProp(GRAS, "Name", "GRAS")
elemProp(GRAS, "Description", "Grass. Thrives on moist dirt.")

elemProp(GRAS, "Color", 0x009900)
elemProp(GRAS, "Properties", elem.TYPE_SOLID + elem.PROP_NEUTPENETRATE)

elemProp(GRAS, "Create", function (self, x, y, type, v)
    partProp(self, sim.FIELD_TMP2, random(0, 64))
end)
elemProp(GRAS, "Update", function (self, x, y, s, nt)
    local part = sim.pmap(x, y - 1)
    local life = partProp(self, sim.FIELD_LIFE)
    
    if part and part ~= self and exists(part) then
        local type = partProp(part, sim.FIELD_TYPE)
        if waterLike[type] then
            partKill(part)
            life = life + (random(1, 20) == 1 and 1 or 0)
            partProp(self, sim.FIELD_LIFE, life)
        elseif type == GRAS then
            partProp(self, sim.FIELD_LIFE, 0)
            partProp(part, sim.FIELD_LIFE, life)
            return
        else
            return
        end
    end
    
    if life > 0 then
        partProp(self, sim.FIELD_LIFE, 0)
        
        local newGrass = partCreate(-1, x, y - 1, GRAS)
        partProp(newGrass, sim.FIELD_LIFE, life - 1)
        partProp(newGrass, sim.FIELD_TMP2, partProp(self, sim.FIELD_TMP2))
    end
end)
elemProp(GRAS, "Graphics", function (self, r, g, b)
    local shade = partProp(self, sim.FIELD_TMP2)
    
    r, g, b = r + shade, g + shade, b + shade
    
    return 0, ren.PMODE_FLAT, 255, r, g, b, 255, r, g, b
end)


elemDef(MUD, elemDef(elem.DEFAULT_PT_WATR))

elemProp(MUD, "Name", "MUD")
elemProp(MUD, "Description", "Mud. Mixture of water and dirt. Dries into adobe.")

elemProp(MUD, "Color", 0x773A00)
elemProp(MUD, "Hardness", 20)
elemProp(MUD, "Weight", 60)

elemProp(MUD, "HighTemperature", math.huge)

elemProp(MUD, "Update", function (self, x, y, s, nt)
    if partProp(self, sim.FIELD_TEMP) > 473.15 then
        partProp(self, sim.FIELD_TYPE, ADOB)
        partProp(self, sim.FIELD_TMP2, random(0, 64))
    end
    
    if random(1, 5) ~= 1 then return end
    
    for dx = -1, 1 do
        for dy = -1, 1 do
            local part = sim.pmap(x + dx, y + dy)
            if part and part ~= self and exists(part) then
                local type = partProp(part, sim.FIELD_TYPE)
                
                if type == MUD then
                    local dx, dy = partProp(part, sim.FIELD_X) - x, partProp(part, sim.FIELD_Y) - y
                    local nd = dx ^ 2 + dy ^ 2 - 0.5
                    
                    dx, dy = dx * 0.1, dy * 0.1
                    
                    partProp(self, sim.FIELD_VX, partProp(self, sim.FIELD_VX) + dx)
                    partProp(self, sim.FIELD_VY, partProp(self, sim.FIELD_VY) + dy)
                    
                    partProp(part, sim.FIELD_VX, partProp(part, sim.FIELD_VX) - dx)
                    partProp(part, sim.FIELD_VY, partProp(part, sim.FIELD_VY) - dy)
                end
            end
        end
    end
end)


elemDef(ADOB, elemDef(elem.DEFAULT_PT_ROCK))

elemProp(ADOB, "Name", "ADOB")
elemProp(ADOB, "Description", "Adobe. Dried mud, useful building material.")

elemProp(ADOB, "Color", 0xAA8855)
elemProp(ADOB, "Hardness", 20)

elemProp(ADOB, "Create", function (self, x, y, type, v)
    partProp(self, sim.FIELD_TMP2, random(0, 64))
end)
elemProp(ADOB, "Update", function (self, x, y, s, nt)
    if random(1, 5) ~= 1 then return end
    
    for dx = -2, 2 do
        for dy = -2, 2 do
            local part = sim.pmap(x + dx, y + dy)
            if part and part ~= self and exists(part) then
                local type = partProp(part, sim.FIELD_TYPE)
                
                if waterLike[type] then
                    partProp(self, sim.FIELD_TYPE, MUD)
                    partKill(part)
                    return
                end
            end
        end
    end
end)
elemProp(ADOB, "Graphics", function (self, r, g, b)
    local shade = partProp(self, sim.FIELD_TMP2)
    
    r, g, b = r + shade, g + shade, b + shade
    
    return 0, ren.PMODE_FLAT, 255, r, g, b, 255, r, g, b
end)


elemDef(FIRT, elemDef(DIRT))

elemProp(FIRT, "Name", "FIRT")
elemProp(FIRT, "Description", "Firt. The result of exposing dirt to freezing temperatures.")

elemProp(FIRT, "Color", 0x88AAFF)

elemProp(FIRT, "Temperature", 258.15)
elemProp(FIRT, "HighTemperature", math.huge)
elemProp(FIRT, "HighTemperatureTransition", DIRT)

elemProp(FIRT, "Create", function (self, x, y, type, v)
    partProp(self, sim.FIELD_TMP2, random(0, 64))
end)
elemProp(FIRT, "Update", function (self, x, y, s, nt)
    if partProp(self, sim.FIELD_TEMP) >= 273.15 and random(1, 100) == 1 then
        partProp(self, sim.FIELD_LIFE, 48)
        partProp(self, sim.FIELD_TYPE, DIRT)
    end
end)
elemProp(FIRT, "Graphics", function (self, r, g, b)
    local shade = partProp(self, sim.FIELD_TMP2)
    r, g, b = r + shade, g + shade, b + shade
    
    return 0, ren.PMODE_FLAT, 255, r, g, b, 255, r, g, b
end)