Reworked Physics

init.lua

@@ -37,28 +37,40 @@ else
 end
 
 core.register_on_placenode(function(pos, newnode, placer, oldnode, itemstack, pointed_thing)
-    if internal.get_liquid_id(core.get_node(pos).name) ~= nil then
-        internal.add_node_to_check(pos)
-    end
+    --core.chat_send_all("Placed AT: " .. dump(pos) .. "___")
+    -- if internal.get_liquid_id(core.get_node(pos).name) ~= nil then
+    --     internal.add_node_to_check(pos)
+    -- end
 end)
 
-core.register_lbm {
-    name = "liquid_physics:update",
-    nodenames = "group:liquid_physics",
-    run_at_every_load = true,
-    action = function(pos, node, dtime_s)
-        internal.add_node_to_check(pos)
-    end,
-}
+-- core.register_lbm {
+--     name = "liquid_physics:update",
+--     nodenames = "group:liquid_physics",
+--     run_at_every_load = true,
+--     action = function(pos, node, dtime_s)
+--         --internal.add_node_to_check(pos)
+--         core.set_node(pos, { name = "air" })
+--     end,
+-- }
 
-core.register_abm({
-    nodenames = "group:liquid_physics",
-    neighbors = { "air" },
-    interval  = 0.2,
-    chance    = 0,
-    action    = function(pos, node, active_object_count, active_object_count_wider)
-        internal.add_node_to_check(pos)
-    end
-})
+-- core.register_lbm {
+--     name = "liquid_physics:update",
+--     nodenames = "group:liquid_physics",
+--     run_at_every_load = true,
+--     action = function(pos, node, dtime_s)
+--         --internal.add_node_to_check(pos)
+--         core.set_node(pos, { name = "air" })
+--     end,
+-- }
+
+-- core.register_abm({
+--     nodenames = "group:liquid_physics",
+--     neighbors = { "air" },
+--     interval  = 0.2,
+--     chance    = 0,
+--     action    = function(pos, node, active_object_count, active_object_count_wider)
+--         --internal.add_node_to_check(pos)
+--     end
+-- })
 
 dofile(modpath .. "/physics.lua")

internal.lua

@@ -83,6 +83,9 @@ function internal.new_lpn(hash, pos)
         liquid_id = liquid_id,
         init_liquid_level = liquid_level,
         liquid_level = liquid_level,
+        density = 0,
+        gradient = { x = 0, y = 0, z = 0 },
+        neighbors = {},
     }
 end
 
@@ -106,7 +109,8 @@ end
 -- @param pos table Position of the node
 function internal.add_node_to_check(pos)
     local h = core.hash_node_position(pos)
-    liquid_physics._nodes_to_check[h] = pos
+    local lpn = internal.new_lpn(h, pos)
+    liquid_physics._nodes_to_check[h] = lpn
 end
 
 -- This node will no longer be checked

physics.lua

@@ -17,12 +17,30 @@ local modpath = core.get_modpath(core.get_current_modname())
 local internal = dofile(modpath .. "/internal.lua")
 
 -- A table of offsets for ease of use
-local offsets = {
-    { x = 0,  z = 1, },
-    { x = 0,  z = -1, },
-    { x = 1,  z = 0, },
-    { x = -1, z = 0, }
-}
+local offsets = {}
+-- local offsets = {
+--     { x = 0,  z = 0,  y = 0, d = 0 },
+
+--     { x = 0,  z = 1,  y = 0, d = 1 },
+--     { x = 0,  z = -1, y = 0, d = 1 },
+
+--     { x = 1,  z = 0,  y = 0, d = 1 },
+--     { x = -1, z = 0,  y = 0, d = 1 },
+-- }
+for x = -1, 1 do
+    for y = -1, 1 do
+        for z = -1, 1 do
+            local d = math.abs(x) + math.abs(y) + math.abs(z)
+            table.insert(offsets, {
+                x = x, -- X Offset
+                y = y, -- Y Offset
+                z = z, -- Z Offset
+                d = d  -- Distance to 0 / 0 / 0
+            })
+        end
+    end
+end
+
 -- Store number of offsets for less calculations
 local number_of_offsets = table.getn(offsets)
 
@@ -33,8 +51,8 @@ local number_of_offsets = table.getn(offsets)
 local function add_offset_to_pos(pos, offset)
     return {
         x = pos.x + offset.x,
+        y = pos.y + offset.y,
         z = pos.z + offset.z,
-        y = pos.y
     }
 end
 
@@ -52,6 +70,16 @@ local function get_lpn_buffered(b, pos)
     return b[h]
 end
 
+local function round_away_from_zero(value)
+    if value == 0 then
+        return 0
+    end
+    if value > 0 then
+        return math.ceil(value)
+    end
+    return math.floor(value) -- Let's hope math floor is optimized for zero
+end
+
 -- Checks if liquid_id of curr and lpn are the same.
 -- Checks if the liquid_level is above -1
 -- @param curr table The current LPN
@@ -61,25 +89,203 @@ local function is_lpn_relevant(curr, lpn)
     return lpn.liquid_level >= 0 and (lpn.liquid_level == 0 or curr.liquid_id == lpn.liquid_id)
 end
 
+-- local function get_gradient(base, compare, opp)
+--     local compare_copy = compare
+--     if compare_copy < 0 then compare_copy = 0 end
+--     return math.ceil(((opp + base) - compare_copy * 2) / 8)
+-- end
+
 -- Gets all adjacent liquid nodes with the same liquid_id as curr
 -- Gets all adjacent air nodes
 -- @param b     table  Buffered LPN
 -- @param curr  table  The current LPN
 -- @return      table  Table of neighboring LPN
 -- @return      number Number of neighbors
-local function get_valid_neighbors(b, curr)
+local function get_all_neighbors_pressure(b, curr)
     local neighbors = {}
-    local number_of_neighbors = 0
+    local no_of_h_neighbors = 0
+    local no_of_v_neighbors = 0
     for i = 1, number_of_offsets do
-        local pos = add_offset_to_pos(curr.pos, offsets[i])
+        local current_offset = offsets[i]
+        local pos = add_offset_to_pos(curr.pos, current_offset)
         local lpn = get_lpn_buffered(b, pos)
 
-        if is_lpn_relevant(curr, lpn) then
-            number_of_neighbors = number_of_neighbors + 1
-            table.insert(neighbors, math.random(number_of_neighbors, 1), lpn)
+        --if is_lpn_relevant(curr, lpn) then
+
+        local o_off = {}
+        if i % 2 == 0 then
+            o_off = offsets[i - 1]
+        else
+            o_off = offsets[i + 1]
+        end
+
+        local o_pos = add_offset_to_pos(curr.pos, o_off)
+        local o_lpn = get_lpn_buffered(b, o_pos)
+
+        local g = current_offset.g + get_gradient(curr.liquid_level, lpn.liquid_level, o_lpn.liquid_level)
+
+        if g ~= 0 then
+            if i < 5 then
+                no_of_h_neighbors = no_of_h_neighbors + 1
+            else
+                no_of_v_neighbors = no_of_v_neighbors + 1
+            end
+        end
+        table.insert(neighbors, { lpn = lpn, g = g })
+        --end
+    end
+    return neighbors, no_of_h_neighbors, no_of_v_neighbors
+end
+
+
+local function get_pressure_gradient(b, lpn)
+    local number_of_directions = 0
+
+    lpn.neighbors = get_all_neighbors_pressure(b, lpn)
+
+    lpn.pressure_gradient = internal.get_inital_pressure_gradient()
+
+    local i = 1
+    for _, g in pairs(lpn.pressure_gradient) do
+        g = g + get_gradient(lpn.liquid_level, lpn.neighbors[i].liquid_level)
+        i = i + 1
+        if g ~= 0 then
+            number_of_directions = number_of_directions + 1
         end
     end
-    return neighbors, number_of_neighbors
+
+    return number_of_directions
+end
+
+local function get_density_influence(r, d)
+    local vol = math.pi * (r ^ 8) / 4
+    local v = math.max(0, r - d)
+    return v + v * v / vol
+end
+
+local function get_density_influence_derivative(r, d)
+    if (d >= r) then return 0 end
+    local f = r * r - d * d
+    local scale = -24 / (math.pi * (r ^ 8))
+    return scale * d * f * f
+end
+
+local function get_density(b, lpn)
+    local radius = 3 -- 3 is max
+    for i = 1, number_of_offsets do
+        local offset = offsets[i]
+        local o_pos = add_offset_to_pos(lpn.pos, offset)
+        local o_lpn = get_lpn_buffered(b, o_pos)
+
+        local liquid_level = o_lpn.liquid_level
+        if liquid_level < 0 then
+            liquid_level = lpn.liquid_level
+        elseif liquid_level == 0 then
+            liquid_level = 0
+        end
+
+        -- if offset.d == 0 then
+        --     liquid_level = 0
+        -- end
+
+        local influence = liquid_level * get_density_influence(radius, offset.d)
+
+        table.insert(lpn.neighbors, { lpn = o_lpn, prs = 0 })
+
+        lpn.density = lpn.density + influence
+    end
+    lpn.density = math.floor(lpn.density)
+end
+
+
+local function get_pressure_from_density(density)
+    local multiplier = 1
+    local target_pressure = 11
+    --core.chat_send_all(density)
+    return (density - target_pressure) * multiplier
+end
+
+local function get_gradient(b, lpn)
+    -- local gradient = {
+    --     x = 0,
+    --     y = 0,
+    --     z = 0,
+    -- }
+    local radius = 3 -- 3 is max
+
+    for i = 1, number_of_offsets do
+        local offset = offsets[i]
+
+        if offset.d == 0 then
+            goto continue
+        end
+
+        local neighbor = lpn.neighbors[i].lpn
+
+        local density = neighbor.density
+
+        -- if density < 0 then
+        --     density = neighbor.density
+        -- else
+        if density == 0 then
+            density = 1
+        end
+
+        local slope = get_density_influence_derivative(radius, offset.d)
+        local pressure = get_pressure_from_density(density)
+
+        --if offset.y == 0 then
+        lpn.neighbors[i].prs = math.ceil(math.abs(
+            (pressure * slope * lpn.liquid_level / density)))
+
+        lpn.neighbors[i].is_down = false
+
+        if offset.y == 1 then
+            lpn.neighbors[i].prs = lpn.neighbors[i].prs - 6
+        end
+
+        if offset.y == -1 then
+            lpn.neighbors[i].prs = 1
+            lpn.neighbors[i].is_down = true
+        end
+
+        -- lpn.gradient = {
+        --     x = lpn.gradient.x + (pressure * offset.x * slope * neighbor.liquid_level / density),
+        --     y = lpn.gradient.y + (pressure * offset.y * slope * neighbor.liquid_level / density),
+        --     z = lpn.gradient.z + (pressure * offset.z * slope * neighbor.liquid_level / density),
+        -- }
+        ::continue::
+    end
+
+    --core.chat_send_all("Pressure: " .. dump(lpn.gradient))
+
+    -- lpn.gradient = {
+    --     x = round_away_from_zero(lpn.gradient.x),
+    --     y = round_away_from_zero(lpn.gradient.y),
+    --     z = round_away_from_zero(lpn.gradient.z),
+    -- }
+    -- if lpn.gradient.x > 0 then
+    --     lpn.gradient.x = 1
+    -- elseif lpn.gradient.x < 0 then
+    --     lpn.gradient.x = -1
+    -- end
+
+    -- if lpn.gradient.y > 0 then
+    --     lpn.gradient.y = 1
+    -- elseif lpn.gradient.y < 0 then
+    --     lpn.gradient.y = -1
+    -- end
+
+    -- if lpn.gradient.z > 0 then
+    --     lpn.gradient.z = 1
+    -- elseif lpn.gradient.z < 0 then
+    --     lpn.gradient.z = -1
+    -- end
+end
+
+
+local function get_pressure_force(lpn)
+
 end
 
 -- Gets neighbors of curr and calculates the pressure
@@ -127,6 +333,9 @@ local function try_move(from, to, amount)
     if to.liquid_level >= 8 then
         return 0
     end
+    if amount <= 0 then
+        return 0
+    end
     local max_allowed = amount + 8 - (to.liquid_level + amount)
     local max_allowed_clamped = math.min(max_allowed, amount, from.liquid_level)
 
@@ -212,20 +421,179 @@ local function move(b, curr_pos)
     end
 end
 
-core.register_on_mapblocks_changed(function(modified_blocks, modified_blocks_count)
-    -- Buffered LPN
-    local b = {}
-    for hpos, pos in pairs(liquid_physics._nodes_to_check) do
-        if core.compare_block_status(pos, "active") then
-            move(b, pos)
-        else
-            internal.remove_node_to_check(pos)
-        end
+local function try_spread(buffer, from, to, is_down)
+    if is_lpn_relevant(from, to) and ((from.liquid_level > 1 and from.liquid_level >= to.liquid_level + 1) or is_down) then
+        return try_move(from, to, 1)
     end
-    -- Update only changed nodes from buffer
-    for _, lpn in pairs(b) do
-        if lpn.init_liquid_level ~= lpn.liquid_level then
-            internal.set_node(lpn)
+    return 0
+end
+
+local function shuffle(array)
+    math.randomseed(os.time())                  -- Seed the random number generator
+    for i = #array, 2, -1 do
+        local j = math.random(i)                -- Pick a random index from 1 to i
+        array[i], array[j] = array[j], array[i] -- Swap elements
+    end
+end
+
+local last_finish = 0
+local active_blocks = {}
+
+core.register_on_liquid_transformed(function(pos_list, node_list)
+    for hash, block_start in pairs(active_blocks) do
+        if core.compare_block_status(block_start, "active") then
+        else
+            active_blocks[hash] = nil
+            goto continue
         end
+
+        --core.chat_send_all(dump(block_start) .. "----" .. modified_blocks_count)
+        local buffer = {}
+        local block_end = {
+            x = block_start.x + 15,
+            y = block_start.y + 15,
+            z = block_start.z + 15,
+        }
+        local node_pos_list = core.find_nodes_in_area(block_start, block_end, { "group:liquid_physics" })
+
+        local lpn_list = {}
+        local number_of_lpn = 0
+        for _, pos in pairs(node_pos_list) do
+            local lpn = get_lpn_buffered(buffer, pos)
+            get_density(buffer, lpn)
+
+            table.insert(lpn_list, lpn)
+            number_of_lpn = number_of_lpn + 1
+        end
+
+        for i = 1, number_of_lpn do
+            local g_lpn = lpn_list[i]
+            get_gradient(buffer, g_lpn)
+
+            --g_lpn.gradient.y = 0
+
+            --core.chat_send_all("Grad: " .. dump(g_lpn.gradient))
+
+            -- local spread_to_pos = add_offset_to_pos(g_lpn.pos, g_lpn.gradient)
+            -- local spread_to = get_lpn_buffered(buffer, spread_to_pos)
+
+            -- try_spread(buffer, g_lpn, spread_to)
+
+
+
+            -- local gs = 0
+            -- for g = 1, number_of_offsets do
+            --     if g_lpn.neighbors[g].prs > 0 then
+            --         gs = gs + 1
+            --     end
+            -- end
+            local number_of_targets = 0
+            for g = 1, number_of_offsets do
+                if g_lpn.neighbors[g].prs > 0 and not g_lpn.neighbors[g].is_down then
+                    number_of_targets = number_of_targets + 1
+                end
+            end
+
+            if number_of_targets >= g_lpn.liquid_level then
+                shuffle(g_lpn.neighbors)
+            end
+
+            for g = 1, number_of_offsets do
+                if g_lpn.neighbors[g].prs > 0 then
+                    try_spread(buffer, g_lpn, g_lpn.neighbors[g].lpn, g_lpn.neighbors[g].is_down)
+                end
+            end
+
+
+            -- if g_lpn.gradient.x ~= 0 then
+            --     local spread_to_pos = add_offset_to_pos(g_lpn.pos, { x = g_lpn.gradient.x, y = 0, z = 0 })
+            --     local spread_to = get_lpn_buffered(buffer, spread_to_pos)
+
+            --     try_spread(buffer, g_lpn, spread_to)
+            --     -- if try_spread(buffer, g_lpn, spread_to, gs) == 0 then
+            --     --     spread_to_pos = add_offset_to_pos(g_lpn.pos, { x = g_lpn.gradient.x * -1, y = 0, z = 0 })
+            --     --     spread_to = get_lpn_buffered(buffer, spread_to_pos)
+            --     --     try_spread(buffer, g_lpn, spread_to, gs)
+            --     -- end
+            -- end
+            -- if g_lpn.gradient.z ~= 0 then
+            --     local spread_to_pos = add_offset_to_pos(g_lpn.pos, { x = 0, y = 0, z = g_lpn.gradient.z })
+            --     local spread_to = get_lpn_buffered(buffer, spread_to_pos)
+
+            --     try_spread(buffer, g_lpn, spread_to)
+            --     -- if try_spread(buffer, g_lpn, spread_to, gs) == 0 then
+            --     --     spread_to_pos = add_offset_to_pos(g_lpn.pos, { x = 0, y = 0, z = g_lpn.gradient.z * -1 })
+            --     --     spread_to = get_lpn_buffered(buffer, spread_to_pos)
+            --     --     try_spread(buffer, g_lpn, spread_to, gs)
+            --     -- end
+            -- end
+        end
+
+        if lpn_list[1] ~= nil then
+        end
+
+        -- for _, pos in pairs(node_pos_list) do
+        --     local lpn = get_lpn_buffered(buffer, pos)
+
+        --     local neighbors, h, v = get_all_neighbors_pressure(buffer, lpn)
+
+        --     local n = 0
+        --     for i = 1, number_of_offsets do
+        --         if neighbors[i].g == 0 then
+        --             goto continue
+        --         end
+        --         if i < 5 then
+        --             n = h
+        --         else
+        --             n = v - 1
+        --         end
+        --         try_spread(buffer, lpn, neighbors[i].lpn, n, neighbors[i].g)
+        --         ::continue::
+        --     end
+        -- end
+
+        -- ::continue::
+        --
+        for _, lpn in pairs(buffer) do
+            if lpn.init_liquid_level ~= lpn.liquid_level then
+                if lpn.liquid_id then
+                    internal.set_node(lpn)
+                end
+            end
+        end
+        ::continue::
     end
 end)
+
+core.register_on_mapblocks_changed(function(modified_blocks, modified_blocks_count)
+    for hash, _ in pairs(modified_blocks) do
+        local block_start = core.get_position_from_hash(hash)
+
+        block_start = {
+            x = block_start.x * 16,
+            y = block_start.y * 16,
+            z = block_start.z * 16,
+        }
+
+        if core.compare_block_status(block_start, "active") then
+            active_blocks[hash] = block_start
+        else
+            active_blocks[hash] = nil
+        end
+    end
+    -- -- Buffered LPN
+    -- local b = {}
+    -- for hpos, pos in pairs(liquid_physics._nodes_to_check) do
+    --     if core.compare_block_status(pos, "active") then
+    --         move(b, pos)
+    --     else
+    --         internal.remove_node_to_check(pos)
+    --     end
+    -- end
+    -- -- Update only changed nodes from buffer
+    -- for _, lpn in pairs(b) do
+    --     if lpn.init_liquid_level ~= lpn.liquid_level then
+    --         internal.set_node(lpn)
+    --     end
+    -- end
+end)