spatial grid initial

lib/spatial_grid.lua

@@ -0,0 +1,69 @@
+require "lib.vec3"
+require "lib.math2"
+require "lib.entity"
+require "math"
+
+local __SpatialGrid = {
+    table = {}
+}
+
+---- uncomment this for test
+-- __Entity = {
+--     position = Vec3 {},
+--     some_other_shit = "this litteraly other shit"
+-- }
+
+-- function Entity(pos)
+--     local entity = {
+--         position = pos
+--     }
+
+--     return setmetatable(entity, {__index = __Entity})
+-- end
+
+
+function SpatialGrid(center, side, cell_size, entities)
+    local lu_side = Vec3 {center.x - math.ceil(side/2), center.y - math.ceil(side/2)}
+    local rd_side = Vec3 {center.x + math.floor(side/2), center.y + math.floor(side/2)}
+
+    local pos_entities = {}
+    for _, entity in ipairs(entities) do
+        local pos = tostring(math.step_floor(entity.position.x, cell_size)) .. " " .. tostring(math.step_floor(entity.position.y, cell_size))
+        if pos_entities[pos] == nil then
+            pos_entities[pos] = {}
+        end
+        table.insert(pos_entities[pos], entity)
+    end
+
+    table = {}
+    for x = lu_side.x, rd_side.x, cell_size do
+        for y = lu_side.y, rd_side.y, cell_size do
+            local pos = tostring(x) .. " " .. tostring(y)
+            table[pos] = {position = Vec3 {x, y}, content = pos_entities[pos]}
+        end
+    end
+
+    return setmetatable({table = table}, {__index = __SpatialGrid})  -- честно не уверен зачем это, но пусть будет
+end
+
+function __SpatialGrid:query(position)
+    local entities = {}
+    for extra_x = -1, 1 do
+        for extra_y = -1, 1 do
+            local entity_pos = tostring(position.x + extra_x) .. " " .. tostring(position.y + extra_y)
+            entities[entity_pos] = self.table[entity_pos].content
+        end
+    end
+    return entities
+end
+
+---- uncomment this too for test
+-- local table = SpatialGrid(Vec3 {0, 0}, 10, 0.5, {Entity(Vec3 {-1, -1, 0}), Entity(Vec3 {-1.5, -1, 0}), Entity(Vec3 {-2, -1, 0})})
+
+-- local query_table = table:query(Vec3 {-1, -1, 0})
+
+-- for k, v in pairs(query_table) do
+--     for i = 1, #v do
+--         print(v[i].some_other_shit, v[i].position.y)
+--     end
+-- end