HC/spatialhash.lua

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--[[
Copyright (c) 2011 Matthias Richter
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
Except as contained in this notice, the name(s) of the above copyright holders
shall not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
]]--
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local floor = math.floor
local min, max = math.min, math.max
local _PACKAGE = (...):match("^(.+)%.[^%.]+")
if not (common and common.class and common.instance) then
class_commons = true
require(_PACKAGE .. '.class')
end
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local Spatialhash = {}
function Spatialhash:init(cell_size)
self.cell_size = cell_size or 100
self.cells = {}
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end
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function Spatialhash:cellCoords(x,y)
return floor(x / self.cell_size), floor(y / self.cell_size)
end
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function Spatialhash:cell(i,k)
local row = rawget(self.cells, i)
if not row then
row = {}
rawset(self.cells, i, row)
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end
local cell = rawget(row, k)
if not cell then
cell = setmetatable({}, {__mode = "kv"})
rawset(row, k, cell)
end
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return cell
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end
function Spatialhash:cellAt(x,y)
return self:cell(self:cellCoords(x,y))
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end
function Spatialhash:inRange(x1,y1, x2,y2)
local set = {}
x1, y1 = self:cellCoords(x1, y1)
x2, y2 = self:cellCoords(x2, y2)
for i = x1,x2 do
for k = y1,y2 do
for obj in pairs(self:cell(i,k)) do
rawset(set, obj, obj)
end
end
end
return set
end
function Spatialhash:rangeIter(...)
return pairs(self:inRange(...))
end
function Spatialhash:insert(obj, x1, y1, x2, y2)
x1, y1 = self:cellCoords(x1, y1)
x2, y2 = self:cellCoords(x2, y2)
for i = x1,x2 do
for k = y1,y2 do
rawset(self:cell(i,k), obj, obj)
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end
end
end
function Spatialhash:remove(obj, x1, y1, x2,y2)
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-- no bbox given. => must check all cells
if not (x1 and y1 and x2 and y2) then
for _,row in pairs(self.cells) do
for _,cell in pairs(row) do
rawset(cell, obj, nil)
end
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end
return
end
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-- else: remove only from bbox
x1,y1 = self:cellCoords(x1,y1)
x2,y2 = self:cellCoords(x2,y2)
for i = x1,x2 do
for k = y1,y2 do
rawset(self:cell(i,k), obj, nil)
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end
end
end
-- update an objects position
function Spatialhash:update(obj, old_x1,old_y1, old_x2,old_y2, new_x1,new_y1, new_x2,new_y2)
old_x1, old_y1 = self:cellCoords(old_x1, old_y1)
old_x2, old_y2 = self:cellCoords(old_x2, old_y2)
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new_x1, new_y1 = self:cellCoords(new_x1, new_y1)
new_x2, new_y2 = self:cellCoords(new_x2, new_y2)
if old_x1 == new_x1 and old_y1 == new_y1 and
old_x2 == new_x2 and old_y2 == new_y2 then
return
end
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for i = old_x1,old_x2 do
for k = old_y1,old_y2 do
rawset(self:cell(i,k), obj, nil)
end
end
for i = new_x1,new_x2 do
for k = new_y1,new_y2 do
rawset(self:cell(i,k), obj, obj)
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end
end
end
function Spatialhash:draw(how, show_empty, print_key)
if show_empty == nil then show_empty = true end
for k1,v in pairs(self.cells) do
for k2,cell in pairs(v) do
local empty = true
(function() for _ in pairs(cell) do empty = false; return end end)()
if show_empty or not empty then
local x = k1 * self.cell_size
local y = k2 * self.cell_size
love.graphics.rectangle(how or 'line', x,y, self.cell_size, self.cell_size)
if print_key then
love.graphics.print(("%d:%d"):format(k1,k2), x+3,y+3)
end
end
end
end
end
return common.class('Spatialhash', Spatialhash)