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Improve performance of navigational functions #5861

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merged 2 commits into from
Jan 27, 2024
Merged

Improve performance of navigational functions #5861

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e147afb
Improve performance of navigational functions
Garanas Jan 27, 2024
d838996
Fix typo
Garanas Jan 27, 2024
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130 changes: 59 additions & 71 deletions lua/sim/NavUtils.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -311,6 +311,12 @@ local function FindLeaf(grid, position)
return leaf
end

---@type NavSection[]
local NavSectionCache = { }

---@type NavSection[]
local NavSectionStack = { }

---@param grid NavGrid
---@param position Vector
---@return NavSection | nil
Expand All @@ -324,18 +330,20 @@ local function FindSection(grid, position)
return NavGenerator.NavSections[leaf.Section]
end

--- Retrieves all sections within the given radius.
---@param grid NavGrid
---@param position Vector
---@param distance number
---@return Vector[] | nil
---@param cache NavSection[] # Cache to store the intermediate results in
---@return NavSection[] | nil
---@return number | ('NotGenerated'| 'OutsideMap' | 'NoResults')?
local function FindSections(grid, position, distance)
local function FindSections(grid, position, distance, cache)
-- check if generated
if not NavGenerator.IsGenerated() then
return nil, 'NotGenerated'
end

-- setup pathing
-- setup search
local seenIdentifier = PathToGetUniqueIdentifier()
local sectionOrigin = FindSection(grid, position)

Expand All @@ -344,7 +352,6 @@ local function FindSections(grid, position, distance)
return nil, 'OutsideMap'
end

-- local scope for performance
-- local scope for performance
local NavSections = NavGenerator.NavSections
local ox = position[1]
Expand All @@ -353,9 +360,15 @@ local function FindSections(grid, position, distance)
-- 0th iteration of search
sectionOrigin.HeapIdentifier = seenIdentifier

local stack = NavSectionStack
stack[1] = sectionOrigin
local current = 1
local stack = { sectionOrigin }
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@Garanas Garanas Jan 27, 2024 •
edited

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Instead of creating new tables for each function call we use a cache that is provided to us by the function parameters.

This is an internal function (note the 'local' keyword). Therefore we have full control over the cache.

local candidates = { sectionOrigin.Center }

cache[1] = sectionOrigin
local head = 1

-- allows us to skip the square root
local distanceSquared = distance * distance

while current > 0 do
local section = stack[current]
Expand All @@ -366,36 +379,30 @@ local function FindSections(grid, position, distance)
for k = 1, TableGetn(neighbors) do
local neighbor = NavSections[neighbors[k]]
if neighbor.HeapIdentifier != seenIdentifier then
-- flag the neighbor as seen
neighbor.HeapIdentifier = seenIdentifier

candidates[neighbor.Identifier] = neighbor.Center
-- store the neighbor in the cache
cache[head] = neighbor
head = head + 1

-- if neighbor exceeds the distance then we pick the neighbor
local dx = ox - neighbor.Center[1]
local dz = oz - neighbor.Center[3]
if MathSqrt(dx * dx + dz * dz) < distance then
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We can skip the square root by squaring the distance.

-- always include it
-- flag the neighbor as the next place to search
local neighborCenter = neighbor.Center
local dx = ox - neighborCenter[1]
local dz = oz - neighborCenter[3]
if dx * dx + dz * dz < distanceSquared then
current = current + 1
stack[current] = neighbor
end
end
end
end

local head = 1

---@type Vector[]
local positions = { }
for _, center in candidates do
positions[head] = center
head = head + 1
end

if head == 1 then
return nil, 'NoResults'
end

return positions, head - 1
return cache, head - 1
end

---@param destination NavLeaf
Expand Down Expand Up @@ -1067,19 +1074,14 @@ function GetTerrainLabel(layer, position)
return GetTerrainLabelXZ(layer, position[1], position[3])
end

---@type NavTree[]
local GetPositionsInRadiusCandidates = {}
local GenericResultsCache = { }
local GenericQueueCache = { }

---@param layer NavLayers
---@param position Vector
---@param distance number
---@param thresholdSize? number
---@param cache? Vector[]
---@return Vector[] | nil
---@return number | ('NotGenerated' | 'InvalidLayer' | 'OutsideMap' | 'SystemError' | 'Unpathable' | 'NoData')?
---@return number | ('NotGenerated' | 'InvalidLayer' | 'OutsideMap' | 'SystemError' | 'Unpathable' | 'NoData' | 'NoResults')?
function GetPositionsInRadius(layer, position, distance, thresholdSize, cache)

-- check layer argument
local grid = FindGrid(layer)
if not grid then
Expand All @@ -1092,35 +1094,27 @@ function GetPositionsInRadius(layer, position, distance, thresholdSize, cache)
end

-- find surrounding points of interest
local points, count = FindSections(gridAir, position, distance)
if not points then
local sections, count = FindSections(gridAir, position, distance, NavSectionCache)
if not sections then
local msg = count --[[@as string]]
return nil, msg
end

-- use the cache
-- try and use the cache
local head = 1
cache = cache or { }

for k, point in points do
local section = FindSection(grid, point)
if not section then
continue
end

-- transform sections into positions
for k, section in sections do
cache[head] = section.Center
head = head + 1
end

-- clean up remainder of the cache
-- clear up remainder of the cache
for k = head, TableGetn(cache) do
cache[k] = nil
end

if head == 1 then
return nil, 'NoResults'
end

return cache, head - 1
end

Expand Down Expand Up @@ -1155,9 +1149,10 @@ end
---@param layer NavLayers
---@param origin Vector
---@param distance number
---@param cache? Vector[]
---@return Vector[] | nil
---@return number | ('NotGenerated' | 'OutsideMap' | 'NoResults' | 'InvalidLayer')
function DirectionsFrom(layer, origin, distance)
function DirectionsFrom(layer, origin, distance, cache)
-- check if generated
if not NavGenerator.IsGenerated() then
return nil, 'NotGenerated'
Expand All @@ -1170,39 +1165,38 @@ function DirectionsFrom(layer, origin, distance)
end

-- compute directions
local points, count = FindSections(grid, origin, distance)
if not points then
local sections, count = FindSections(grid, origin, distance, NavSectionCache)
if not sections then
local msg = count --[[@as string]]
return nil, msg
end

-- only keep those at the edge
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Add the possibility for the user to provide a cache to prevent table allocations.

-- try and use the cache for performance
local head = 1
cache = cache or { }

-- only keep sections that are on the edge
local ox = origin[1]
local oz = origin[3]
local ds = distance * distance
local head = 1
for k = 1, count do

local point = points[k]
local point = sections[k].Center
local dx = ox - point[1]
local dz = oz - point[3]

if dx * dx + dz * dz > ds then
points[head] = point
cache[head] = point
head = head + 1
end
end

if head == 1 then
return nil, 'NoResults'
end

-- clear out remaining points
for k = count, head, -1 do
points[k] = nil
-- clear up remainder of the cache
for k = head, TableGetn(cache) do
cache[k] = nil
end

return points, head - 1
return cache, head - 1
end

--- Computes a list of waypoints that represent random directions that we can navigate to
Expand Down Expand Up @@ -1230,24 +1224,22 @@ function DirectionsFromWithThreatThreshold(layer, origin, distance, aibrain, thr
end

-- compute directions
local points, count = FindSections(grid, origin, distance)
if not points then
local sections, count = FindSections(grid, origin, distance, NavSectionCache)
if not sections then
local msg = count --[[@as string]]
return nil, msg, nil, nil
end

-- no locations found
if count == 0 then
return nil, 'NoResults', nil, nil
end

local tHead = 1
---@type BrainPositionThreat[]
local threats = { }
local tHead = 1

---@type Vector[]
local points = { }
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This should be cacheable via a parameter too, but we'll keep that for the next pull request 😃

local head = 1

for k = 1, count do
local point = points[k]
local point = sections[k].Center
local threat = threatFunc(aibrain, point, threatRadius)
if threat < threatThreshold then
points[head] = point
Expand All @@ -1263,10 +1255,6 @@ function DirectionsFromWithThreatThreshold(layer, origin, distance, aibrain, thr
return nil, 'TooMuchThreat', threats, tHead - 1
end

for k = head, count do
points[k] = nil
end

return points, head - 1, threats, tHead - 1
end

Expand Down