实体建模

local GeometryService = game:GetService("GeometryService")

local function fragmentAtPosition(player, part, contactPoint, radius)
	local allSites = GeometryService:GenerateFragmentSites(part, {Origin = contactPoint, Radius = radius})

	local success, fragments = pcall(function()
		return GeometryService:FragmentAsync(part, allSites)
	end)
	if not success then
		warn("碎片化失败:"..tostring(fragments))
		return
	end

	local decals = {}
	for _,child in pairs(part:GetChildren()) do
		if child:IsA("Decal") or child:IsA("SurfaceAppearance") then
			table.insert(decals,child)
		end
	end
	
	for i = 1, #fragments do
		local fragment = fragments[i].Instance
		if fragment == nil then
			continue
		end
		
		for _,d in pairs(decals) do
			local d2 = d:Clone()
			d2.Parent = fragment
		end

		fragment.Anchored = false
		fragment.Parent = part.Parent
		fragment:SetNetworkOwner(player)
	end

	if #fragments ~= 0  then
		part:Destroy()
	end
	
	return fragments
end

local GeometryService = game:GetService("GeometryService")

local function fragmentWithinStencil(player, part)
	local overlapParams = OverlapParams.new()
	overlapParams.FilterType = Enum.RaycastFilterType.Include
	overlapParams.FilterDescendantsInstances = {workspace.Stencil}
	overlapParams.RespectCanCollide = false
	
	local sensor = Instance.new("Part")
	sensor.Size = Vector3.new(0.01, 0.01, 0.01)
	
	local allSites = GeometryService:GenerateFragmentSites(part, {SiteSpacing = 0.9})

	local fragmentSites = {}
	local mainPartSites = {}
	for _, site in ipairs(allSites) do
		sensor.CFrame = CFrame.new(site)
		local partsFound = workspace:GetPartsInPart(sensor, overlapParams)

		if #partsFound > 0 then
			table.insert(fragmentSites, site)
		else
			table.insert(mainPartSites, site)
		end
	end

	local sortedSites = fragmentSites
	table.insert(sortedSites, mainPartSites)

	workspace.Stencil:Destroy()

	local success, fragments = pcall(function()
		return GeometryService:FragmentAsync(part, sortedSites, {SplitApart = false})
	end)
	if not success then
		warn("碎片化失败:"..tostring(fragments))
		return
	end
	
	local decals = {}
	for _,child in pairs(part:GetChildren()) do
		if child:IsA("Decal") or child:IsA("SurfaceAppearance") then
			table.insert(decals,child)
		end
	end
	
	for i = 1, #fragments do
		local fragment = fragments[i].Instance
		if fragment == nil then
			continue
		end
		
		for _,d in pairs(decals) do
			local d2 = d:Clone()
			d2.Parent = fragment
		end

		fragment.Anchored = false
		fragment.Parent = part.Parent
		fragment:SetNetworkOwner(player)
	end

	if #fragments ~= 0  then
		part:Destroy()
	end
	
	return fragments
end

local GeometryService = game:GetService("GeometryService")

local function fragmentCrossPart(player, part, contactPoint, radius)
	local allSites = GeometryService:GenerateFragmentSites(part, {Origin = contactPoint, Radius = radius})

	local fragmentsSorted = {}
	for i = 1, #allSites do
		fragmentsSorted[i] = {}
	end
	
	local partsFound = workspace:GetPartBoundsInRadius(contactPoint, radius)
	for i, part in ipairs(partsFound) do

		local success, fragments = pcall(function()
			return GeometryService:FragmentAsync(part, allSites)
		end)
		if not success then
			warn("碎片化失败:"..tostring(fragments))
			return
		end
		
		for i = 1, #fragments do
			local fragment = fragments[i].Instance
			local siteIndex = fragments[i].Index
			if fragment == nil or siteIndex == nil then
				continue
			end
			
			table.insert(fragmentsSorted[siteIndex], fragment)
		end
	end
	
	for i = 1, #fragmentsSorted do
		local fragmentList = fragmentsSorted[i]
		if #fragmentList == 0 then
			continue
		end
		
		if #fragmentList == 1 then
			local fragment = fragmentList[1]
			fragment.Anchored = false
			fragment.Parent = part.Parent
			fragment:SetNetworkOwner(player)
			continue
		end
		
		if i == #allSites then
			for j = 1, #fragmentList do
				local fragment = fragmentList[j]
				fragment.Parent = part.Parent
				fragment.Anchored = true
			end
			continue
		end
		
		local mainPart = fragmentList[1]
		local otherParts = {}
		for j = 2, #fragmentList do
			table.insert(otherParts, fragmentList[j])
		end
		
		local success, results = pcall(function()
			return GeometryService:UnionAsync(mainPart, otherParts)
		end)
		if not success then
			warn("联合失败:"..tostring(results))
			return
		end
		
		for j = 1, #results do
			results[j].Parent = part.Parent
			results[j].Anchored = false
			results[j]:SetNetworkOwner(player)
		end
	end
	
	for i, part in ipairs(partsFound) do
		part:Destroy()
	end
end

local function generateFragmentSites(part: BasePart, siteSpacing: number?, origin: Vector3?, radius: number?): {Vector3}
	local RANDOMNESS_MULTIPLIER = 1.0 -- 用于调整抖动量
	
	if (origin and not radius) or (radius and not origin) then
		warn("必须提供原点和半径，或者都不提供。")
		return {}
	end
	
	local isLocalized = (radius ~= nil) -- isLocalized 意味着不碎片化整个零件，只碎片化一部分。
	local partCFrame = part.ExtentsCFrame
	local gridDimensions: Vector3
	local localGridCenter: Vector3
	
	local spacing
	if siteSpacing then
		spacing = siteSpacing
	elseif isLocalized then
		spacing = radius * 0.5
	else
		local partSize = part.Size
		local volume = partSize.X * partSize.Y * partSize.Z
		spacing = (volume / 5) ^ (1/3)
	end
	
	if isLocalized then
		local localOrigin = partCFrame:PointToObjectSpace(origin)
		local gridSize = math.ceil(radius * 2 / spacing) + 3
		gridDimensions = Vector3.new(gridSize, gridSize, gridSize)
		localGridCenter = localOrigin
	else
		local partSize: Vector3 = part.Size
		local xCount = math.ceil(partSize.X / spacing)
		local yCount = math.ceil(partSize.Y / spacing)
		local zCount = math.ceil(partSize.Z / spacing)

		gridDimensions = Vector3.new(xCount, yCount, zCount)
		localGridCenter = Vector3.zero
	end
	
	local totalGridSize = gridDimensions * spacing
	local halfCell = Vector3.new(spacing, spacing, spacing) * 0.5
	local localStartOffset = localGridCenter - (totalGridSize * 0.5) + halfCell
	
	local innerJitter = spacing * 0.5 * RANDOMNESS_MULTIPLIER
	local outerJitter = math.min(spacing * 0.5 * 0.866, innerJitter)

	local sitesFlatList = {}

	for x = 0, gridDimensions.X - 1 do
		for y = 0, gridDimensions.Y - 1 do
			for z = 0, gridDimensions.Z - 1 do

				local isOuterShell =
					x == 0 or x == gridDimensions.X - 1 or
					y == 0 or y == gridDimensions.Y - 1 or
					z == 0 or z == gridDimensions.Z - 1
				local jitterAmount = if (isOuterShell and isLocalized) then outerJitter else innerJitter
				
				local jitterOffset = Vector3.new(
					(math.random() - 0.5) * 2 * jitterAmount,
					(math.random() - 0.5) * 2 * jitterAmount,
					(math.random() - 0.5) * 2 * jitterAmount
				)

				local offsetInGrid = Vector3.new(x, y, z) * spacing

				table.insert(sitesFlatList, localStartOffset + offsetInGrid + jitterOffset)
			end
		end
	end

	local sitesListFinal = {}
	
	if isLocalized then
		local mainPartSites = {}

		for _, localSite in ipairs(sitesFlatList) do
			local worldSite = partCFrame * localSite
			local distance = (worldSite - origin).Magnitude
			if distance < radius then
				table.insert(sitesListFinal, worldSite)
			else
				table.insert(mainPartSites, worldSite)
			end
		end

		table.insert(sitesListFinal, 1, mainPartSites)
	else
		for _, localSite in ipairs(sitesFlatList) do
			local worldSite = partCFrame * localSite
			table.insert(sitesListFinal, worldSite)
		end
	end
	
	return sitesListFinal
end