POC for taking a screenshot of a client's playermodel from a random angle from the server.

server_screenshot.lua

local TAG = "SCREENSHOT_SV"

if SERVER then
	util.AddNetworkString(TAG)
		
	local token_base = "1234567890_@#$abcdefghijklmnopqrstuvwxyz"
	local function generate_token()
		local ret = ""
		for _ = 1, math.random(10, 32) do
			local char = token_base[math.random(#token_base)]
			if math.random() > 0.5 then
				char = char:upper()
			end
			
			ret = math.random() > 0.5 and ret .. char or char .. ret
		end
		
		return ret
	end
	
	local token = generate_token()
	function SCREENSHOT(ply, pos)
		net.Start(TAG)
		net.WriteString(token)
		net.WriteVector(pos)
		net.Send(ply)
	end
	
	net.Receive(TAG, function(_, ply)
		local token = net.ReadString()
		local len = net.ReadInt(32)
		local compressed_data = net.ReadData(len)
		print(base64)
	end)
end

if CLIENT then
	local function rand_vec(lim, min, max)
		local x = math.random() > 0.5 and math.random(lim, max) or math.random(min, lim)
		local y = math.random() > 0.5 and math.random(lim, max) or math.random(min, lim)
		local z = math.random() > 0.5 and math.random(lim, max) or math.random(min, lim)
		
		return Vector(x, y, z)
	end
	
	local MAX_RETRIES = 20
	local function compute_rand_angle(ent, pos)
		local vec = rand_vec(100, 0, 500)
		local tr = util.TraceLine({
			start = pos, 
			endpos = pos + vec, 
		})
	
		local retries = 0
		while tr.Entity ~= ent do
			vec = rand_vec(100, 0, 500)
			tr = util.TraceLine({
				start = pos, 
				endpos = pos + vec, 
			})
		
			retries = retries + 1
			if retries >= MAX_RETRIES then break end
		end
		
		return pos + vec
	end
	
	net.Receive(TAG, function()
		local token = net.ReadString()
		local pos = net.ReadVector()
		
		local cam_pos = compute_rand_angle(LocalPlayer(), pos)
		hook.Add("CalcView", TAG, function(ply, _, _, fov)
			return {
				origin = cam_pos,
				angles = (pos - cam_pos):Angle(),
				fov = fov,
				drawviewer = true
			}
		end)
	
		timer.Simple(1, function()
			hook.Add("PostRender", TAG, function()
				local data = render.Capture({
					format = "png",
					x = 0,
					y = 0,
					w = ScrW(),
					h = ScrH(),
				})
			
				local compressed_data = util.Compress(util.Base64Encode(data))
				print(#compressed_data)
			
				net.Start(TAG)
				net.WriteString(token)
				net.WriteInt(#compressed_data, 32)
				net.WriteData(compressed_data, #compressed_data)
				net.SendToServer()
			
				hook.Remove("PostRender", TAG)
				hook.Remove("CalcView", TAG)
			end)
		end)
	end)
end