render: add cross-platform desktop companion display

tests/engine/desktop_companion.lua

@@ -0,0 +1,56 @@
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+local clock, quit = 1, false
+local sent, queue, draws = {}, {}, 0
+local peer = {
+  send = function(_, data) sent[#sent + 1] = data end,
+  disconnect_now = function() end,
+}
+local host = {
+  connect = function() return peer end,
+  service = function()
+    if #queue == 0 then return nil end
+    return table.remove(queue, 1)
+  end,
+}
+local rendered = {
+  setFilter = function() end, replacePixels = function() end,
+  release = function() end,
+}
+love = {
+  timer = { getTime = function() return clock end },
+  data = { decompress = function(_, _, value) return value end },
+  image = { newImageData = function(w, h, format, raw)
+    assert(w == 1 and h == 1 and format == "rgba8" and raw == "rgba")
+    return {}
+  end },
+  graphics = {
+    newImage = function() return rendered end,
+    getDimensions = function() return 100, 100 end,
+    clear = function() end, setColor = function() end,
+    draw = function() draws = draws + 1 end,
+  },
+  event = { quit = function() quit = true end },
+}
+package.preload.enet = function()
+  return { host_create = function() return host end }
+end
+
+require("src.render.DesktopCompanion").install({ port = 50000, token = "token" })
+queue[#queue + 1] = { type = "connect" }
+love.update()
+assert(sent[#sent] == "Htoken", "companion authenticates after connecting")
+queue[#queue + 1] = {
+  type = "receive", data = "Ftoken\n1,1,0,auto\nrgba",
+}
+love.update()
+love.draw()
+assert(draws == 1, "companion draws a received frame")
+love.mousepressed(50, 50, 1)
+love.mousereleased(50, 50, 1)
+assert(sent[#sent - 1] == "Itoken\ndown,0,0"
+  and sent[#sent] == "Itoken\nup,0,0", "mouse input maps back to source pixels")
+queue[#queue + 1] = { type = "receive", data = "Qtoken" }
+love.update()
+assert(quit, "parent can close the companion")
+print("desktop companion: ok")

tests/engine/desktop_second_screen.lua

@@ -0,0 +1,57 @@
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+local clock = 1
+love = {
+  timer = { getTime = function() return clock end },
+  data = {
+    hash = function() return "digest" end,
+    encode = function() return "0123456789abcdef0123456789abcdef" end,
+    compress = function(_, _, value) return value end,
+  },
+}
+
+local sent, spawned, queue = {}, nil, {}
+local peer = {
+  send = function(_, data, channel, flag)
+    sent[#sent + 1] = { data = data, channel = channel, flag = flag }
+  end,
+  disconnect_now = function() end,
+}
+local host = {
+  service = function()
+    if #queue == 0 then return nil end
+    return table.remove(queue, 1)
+  end,
+  destroy = function() end,
+}
+
+package.loaded["src.core.Platform"] = { canSpawnProcess = function() return true end }
+package.loaded["src.core.HostShell"] = {
+  spawnSelfDetached = function(args) spawned = args return true end,
+}
+package.preload.enet = function()
+  return { host_create = function() return host end }
+end
+
+local Screen = require("src.render.SecondScreen")
+assert(Screen.usable(), "the shared facade selects the desktop backend")
+Screen.setEnabled(true)
+assert(spawned and spawned[1]:match("^%-%-display%-companion=%d+,[%w]+$"),
+  "enabling launches one companion of this app")
+local token = spawned[1]:match(",([%w]+)$")
+queue[#queue + 1] = { type = "receive", peer = peer, data = "H" .. token }
+assert(Screen.detected(), "a token-authenticated companion becomes detected")
+
+local pixels = { getString = function() return "rgba" end }
+assert(Screen.push(pixels, 1, 1, 0x102030, "auto"),
+  "a connected companion accepts a frame")
+assert(sent[#sent].data:find("^F" .. token .. "\n1,1,1056816,auto\nrgba"),
+  "frame metadata and pixels stay in one loopback packet")
+
+queue[#queue + 1] = {
+  type = "receive", peer = peer, data = "I" .. token .. "\ndown,3,4",
+}
+assert(Screen.pollTouch() == "down,3,4", "companion input returns to the mod")
+Screen.setEnabled(false)
+assert(sent[#sent].data == "Q" .. token, "disabling closes the companion")
+print("desktop second screen: ok")

tests/engine/hostshell_spawn_self.lua

@@ -0,0 +1,32 @@
+package.path = "./?.lua;./?/init.lua;" .. package.path
+
+local osName, fused, command = "Windows", true, nil
+love = {
+  system = { getOS = function() return osName end },
+  filesystem = {
+    getExecutablePath = function() return "C:\\Game\\gen1recomp.exe" end,
+    getSource = function() return "C:\\Source\\gen1recomp" end,
+    isFused = function() return fused end,
+  },
+}
+package.loaded["src.core.Platform"] = { canSpawnProcess = function() return true end }
+local execute = os.execute
+os.execute = function(value) command = value return 0 end
+
+local HostShell = require("src.core.HostShell")
+assert(HostShell.spawnSelfDetached({ "--display-companion=50000,token" }))
+assert(command:find('start "" /b ', 1, true)
+  and command:find('"C:\\Game\\gen1recomp.exe"', 1, true),
+  "Windows launches the fused app detached")
+
+osName, fused = "Linux", false
+assert(HostShell.spawnSelfDetached({ "--display-companion=50000,token" }))
+assert(command:find("'C:\\Source\\gen1recomp'", 1, true)
+  and command:sub(-1) == "&", "Linux source runs include the game folder")
+
+osName, fused = "OS X", true
+assert(HostShell.spawnSelfDetached({ "--display-companion=50000,token" }))
+assert(not command:find("start", 1, true) and command:sub(-1) == "&",
+  "macOS uses the same detached POSIX path")
+os.execute = execute
+print("spawn self detached: ok")