-- Navigation:  a walkable mesh baked from Sponza's floor, a path traced along the nave round the
-- columns (drawn as a chain of thin posts), and six Foxes wandering between random points on the
-- mesh without walking through the columns or each other (onNavArrived sends each to a new spot).
local font   = fontLoad("Singe/FreeSansBold.ttf", 28)
local frames = 0

fontSelect(font)
sceneEnable(true)
sceneSetBackground(120, 150, 200, 255)
sceneSetAmbient(120, 126, 150)
sceneSetShadowSize(2048)

local model  = modelLoad("testScripts/Models/Sponza.glb")
local sponza = modelInstance(model)

local sun = lightNew(LIGHT_DIRECTIONAL)
nodeSetPosition(sun, 5, 22, 4)
nodeLookAt(sun, -2, 0, -1.5)
lightSetIntensity(sun, 4.5)
lightSetColor(sun, 255, 236, 205)
lightSetShadow(sun, true)

-- The mesh:  an agent 0.4 wide and 1.6 tall that climbs 0.3 and walks slopes to 45 degrees.
local nav = navNew(0.4, 1.6, 45, 0.3)
navAddNode(nav, sponza)
navBuild(nav)

-- The path from one end of the nave to the other, as posts at its corners and along its legs.
local marker = materialNew()
materialSetColor(marker, 255, 60, 40)
materialSetEmissive(marker, 120, 20, 10)
local path = navPath(nav, 11, 0.2, 0, -11, 0.2, 0)
local pathPosts = 0
if path then
	for i = 1, #path do
		local post = nodeNew()
		nodeSetMesh(post, meshCylinder(0.08, 0.6, 8), marker)
		nodeSetPosition(post, path[i][1], path[i][2] + 0.3, path[i][3])
		pathPosts = pathPosts + 1
		if i < #path then
			local dx, dy, dz = path[i + 1][1] - path[i][1], path[i + 1][2] - path[i][2], path[i + 1][3] - path[i][3]
			local length = math.sqrt(dx * dx + dy * dy + dz * dz)
			for s = 1, math.floor(length / 0.8) do
				local t = s * 0.8 / length
				local p = nodeNew()
				nodeSetMesh(p, meshSphere(0.06, 8), marker)
				nodeSetPosition(p, path[i][1] + dx * t, path[i][2] + dy * t + 0.1, path[i][3] + dz * t)
			end
		end
	end
end

-- The Foxes, each an agent sent to a random point and, when it arrives, to another.
local foxModel = modelLoad("testScripts/Models/Fox.glb")
local agents   = {}
local foxes    = {}
for i = 1, 6 do
	local fox = modelInstance(foxModel)
	nodeSetScale(fox, 0.01)
	local x, y, z = navRandomPoint(nav)
	nodeSetPosition(fox, x, y, z)
	animationPlay(fox, "Walk", true)
	local agent = navAgentNew(nav, fox, 0.35, 1.0, 1.4)
	local tx, ty, tz = navRandomPoint(nav)
	navAgentMoveTo(agent, tx, ty, tz)
	agents[agent] = fox
	foxes[i] = fox
end

function onNavArrived(agent)
	local x, y, z = navRandomPoint(nav)
	navAgentMoveTo(agent, x, y, z)
end

local camera = nodeNew()
cameraSet(camera)
cameraSetPerspective(60, 0.05, 100)

local stops = {
	{ 10, 3, 0,     -10, 0.5, 0 },     -- Down the nave along the path
	{ 0, 5.5, 1,    0, 0.3, -6 },      -- From the gallery height over the atrium, the Foxes about
	{ 4, 1.2, 0.5,  -6, 0.6, 0.5 },    -- Low along the nave among them
	{ -9, 1.6, 0.3, 8, 0.4, 0 },       -- From the far end back along the path
}

function onOverlayUpdate()
	local stop = stops[math.min(#stops, math.floor(frames / 45) + 1)]
	frames = frames + 1
	nodeSetPosition(camera, stop[1], stop[2], stop[3])
	nodeLookAt(camera, stop[4], stop[5], stop[6])
	overlayClear()
	fontPrint(20, 20, string.format("Navigation, frame %d  path corners %d", frames, pathPosts))
	if frames == 40 or frames == 85 or frames == 130 or frames == 175 then
		singeScreenshot()
		for agent, fox in pairs(agents) do
			local x, y, z = nodeGetWorldPosition(fox)
			local vx, vy, vz = navAgentGetVelocity(agent)
			debugPrint(string.format("frame %d agent %d at %.1f %.1f %.1f moving %.2f %.2f", frames, agent, x, y, z, vx, vz))
		end
	end
	if frames == 180 then
		singeQuit()
	end
end