// Forest example (Diablo-style camera) for lance3d
// Fixed 3/4 camera, WASD movement
// Press ESC to exit.

var time_mod = use('time')
var lance3d = use('core')
var math = use('math/radians')

// Meshes
var ground_mesh = null
var trunk_mesh = null
var canopy_mesh = null
var player_mesh = null

// Materials
var ground_mat = null
var trunk_mat = null
var canopy_mat_a = null
var canopy_mat_b = null
var player_mat = null

// Player state
var player = {
  x: 0,
  y: 0.5,
  z: 0,
  yaw: 0,
  speed: 6.0
}

// Trees: array of {x, z, trunk_h, trunk_r, canopy_s, canopy_mat}
var trees = []
var num_trees = 80

var cam_offset = { x: 10, y: 12, z: 10 }

var last_time = 0

function _init() {
  log.console("lance3d Forest (Diablo camera) Example")
  log.console("WASD move, ESC exit")

  lance3d.set_style("ps1")

  lance3d.seed(1337)

  lance3d.set_lighting({
    sun_dir: [0.4, 1.0, 0.2],
    sun_color: [1.0, 0.95, 0.9],
    ambient: [0.35, 0.35, 0.40]
  })

  lance3d.set_fog({
    enabled: true,
    color: [0.55, 0.70, 0.90],
    near: 40,
    far: 160
  })

  // Create meshes
  ground_mesh = lance3d.make_plane(220, 220)
  trunk_mesh = lance3d.make_cube(1, 1, 1)
  canopy_mesh = lance3d.make_cube(1, 1, 1)
  player_mesh = lance3d.make_cube(1, 1, 1)

  // Create materials
  ground_mat = { paint: [0.12, 0.22, 0.10, 1.0], coverage: "opaque", face: "single", lamp: "lit" }
  trunk_mat = { paint: [0.35, 0.23, 0.14, 1.0], coverage: "opaque", face: "single", lamp: "lit" }
  canopy_mat_a = { paint: [0.11, 0.40, 0.18, 1.0], coverage: "opaque", face: "single", lamp: "lit" }
  canopy_mat_b = { paint: [0.09, 0.33, 0.14, 1.0], coverage: "opaque", face: "single", lamp: "lit" }
  player_mat = { paint: [0.85, 0.25, 0.20, 1.0], coverage: "opaque", face: "single", lamp: "lit" }

  // Generate trees
  var i = null
  var x = null
  var z = null
  for (i = 0; i < num_trees; i++) {
    x = (lance3d.rand() - 0.5) * 90
    z = (lance3d.rand() - 0.5) * 90

    trees.push({
      x: x,
      z: z,
      trunk_h: lance3d.rand() * 3 + 2,
      trunk_r: lance3d.rand() * 0.25 + 0.25,
      canopy_s: lance3d.rand() * 1.0 + 1.5,
      canopy_mat: lance3d.rand() < 0.5 ? canopy_mat_a : canopy_mat_b
    })
  }

  last_time = time_mod.number()
  frame()
}

function _update(dt) {
  if (lance3d.key('escape')) {
    $stop()
    return
  }

  // Movement input
  var forward = 0
  var right = 0
  var fx = null
  var fz = null
  var len = null
  if (lance3d.key('w')) forward += 1
  if (lance3d.key('s')) forward -= 1
  if (lance3d.key('d')) right -= 1
  if (lance3d.key('a')) right += 1

  if (forward != 0 || right != 0) {
    // Update yaw based on movement direction
    player.yaw = math.arc_tangent(forward, -right)

    fx = math.sine(player.yaw)
    fz = math.cosine(player.yaw)

    len = math.sqrt(fx * fx + fz * fz)
    if (len > 0) {
      fx /= len
      fz /= len
    }

    player.x += fx * player.speed * dt
    player.z += fz * player.speed * dt
  }
}

function _draw() {
  var i = null
  var tree = null
  var trunk_transform = null
  var canopy_transform = null
  var q = null
  var player_transform = null

  lance3d.clear(0.55, 0.70, 0.90, 1.0)

  // Set up camera following player
  lance3d.camera_perspective(55, 0.1, 300)
  lance3d.camera_look_at(
    {x: player.x + cam_offset.x, y: cam_offset.y, z: player.z + cam_offset.z},
    {x: player.x, y: 0, z: player.z}
  )

  // Draw ground
  lance3d.draw_mesh(ground_mesh, null, ground_mat)

  // Draw tree trunks
  for (i = 0; i < length(trees); i++) {
    tree = trees[i]
    trunk_transform = lance3d.trs_matrix(
      [tree.x, tree.trunk_h / 2, tree.z],
      [0, 0, 0, 1],
      [tree.trunk_r, tree.trunk_h, tree.trunk_r]
    )
    lance3d.draw_mesh(trunk_mesh, trunk_transform, trunk_mat)
  }

  // Draw tree canopies
  for (i = 0; i < length(trees); i++) {
    tree = trees[i]
    canopy_transform = lance3d.trs_matrix(
      [tree.x, tree.trunk_h + tree.canopy_s / 2, tree.z],
      [0, 0, 0, 1],
      [tree.canopy_s, tree.canopy_s, tree.canopy_s]
    )
    lance3d.draw_mesh(canopy_mesh, canopy_transform, tree.canopy_mat)
  }

  // Draw player
  q = lance3d.euler_to_quat(0, player.yaw, 0)
  player_transform = lance3d.trs_matrix(
    [player.x, player.y, player.z],
    [q.x, q.y, q.z, q.w],
    [0.7, 1.0, 0.7]
  )
  lance3d.draw_mesh(player_mesh, player_transform, player_mat)
}

function frame() {
  lance3d._begin_frame()
  
  if (!lance3d._process_events()) {
    log.console("Exiting...")
    $stop()
    return
  }
  
  var now = time_mod.number()
  var dt = now - last_time
  last_time = now
  
  _update(dt)
  _draw()
  
  lance3d._end_frame()
  
  $delay(frame, 1/60)
}

_init()