// nextSpot picks where the sentinel will be going to by considering
// all the surrounding spaces and picking from the valid ones.
func (s *sentinel) nextSpot(plan grid.Grid) *gridSpot {
at := s.next
was := s.prev
w, h := plan.Size()
// using knowledge that the grid starts at 0, 0 and goes to size, -size.
// and that the outside border is also valid.
choices := []*gridSpot{}
if at.x >= -1 && at.y >= -1 && at.x <= w && at.y <= h {
if s.isValidSpot(plan, w, h, was, at.x+1, at.y) {
choices = append(choices, &gridSpot{at.x + 1, at.y})
}
if s.isValidSpot(plan, w, h, was, at.x-1, at.y) {
choices = append(choices, &gridSpot{at.x - 1, at.y})
}
if s.isValidSpot(plan, w, h, was, at.x, at.y+1) {
choices = append(choices, &gridSpot{at.x, at.y + 1})
}
if s.isValidSpot(plan, w, h, was, at.x, at.y-1) {
choices = append(choices, &gridSpot{at.x, at.y - 1})
}
}
if len(choices) > 0 {
way := 0
if len(choices) > 1 {
way = rand.Intn(len(choices))
}
return choices[way]
}
return was // backtrack should never happen.
}
// isValidSpot checks that a spot is valid for a sentinel, i.e. not a wall or the
// previous location.
func (s *sentinel) isValidSpot(plan grid.Grid, w, h int, old *gridSpot, x, y int) bool {
if x == old.x && y == old.y { // can't use previous position.
return false
}
if x >= 0 && y >= 0 && x < w && y < h { // exclude walls.
return plan.IsOpen(x, y)
}
if x >= -1 && y >= -1 && x <= w && y <= h { // outside edge ok.
return true
}
return false // anywhere else is a no-go zone.
}
// buildFloorPlan creates the level layout.
func (lvl *level) buildFloorPlan(root vu.Pov, hd *hud, plan grid.Grid) {
width, height := plan.Size()
for x := 0; x < width; x++ {
for y := 0; y < height; y++ {
xc := float64(x * lvl.units)
yc := float64(-y * lvl.units)
band := plan.Band(x, y) / 3
if x == width/2 && y == height/2 {
lvl.gcx, lvl.gcy = x, y // remember the maze center location
lvl.center = root.NewPov().SetLocation(xc, 0, yc)
m := lvl.center.NewModel("uvra").LoadMesh("tile").AddTex("drop1")
m.SetAlpha(0.7)
m.SetUniform("spin", 1.0)
m.SetUniform("fd", lvl.fade)
} else if plan.IsOpen(x, y) {
// the floor tiles.
tileLabel := lvl.tileLabel(band)
tile := root.NewPov().SetLocation(xc, 0, yc)
m := tile.NewModel("uva").LoadMesh("tile").AddTex(tileLabel)
m.SetAlpha(0.7)
m.SetUniform("fd", lvl.fade)
// remember the tile locations for drop spots inside the maze.
lvl.cc.addDropLocation(x, y)
} else {
// draw flat on the y plane with the maze extending into the screen.
wm := lvl.wallMeshLabel(band)
wt := lvl.wallTextureLabel(band)
wall := root.NewPov().SetLocation(xc, 0, yc)
m := wall.NewModel("uva").LoadMesh(wm).AddTex(wt)
m.SetUniform("fd", lvl.fade)
lvl.walls = append(lvl.walls, wall)
// add the wall to the minimap
hd.addWall(xc, yc)
}
}
}
// add core drop locations around the outside of the maze.
for x := -1; x < width+1; x++ {
lvl.cc.addDropLocation(x, -1)
lvl.cc.addDropLocation(x, height)
}
for y := 0; y < height; y++ {
lvl.cc.addDropLocation(-1, y)
lvl.cc.addDropLocation(width, y)
}
}