server/player.go

package main

import (
	v "bitbucket.org/hackerbots/vector"
	"code.google.com/p/go.net/websocket"
	"log"
	"math"
	"math/rand"
)

type player struct {
	ws          *websocket.Conn
	Robots      []Robot
	send        chan *Boardstate
	Instruction Instruction
}

func (p *player) sender() {
	for things := range p.send {
		err := websocket.JSON.Send(p.ws, *things)
		if err != nil {
			break
		}
	}
	p.ws.Close()
	// TODO
	log.Printf("player %s: sender close", p.Robots[0].Id)
}

func (p *player) recv() {
	for {
		// XXX: need to mark myself as having received something, also binding
		// such action to a particular game turn ID
		var msgs PlayerInstructions
		err := websocket.JSON.Receive(p.ws, &msgs)
		if err != nil {
			// TODO: perhaps we could be a bit more precise in the handling of
			// this 'error' by selecting on some kill signal channel and this
			// json read?
			log.Print("problem receiving JSON from player: ", err)
			break
		}

		for _, r := range p.Robots {

			msg, ok := msgs.RobotInstructions[r.Id]
			if !ok {
				continue
			}

			if msg.Repair != nil && *msg.Repair == true {
				r.TargetSpeed = 0
				r.FireAt = nil
				r.MoveTo = nil
				if r.RepairCounter <= 0 {
					r.RepairCounter = 3.0
				}
			} else if msg.Scan != nil && *msg.Scan == true {
				r.TargetSpeed = 0
				r.FireAt = nil
				r.MoveTo = nil
				r.ActiveScan = true
			} else {
				r.RepairCounter = 0
				r.ActiveScan = false

				// Reapiring halts all other activity
				if msg.MoveTo != nil {
					r.MoveTo = msg.MoveTo
				}
				if msg.FireAt != nil {
					r.FireAt = msg.FireAt
				}

				if msg.TargetSpeed != nil {
					r.TargetSpeed = float32(*msg.TargetSpeed)
				} else {
					r.TargetSpeed = r.Stats.Speed
				}

				if msg.Probe != nil {
					r.Probe = msg.Probe
					r.ProbeResult = nil
				} else {
					r.Probe = nil
				}
			}

			if msg.Message != nil {
				r.Message = *msg.Message
			}
		}
	}

	log.Printf("player %s: recv close", p.Robots[0].Id)
	p.ws.Close()
}

func (r *Robot) checkCollisions(g *game, move_vector v.Vector2d) (bool, v.Point2d, *Robot) {
	collision := false
	intersection_point := v.Point2d{X: 0, Y: 0}

	// Check Walls
	r_walls := v.Rect2d{A: v.Point2d{X: 0, Y: 0}, B: v.Point2d{X: g.width, Y: g.height}}
	collision, _, pos := v.RectIntersection(r_walls, r.Position, move_vector)
	if collision {
		return collision, pos, nil
	}

	// Check Other Bots
	for player := range g.players {
		for _, bot := range player.Robots {
			if bot.Id == r.Id {
				continue
			}
			player_rect := v.RectFromPoint(bot.Position, 3)
			collision, _, pos := v.RectIntersection(player_rect, r.Position, move_vector)
			if collision {
				return collision, pos, &bot
			}
		}
	}

	// Check Obstacles
	for _, obj := range g.obstacles {
		collision, _, pos := v.RectIntersection(obj.Bounds, r.Position, move_vector)
		if collision {
			return collision, pos, nil
		}
	}

	return collision, intersection_point, nil
}

func (p *player) Tick(g *game) {
	for _, r := range p.Robots {

		r.Collision = false
		r.Hit = false
		r.scan(g)

		// Adjust Speed
		if r.Speed < r.TargetSpeed {
			r.Speed += (r.Stats.Acceleration * delta)
			if r.Speed > r.TargetSpeed {
				r.Speed = r.TargetSpeed
			}

		} else if float32(math.Abs(float64(r.Speed-r.TargetSpeed))) > v.Epsilon {
			r.Speed -= (r.Stats.Acceleration * delta)
		} else {
			r.Speed = r.TargetSpeed
		}

		// Adjust Heading
		current_heading := r.Heading
		if current_heading.Mag() == 0 && r.MoveTo != nil {
			// We may have been stopped before this and had no heading
			current_heading = r.MoveTo.Sub(r.Position).Normalize()
		}

		new_heading := current_heading
		if r.MoveTo != nil {
			// Where do we WANT to be heading?
			new_heading = r.MoveTo.Sub(r.Position).Normalize()
		}

		if new_heading.Mag() > 0 {
			// Is our direction change too much? Hard coding to 5 degrees/s for now
			angle := v.Angle(current_heading, new_heading) * v.Rad2deg

			dir := 1.0
			if angle < 0 {
				dir = -1.0
			}

			// Max turn radius in this case is in degrees per second
			if float32(math.Abs(float64(angle))) > (float32(r.Stats.TurnSpeed) * delta) {
				// New heading should be a little less, take current heading and
				// rotate by the max turn radius per frame.
				rot := (float32(r.Stats.TurnSpeed) * delta) * v.Deg2rad

				new_heading = current_heading.Rotate(rot * float32(dir))
			}

			move_vector := new_heading.Scale(r.Speed * delta)
			collision, intersection_point, hit_robot := r.checkCollisions(g, move_vector)
			if collision {
				r.Collision = true
				if hit_robot != nil {
					hit_robot.Health -= int(r.Speed / 10.0)
					hit_robot.Speed = (hit_robot.Speed * 0.1)
					hit_robot.Heading = r.Heading
				}
				move_by := intersection_point.Sub(r.Position)
				move_dist := move_by.Scale(float32(math.Floor(float64(move_by.Mag()-3.0))) / move_by.Mag())

				r.Position = r.Position.Add(move_dist)
				r.Health -= int(r.Speed / 10.0)
				r.MoveTo = &r.Position
				r.Speed = (r.Speed * 0.1)
				r.Heading = r.Heading.Scale(-1.0)
			} else {
				r.Position = r.Position.Add(move_vector)
				if new_heading.Mag() > 0 {
					r.Heading = new_heading
				} else {
					log.Printf("Zero Heading %v", new_heading)
				}
			}
		}

		// We only self repair when we're stopped
		if math.Abs(float64(r.Speed)) < v.Epsilon && r.RepairCounter > 0 {
			r.RepairCounter -= delta
			if r.RepairCounter < 0 {
				r.Health += g.repair_hp
				r.RepairCounter = g.repair_rate
			}
		}

		// We only self repair when we're stopped
		if math.Abs(float64(r.Speed)) < v.Epsilon && r.ActiveScan {
			r.ScanCounter += delta * float32(r.Stats.ScannerRadius) * 0.1
		} else if r.ScanCounter > 0 {
			r.ScanCounter -= delta * float32(r.Stats.ScannerRadius) * 0.05
			if r.ScanCounter <= 0 {
				r.ScanCounter = 0
			}
		}

		if r.FireAt != nil {
			proj := r.fire(g.projectiles, g.turn)
			if proj != nil {
				g.projectiles[proj] = true
			}
		}

		if r.Probe != nil && r.ProbeResult == nil {
			probe_vector := r.Probe.Sub(r.Position)
			coll, pos, _ := r.checkCollisions(g, probe_vector)
			if coll {
				r.ProbeResult = &pos
			}
		}
	}
}

func (r *Robot) scan(g *game) {
	r.Scanners = r.Scanners[:0]
	for player, _ := range g.players {
		for _, bot := range player.Robots {
			if bot.Id == r.Id || bot.Health <= 0 {
				continue
			}
			dist := v.Distance(bot.Position, r.Position)
			if dist < float32(r.Stats.ScannerRadius+int(r.ScanCounter)) {
				s := Scanner{
					Id:   bot.Id,
					Type: "robot",
				}
				r.Scanners = append(r.Scanners, s)
			}
		}
	}

	for proj, _ := range g.projectiles {
		if proj.Owner == r {
			continue
		}

		dist := v.Distance(proj.Position, r.Position)
		if dist < float32(r.Stats.ScannerRadius+int(r.ScanCounter)) {
			s := Scanner{
				Id:   proj.Id,
				Type: "projectile",
			}
			r.Scanners = append(r.Scanners, s)
		}
	}

}

func (r *Robot) fire(projectiles map[*Projectile]bool, turn int) *Projectile {
	// Throttle the fire rate
	time_since_fired := (float32(turn) * (delta * 1000)) - (float32(r.LastFired) * (delta * 1000))
	if time_since_fired < float32(r.Stats.FireRate) {
		return nil
	}

	r.LastFired = turn

	return &Projectile{
		Id:       idg.Hash(),
		Position: r.Position,
		MoveTo:   *r.FireAt,
		Damage:   r.Stats.WeaponDamage,
		Radius:   r.Stats.WeaponRadius,
		Speed:    r.Stats.WeaponSpeed,
		Owner:    r,
	}
}

func (r *Robot) reset(g *game) {
	for {
		start_pos := v.Point2d{
			X: rand.Float32() * float32(g.width),
			Y: rand.Float32() * float32(g.height),
		}
		r.MoveTo = &start_pos
		r.Position = start_pos
		r.Health = r.Stats.Hp

		// Check Obstacles
		retry := false
		for _, obj := range g.obstacles {
			_, inside, _ := v.RectIntersection(obj.Bounds, r.Position, v.Vector2d{0, 0})
			if inside {
				retry = true
			}
		}
		if !retry {
			break
		}
	}
}