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
	Robot       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()
	log.Printf("player %s: sender close", p.Robot.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 msg Instruction
		err := websocket.JSON.Receive(p.ws, &msg)
		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
		}

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

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

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

			if msg.Probe != nil {
				p.Robot.Probe = msg.Probe
				p.Robot.ProbeResult = nil
			} else {
				p.Robot.Probe = nil
			}
		}

		if msg.Message != nil {
			p.Robot.Message = *msg.Message
		}

	}
	log.Printf("player %s: recv close", p.Robot.Id)
	p.ws.Close()
}

func (p *player) checkCollisions(g *game, move_vector v.Vector2d) (bool, v.Point2d, *player) {
	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, p.Robot.Position, move_vector)
	if collision {
		return collision, pos, nil
	}

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

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

	return collision, intersection_point, nil
}

func (p *player) Tick(g *game) {
	p.Robot.Collision = false
	p.Robot.Hit = false
	p.scan(g)

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

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

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

	new_heading := current_heading
	if p.Robot.MoveTo != nil {
		// Where do we WANT to be heading?
		new_heading = p.Robot.MoveTo.Sub(p.Robot.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(p.Robot.Stats.TurnSpeed) * delta) {
			// New heading should be a little less, take current heading and
			// rotate by the max turn radius per frame.
			rot := (float32(p.Robot.Stats.TurnSpeed) * delta) * v.Deg2rad

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

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

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

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

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

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

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

}

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

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

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

}

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

	p.Robot.LastFired = turn

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

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

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