server/config.go

73 lines
2.1 KiB
Go

package server
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"log"
"os"
"strings"
)
// Config embodies the configuration for a game. These are populated in various
// ways (json POSTed to server, config file, constants) and are typically owned
// by a Controller.
type Config struct {
Tick int `json:"tick"` // ms
Timescale float64 `json:"timescale"`
Delta float64 `json:"delta"`
Width int `json:"width"`
Height int `json:"height"`
ObstacleCount int `json:"obstacle_count"`
Obstacles []Obstacle `json:'obstacles'`
MaxPoints int `json:"max_points"`
Mode string `json:"mode"`
}
const (
TICK = 60 // ms, this is how often physics is updated
TIMESCALE = 1.0 // this tweaks the temporal duration of a TICK
WIDTH = 800
HEIGHT = 550
OBSTACLE_COUNT = 5
MAX_POINTS = 500 // allowing for 50 pts in every category
DEFAULT_MODE = "deathmatch"
)
// LoadConfig takes the location of a json file that contains values desired to
// be used in the creation of games. Priority is given to values specified at
// game cration time using control channel, followed by values in config file,
// followed by constants defined above.
func LoadConfig(filename string) (Config, error) {
c := Config{
Tick: TICK,
Timescale: TIMESCALE,
Width: WIDTH,
Height: HEIGHT,
ObstacleCount: OBSTACLE_COUNT,
MaxPoints: MAX_POINTS,
Mode: DEFAULT_MODE,
}
home := os.Getenv("HOME")
if len(filename) > 1 && filename[:2] == "~/" {
filename = strings.Replace(filename, "~", home, 1)
}
if _, err := os.Stat(filename); os.IsNotExist(err) {
log.Printf("%+v not found, using defaults", filename)
} else {
log.Printf("found config file: %s", filename)
f, err := ioutil.ReadFile(filename)
if err != nil {
return c, err
}
err = json.Unmarshal(f, &c)
if err != nil {
return c, errors.New(fmt.Sprintf("config parse error: %s", err))
}
}
c.Delta = float64(c.Tick) / 1000.0 * c.Timescale
log.Printf("final config: %#v", c)
return c, nil
}