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ball.go
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ball.go
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package main
import (
"math/rand"
"time"
rl "github.com/gen2brain/raylib-go/raylib"
)
const (
// The lower it is, the faster the ball will move.
BALL_SPEED = 8
)
// Custom type for ball launch direction.
type Direction uint8
const (
Random Direction = iota
Left
Right
)
type Ball struct {
color rl.Color
moving bool
rect rl.Rectangle
direction Direction
stop chan bool
}
var (
ball = Ball{
rect: rl.Rectangle{
Width: PADDLE_WIDTH,
Height: PADDLE_WIDTH,
},
}
)
func (b *Ball) launch() {
// Randomize Y position.
pos := rand.Intn(LIMIT_BOTTOM_Y-LIMIT_TOP_Y) + LIMIT_TOP_Y
// Reset ball and get ready to launch.
ball.color = veryDarkGray
b.rect.X = WINDOW_SIZE_X/2 - PADDLE_WIDTH/2
b.rect.Y = float32(pos)
// Launch the ball after one second.
b.moving = true
time.Sleep(time.Second)
ball.color = rl.LightGray
move()
}
func move() {
var (
deltaX = getDirection(ball.direction)
deltaY = getDirection(ball.direction)
)
ball.stop = make(chan bool, 1)
for {
select {
case <-ball.stop:
close(ball.stop)
ball.moving = false
return
default:
x := ball.rect.X + deltaX
y := ball.rect.Y + deltaY
if !xLimitOk(x) || leftPaddle.collidesWith(ball) || rightPaddle.collidesWith(ball) {
deltaX *= -1
}
ball.rect.X += deltaX
if !yLimitOk(y) {
deltaY *= -1
}
ball.rect.Y += deltaY
time.Sleep(BALL_SPEED * time.Millisecond)
}
}
}
func getDirection(d Direction) float32 {
switch d {
case Random:
d = Direction(rand.Intn(2) + 1)
case Left:
return -1
case Right:
return 1
}
return getDirection(d)
}