134 lines
2.8 KiB
Go
134 lines
2.8 KiB
Go
package internal
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import (
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"image"
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"image/color"
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"math/rand"
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"time"
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"github.com/hajimehoshi/ebiten/v2"
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"github.com/hajimehoshi/ebiten/v2/vector"
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)
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type ball struct {
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x float32
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y float32
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initX float32
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initY float32
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speedX float32
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speedY float32
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r float32
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}
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const (
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ballBaseRadius = 5
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ballBaseSpeedX = 1.25
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ballBaseSpeedY = 1.25
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)
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func newBall(screenWidth, screenHeight int) *ball {
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fScreenWidth := float32(screenWidth)
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fScreenHeight := float32(screenHeight)
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r := ballBaseRadius * fScreenHeight / BaseHeight
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x := fScreenWidth/2.0 - r
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y := fScreenHeight/2.0 - r
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return &ball{
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x: x,
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y: y,
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initX: x,
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initY: y,
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speedX: randSpeedDirection() * ballBaseSpeedX * fScreenWidth / BaseWidth,
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speedY: randSpeedDirection() * ballBaseSpeedY * fScreenHeight / BaseHeight,
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r: r,
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}
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}
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var ballColor = color.White
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func (b *ball) draw(img *ebiten.Image) {
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vector.DrawFilledCircle(img, b.x, b.y, b.r, ballColor, false)
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}
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func (b *ball) update(bounds image.Rectangle, obstacles ...image.Rectangle) error {
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b.x, b.y, b.speedX, b.speedY = b.nextPosAndSpeed(bounds, obstacles...)
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return nil
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}
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//nolint:nonamedreturns
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func (b *ball) nextPos(bounds image.Rectangle, obstacles ...image.Rectangle) (x, y float32) {
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x, y, _, _ = b.nextPosAndSpeed(bounds, obstacles...)
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return x, y
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}
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//nolint:nonamedreturns
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func (b *ball) nextPosAndSpeed(bounds image.Rectangle, obstacles ...image.Rectangle) (x, y, speedX, speedY float32) {
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speedX, speedY = b.nextSpeed(bounds, obstacles...)
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return b.x + speedX, b.y + speedY, speedX, speedY
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}
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//nolint:nonamedreturns,gocyclo
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func (b *ball) nextSpeed(bounds image.Rectangle, obstacles ...image.Rectangle) (speedX, speedY float32) {
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ballBounds := b.bounds()
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speedX = b.speedX
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speedY = b.speedY
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if ballBounds.Max.X >= bounds.Max.X || ballBounds.Min.X <= bounds.Min.X {
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speedX *= -1
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}
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if ballBounds.Max.Y >= bounds.Max.Y || ballBounds.Min.Y <= bounds.Min.Y {
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speedY *= -1
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}
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for _, ob := range obstacles {
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inter := ob.Intersect(ballBounds)
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if inter == (image.Rectangle{}) {
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continue
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}
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if float32(ob.Min.X) >= b.x || float32(ob.Max.X) <= b.x {
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speedX *= -1
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}
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if float32(ob.Min.Y) >= b.y || float32(ob.Max.Y) <= b.y {
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speedY *= -1
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}
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}
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return speedX, speedY
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}
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func (b *ball) reset() {
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b.x = b.initX
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b.y = b.initY
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b.speedX *= randSpeedDirection()
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b.speedY *= randSpeedDirection()
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}
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func (b *ball) resize(x, y float32) {
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b.x *= x
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b.speedX *= x
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b.initX *= x
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b.y *= y
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b.speedY *= y
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b.initY *= y
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b.r *= y
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}
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func (b *ball) bounds() image.Rectangle {
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return image.Rect(int(b.x-b.r), int(b.y-b.r), int(b.x+b.r), int(b.y+b.r))
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}
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func randSpeedDirection() float32 {
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//nolint:gosec
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r := rand.New(rand.NewSource(time.Now().Unix()))
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if r.Intn(101) >= 50 {
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return -1
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}
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return 1
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}
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