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examples/sprites: Rotate images (#277)

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This commit is contained in:
Hajime Hoshi 2017-05-28 04:09:04 +09:00
parent b66ead56c8
commit 3a58bd7f26
1 changed files with 11 additions and 0 deletions
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11
examples/sprites/main.go
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@ -20,6 +20,7 @@ import (
"fmt" "fmt"
_ "image/png" _ "image/png"
"log" "log"
"math"
"math/rand" "math/rand"
"github.com/hajimehoshi/ebiten" "github.com/hajimehoshi/ebiten"
@ -29,6 +30,7 @@ import (
const ( const (
screenWidth = 320 screenWidth = 320
screenHeight = 240 screenHeight = 240
maxAngle = 256
) )
var ( var (
@ -42,6 +44,7 @@ type Sprite struct {
y int y int
vx int vx int
vy int vy int
angle int
} }
func (s *Sprite) Update() { func (s *Sprite) Update() {
@ -61,6 +64,8 @@ func (s *Sprite) Update() {
s.y = 2*(screenHeight-s.imageHeight) - s.y s.y = 2*(screenHeight-s.imageHeight) - s.y
s.vy = -s.vy s.vy = -s.vy
} }
s.angle++
s.angle %= maxAngle
} }
type Sprites struct { type Sprites struct {
@ -102,9 +107,13 @@ func update(screen *ebiten.Image) error {
if ebiten.IsRunningSlowly() { if ebiten.IsRunningSlowly() {
return nil return nil
} }
w, h := ebitenImage.Size()
for i := 0; i < sprites.num; i++ { for i := 0; i < sprites.num; i++ {
s := sprites.sprites[i] s := sprites.sprites[i]
op.GeoM.Reset() op.GeoM.Reset()
op.GeoM.Translate(-float64(w)/2, -float64(h)/2)
op.GeoM.Rotate(2 * math.Pi * float64(s.angle) / maxAngle)
op.GeoM.Translate(float64(w)/2, float64(h)/2)
op.GeoM.Translate(float64(s.x), float64(s.y)) op.GeoM.Translate(float64(s.x), float64(s.y))
screen.DrawImage(ebitenImage, op) screen.DrawImage(ebitenImage, op)
} }
@ -132,6 +141,7 @@ func main() {
w, h := ebitenImage.Size() w, h := ebitenImage.Size()
x, y := rand.Intn(screenWidth-w), rand.Intn(screenHeight-h) x, y := rand.Intn(screenWidth-w), rand.Intn(screenHeight-h)
vx, vy := 2*rand.Intn(2)-1, 2*rand.Intn(2)-1 vx, vy := 2*rand.Intn(2)-1, 2*rand.Intn(2)-1
a := rand.Intn(maxAngle)
sprites.sprites[i] = &Sprite{ sprites.sprites[i] = &Sprite{
imageWidth: w, imageWidth: w,
imageHeight: h, imageHeight: h,
@ -139,6 +149,7 @@ func main() {
y: y, y: y,
vx: vx, vx: vx,
vy: vy, vy: vy,
angle: a,
} }
} }
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Sprites (Ebiten Demo)"); err != nil { if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Sprites (Ebiten Demo)"); err != nil {