Golang游戏图像旋转模拟运动（ebiten）

迈不过友情╰ 2022-11-15 06:23 210阅读 0赞

***运动效果***  
![在这里插入图片描述][20210331131402808.gif_pic_center]  
首先为Ebiten GeoM结构体(github.com\\hajimehoshi\\ebiten\\v2@v2.0.7\\geom.go)添加了一个可以旋转旋转中心的方法

//（x,y）为旋转中心坐标 
    // theta 为旋转角度，弧度制
    func (g *GeoM) RotateByPoint(x, y, theta float64) { 
    	if theta == 0 { 
    		return
    	}
    	sin, cos := math.Sincos(theta)
    	_tx, _ty := g.tx-x, g.ty-y
    
    	a := cos*(g.a_1+1) - sin*g.c
    	b := cos*g.b - sin*(g.d_1+1)
    	tx := cos*_tx - sin*_ty
    	c := sin*(g.a_1+1) + cos*g.c
    	d := sin*g.b + cos*(g.d_1+1)
    	ty := sin*_tx + cos*_ty
    
    	g.a_1 = a - 1
    	g.b = b
    	g.c = c
    	g.d_1 = d - 1
    	g.tx = tx + x
    	g.ty = ty + y
    }

创建Hamster结构体

package component
    
    import (
    	"github.com/hajimehoshi/ebiten/v2"
    	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
    	_ "image/png"
    	"math"
    	"time"
    )
    
    type Hamster struct { 
    	Image *ebiten.Image
    	Opts  *ebiten.DrawImageOptions
    	x     float64
    	y     float64
    	w     float64
    	h     float64
    }
    
    func NewHamster(x, y float64) *Hamster { 
    	image, _, err := ebitenutil.NewImageFromFile("example2/static/image/go.png")
    	if err != nil { 
    		panic(err)
    	}
    	opts := &ebiten.DrawImageOptions{ }
    	opts.GeoM.Translate(x, y)
    	w, h := image.Size()
    	return &Hamster{ 
    		Image: image,
    		Opts:  opts,
    		x:     x,
    		y:     y,
    		w:     float64(w),
    		h:     float64(h),
    	}
    }
    // Walk方法以下边线中点为旋转中心，循环左右旋转
    // 在main中开启协程执行
    func (h *Hamster) Walk() { 
    	for { 
    		x, y := h.x+h.w/2, h.y+h.h
    		h.Opts.GeoM.RotateByPoint(x, y, math.Pi/24)
    		time.Sleep(200 * time.Millisecond)
    		h.Opts.GeoM.RotateByPoint(x, y, -math.Pi/24)
    		time.Sleep(200 * time.Millisecond)
    		h.Opts.GeoM.RotateByPoint(x, y, -math.Pi/24)
    		time.Sleep(200 * time.Millisecond)
    		h.Opts.GeoM.RotateByPoint(x, y, math.Pi/24)
    		time.Sleep(200 * time.Millisecond)
    	}
    }

*`main.go`*

package main
    
    import (
    	"github.com/hajimehoshi/ebiten/v2"
    	"github.com/vua/vGame/example2/component"
    	"image/color"
    	"log"
    )
    
    type Game struct { 
    	bgc color.Color
    	w   int
    	h   int
    	hamster *component.Hamster
    }
    
    func (g *Game) Update() error { 
    	// Write your game's logical update.
    	return nil
    }
    
    func (g *Game) Draw(screen *ebiten.Image) { 
    	screen.Fill(g.bgc)
    	screen.DrawImage(g.hamster.Image, g.hamster.Opts)
    }
    
    func (g *Game) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) { 
    	return g.w, g.h
    }
    
    func (g *Game) walk(){ 
    	g.hamster.Walk()
    }
    
    func main() { 
    	game := &Game{ 
    		bgc: color.RGBA{ 0xff, 0xff, 0xff, 0xff},
    		w:   320,
    		h:   240,
    		hamster: component.NewHamster(149,120),
    	}
    	go game.walk()
    
    	ebiten.SetWindowSize(640, 480)
    	ebiten.SetWindowTitle("vGame")
    
    	if err := ebiten.RunGame(game); err != nil { 
    		log.Fatal(err)
    	}
    }

[20210331131402808.gif_pic_center]: https://img-blog.csdnimg.cn/20210331131402808.gif#pic_center