package main import ( "image/color" _ "image/png" "log" "math" "github.com/hajimehoshi/ebiten/v2" "github.com/hajimehoshi/ebiten/v2/ebitenutil" "github.com/hajimehoshi/ebiten/v2/vector" ) var red = color.RGBA{0xcc, 0x66, 0x66, 0xff} var green = color.RGBA{0xb5, 0xbd, 0x68, 0xff} const screen_w, screen_h = 640, 480 const gravity, friction, air_resistance = 0.9, 0.01, 0.01 type Penguin struct { img *ebiten.Image x, y float64 xv, yv float64 onGround bool fx []float64 fy []float64 } func newPenguin() Penguin { penguin := Penguin{ x: screen_w / 2, y: 0, xv: 0, yv: 0, } var err error penguin.img, _, err = ebitenutil.NewImageFromFile("assets/penguin.png") if err != nil { log.Fatal(err) } return penguin; } func (p *Penguin) Width() (float64) { return float64(p.img.Bounds().Dx()) } func (p *Penguin) Height() (float64) { return float64(p.img.Bounds().Dy()) } func (p *Penguin) Cx() (float64) { return p.x + float64(p.img.Bounds().Dx()) / 2 } func (p *Penguin) Cy() (float64) { return p.y + float64(p.img.Bounds().Dy()) / 2 } func (penguin *Penguin) draw(screen *ebiten.Image, game Game) { op := &ebiten.DrawImageOptions{} if penguin.onGround { angle := game.ground.angle(penguin.Cx(), 2) tx, ty := float64(penguin.Width()) / 2, float64(penguin.Height()) op.GeoM.Translate(-tx, -ty) op.GeoM.Rotate(angle) op.GeoM.Translate(tx, ty) } op.GeoM.Translate(penguin.x, penguin.y) screen.DrawImage(penguin.img, op) } func (penguin *Penguin) drawBounds(screen *ebiten.Image, game Game) { const s float64 = 200 tx, ty := 0.0, 0.0 for i := range penguin.fx{ x, y := penguin.fx[i], penguin.fy[i] tx += x ty += y vector.StrokeLine(screen, float32(penguin.Cx()), float32(penguin.y+penguin.Height()), float32(penguin.Cx() + x*s), float32(penguin.y + penguin.Height() + y*s), 4, green, true) } vector.StrokeLine(screen, float32(penguin.Cx()), float32(penguin.y+penguin.Height()), float32(penguin.Cx() + tx*s), float32(penguin.y + penguin.Height() + ty*s), 4, red, true) } func (penguin *Penguin) update(game *Game) { gx, gy := 0.0, gravity penguin.fx = []float64{gx} penguin.fy = []float64{gy} if penguin.onGround{ angle := game.ground.angle(penguin.Cx(), 1) dx, dy := Normalize(game.ground.normal(penguin.Cx(), 1)) nx, ny := Multiply(dx, dy, gravity * math.Cos(angle)) sd := 0.0 if penguin.xv > 0 { sd = 1 } else if penguin.xv < 0 { sd = -1 } rx, ry := Multiply(-sd*dy, sd*dx, -friction) penguin.fx = append(penguin.fx, nx, rx) penguin.fy = append(penguin.fy, ny, ry) } ax, ay := Multiply(penguin.xv, penguin.yv, -air_resistance) penguin.fx = append(penguin.fx, ax) penguin.fy = append(penguin.fy, ay) for _, v := range penguin.fx{ penguin.xv += v } for _, v := range penguin.fy{ penguin.yv += v } penguin.x += penguin.xv penguin.y += penguin.yv if penguin.y+penguin.Height() > game.ground(penguin.Cx()){ penguin.y = game.ground(penguin.Cx()) - penguin.Height() penguin.onGround = true } else { penguin.onGround = false } } func (p *Penguin) collideWithCurve(curve Curve, xv, yv float64) bool { cy1 := curve(p.Cx() + xv) y1 := p.y + yv y2 := yv + p.y + p.Height() if y1 < cy1 && cy1 < y2 { return true } return false } func (g *Game) init() { g.penguin = newPenguin() } type Curve func(x float64)(y float64) func (curve Curve) draw(dst *ebiten.Image, clr color.Color, width float32, resolution int, antialias bool) { for x1 := 0; x1 < screen_w; x1 += resolution { x2 := x1 + resolution y1 := curve(float64(x1)) y2 := curve(float64(x2)) vector.StrokeLine(dst, float32(x1), float32(y1), float32(x2), float32(y2), width, color.RGBA{0x19, 0x19, 0x19, 0xff}, true) } } func (curve Curve) delta(x, r float64) (float64, float64){ x1, x2 := x + r, x - r y1, y2 := curve(x1), curve(x2) dx, dy := x2 - x1, y2 - y1 return dx, dy } func (curve Curve) angle(x, r float64) (float64){ dx, dy := curve.delta(x, r) return math.Atan(dy / dx) } func (curve Curve) normal(x, r float64) (float64, float64){ dx, dy := curve.delta(x, r) //m := -(dx / dy) return -dy,dx } func Normalize(x, y float64) (float64, float64) { m := math.Sqrt(x*x + y*y) return x/m, y/m } func Angle(x, y float64) (float64) { return math.Atan(y / x) } func Multiply(x, y, c float64) (float64, float64) { return x*c, y*c } func Magnitude(x, y float64) (float64) { return math.Sqrt(x*x + y*y) } type Game struct{ penguin Penguin ground Curve } func (g *Game) Update() error { if ebiten.IsMouseButtonPressed(ebiten.MouseButton0){ cx, cy := ebiten.CursorPosition() g.penguin.x = float64(cx) - g.penguin.Width()/2 g.penguin.y = float64(cy) - g.penguin.Height()/2 g.penguin.xv = 0 g.penguin.yv = 0 } if g.penguin.onGround{ if ebiten.IsKeyPressed(ebiten.KeyA) { g.penguin.xv -= 0.1 } if ebiten.IsKeyPressed(ebiten.KeyD) { g.penguin.xv += 0.1 } if ebiten.IsKeyPressed(ebiten.KeySpace) { g.penguin.onGround = false fx, fy := Normalize(g.ground.normal(g.penguin.Cx(), 2)) const jumpHeight = 8 var ex, ey float64 = 0, -1 switch { case ebiten.IsKeyPressed(ebiten.KeyA): ex -= 1 case ebiten.IsKeyPressed(ebiten.KeyD): ex += 1 case ebiten.IsKeyPressed(ebiten.KeyS): ey += 1 } g.penguin.xv += (ex + fx) * jumpHeight g.penguin.yv += (ey + fy) * jumpHeight } } g.penguin.update(g) return nil } func (g *Game) Draw(screen *ebiten.Image) { screen.Fill(color.RGBA{0xfe, 0xfe, 0xfe, 0xff}) g.ground.draw(screen, color.RGBA{0x19, 0x19, 0x19, 0xff}, 4, 16, true); g.penguin.draw(screen, *g) g.penguin.drawBounds(screen, *g) } func (g *Game) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) { return 640, 480 } func main() { ebiten.SetWindowSize(640, 480) ebiten.SetWindowTitle("penguin") //ebiten.SetTPS(10) game := Game{} game.ground = func(x float64)(y float64) { //return 200-math.Pow((x - 320)/320, 3)+math.Pow((x-320), 2)/300 //return 400-math.Pow((x-320)/20, 2) //return 400 return 240+50*math.Cos(x/30) } game.init() if err := ebiten.RunGame(&game); err != nil { log.Fatal(err) } }