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vector: Add BezierCurveTo

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Updates #844
This commit is contained in:
Hajime Hoshi 2019-12-29 00:05:03 +09:00
parent bb39e94e8c
commit cee11bd822
2 changed files with 59 additions and 5 deletions
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44
examples/vector/main.go
View File

@ -17,10 +17,13 @@
package main
import (
"fmt"
"image/color"
"log"
"math"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
"github.com/hajimehoshi/ebiten/vector"
)
@ -95,7 +98,7 @@ func drawEbitenText(screen *ebiten.Image) {
path.LineTo(320, 55)
path.LineTo(290, 20)
path.Fill(screen, color.White)
path.Fill(screen, color.RGBA{0xdb, 0x56, 0x20, 0xff})
}
func drawEbitenLogo(screen *ebiten.Image, x, y int) {
@ -104,6 +107,7 @@ func drawEbitenLogo(screen *ebiten.Image, x, y int) {
var path vector.Path
xf, yf := float32(x), float32(y)
// TODO: Add curves
path.MoveTo(xf, yf+4*unit)
path.LineTo(xf, yf+6*unit)
path.LineTo(xf+2*unit, yf+6*unit)
@ -126,6 +130,38 @@ func drawEbitenLogo(screen *ebiten.Image, x, y int) {
path.Fill(screen, color.RGBA{0xdb, 0x56, 0x20, 0xff})
}
func maxCounter(index int) int {
return 128 + (17*index+32)%64
}
func drawWave(screen *ebiten.Image, counter int) {
var path vector.Path
const npoints = 8
indexToPoint := func(i int, counter int) (float32, float32) {
x, y := float32(i*screenWidth/(npoints-1)), float32(screenHeight/2)
y += float32(30 * math.Sin(float64(counter)*2*math.Pi/float64(maxCounter(i))))
return x, y
}
for i := 0; i <= npoints; i++ {
if i == 0 {
path.MoveTo(indexToPoint(i, counter))
continue
}
cpx0, cpy0 := indexToPoint(i-1, counter)
x, y := indexToPoint(i, counter)
cpx1, cpy1 := x, y
cpx0 += 30
cpx1 -= 30
path.BezierCurveTo(cpx0, cpy0, cpx1, cpy1, x, y)
}
path.LineTo(screenWidth, screenHeight)
path.LineTo(0, screenHeight)
path.Fill(screen, color.RGBA{0x33, 0x66, 0xff, 0xff})
}
var counter = 0
func update(screen *ebiten.Image) error {
@ -134,8 +170,12 @@ func update(screen *ebiten.Image) error {
return nil
}
screen.Fill(color.White)
drawEbitenText(screen)
drawEbitenLogo(screen, 20, 80)
drawEbitenLogo(screen, 20, 90)
drawWave(screen, counter)
ebitenutil.DebugPrint(screen, fmt.Sprintf("TPS: %0.2f", ebiten.CurrentTPS()))
return nil
}

20
vector/path.go
View File

@ -61,9 +61,23 @@ func (p *Path) QuadraticCurveTo(cpx, cpy, x, y float32) {
for num*num < dist {
num *= 2
}
for t := float32(0.0); t <= 1; t += 1.0 / 128.0 {
xf := t*t*x + 2*t*(1-t)*cpx + (1-t)*(1-t)*c.X
yf := t*t*y + 2*t*(1-t)*cpy + (1-t)*(1-t)*c.Y
for t := float32(0.0); t <= 1; t += 1.0 / float32(num) {
xf := (1-t)*(1-t)*c.X + 2*t*(1-t)*cpx + t*t*x
yf := (1-t)*(1-t)*c.Y + 2*t*(1-t)*cpy + t*t*y
p.LineTo(xf, yf)
}
}
func (p *Path) BezierCurveTo(cp0x, cp0y, cp1x, cp1y, x, y float32) {
c := p.cur
dist := float64((x-c.X)*(x-c.X) + (y-c.Y)*(y-c.Y))
num := 1.0
for num*num < dist {
num *= 2
}
for t := float32(0.0); t <= 1; t += 1.0 / float32(num) {
xf := (1-t)*(1-t)*(1-t)*c.X + 3*(1-t)*(1-t)*t*cp0x + 3*(1-t)*t*t*cp1x + t*t*t*x
yf := (1-t)*(1-t)*(1-t)*c.Y + 3*(1-t)*(1-t)*t*cp0y + 3*(1-t)*t*t*cp1y + t*t*t*y
p.LineTo(xf, yf)
}
}