mirror of
https://github.com/hajimehoshi/ebiten.git
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134 lines
3.5 KiB
Go
134 lines
3.5 KiB
Go
// Copyright 2022 The Ebitengine Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"fmt"
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"image"
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"image/color"
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"log"
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"math"
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"github.com/hajimehoshi/ebiten/v2"
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"github.com/hajimehoshi/ebiten/v2/ebitenutil"
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"github.com/hajimehoshi/ebiten/v2/inpututil"
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"github.com/hajimehoshi/ebiten/v2/vector"
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)
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const (
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screenWidth = 640
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screenHeight = 480
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)
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type Game struct {
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counter int
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aa bool
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showCenter bool
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}
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func (g *Game) Update() error {
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g.counter++
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if inpututil.IsKeyJustPressed(ebiten.KeyA) {
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g.aa = !g.aa
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}
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if inpututil.IsKeyJustPressed(ebiten.KeyC) {
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g.showCenter = !g.showCenter
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}
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return nil
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}
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func (g *Game) Draw(screen *ebiten.Image) {
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target := screen
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joins := []vector.LineJoin{
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vector.LineJoinMiter,
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vector.LineJoinMiter,
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vector.LineJoinBevel,
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vector.LineJoinRound,
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}
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caps := []vector.LineCap{
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vector.LineCapButt,
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vector.LineCapRound,
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vector.LineCapSquare,
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}
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ow, oh := target.Bounds().Dx(), target.Bounds().Dy()
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size := min(ow/(len(joins)+1), oh/(len(caps)+1))
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offsetX, offsetY := (ow-size*len(joins))/2, (oh-size*len(caps))/2
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// Render the lines on the target.
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for j, cap := range caps {
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for i, join := range joins {
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r := image.Rect(i*size+offsetX, j*size+offsetY, (i+1)*size+offsetX, (j+1)*size+offsetY)
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miterLimit := float32(5)
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if i == 1 {
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miterLimit = 10
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}
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g.drawLine(target, r, cap, join, miterLimit)
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}
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}
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msg := fmt.Sprintf(`FPS: %0.2f, TPS: %0.2f
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Press A to switch anti-aliasing.
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Press C to switch to draw the center lines.`, ebiten.ActualFPS(), ebiten.ActualTPS())
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ebitenutil.DebugPrint(screen, msg)
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}
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func (g *Game) drawLine(screen *ebiten.Image, region image.Rectangle, cap vector.LineCap, join vector.LineJoin, miterLimit float32) {
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c0x := float64(region.Min.X + region.Dx()/4)
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c0y := float64(region.Min.Y + region.Dy()/4)
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c1x := float64(region.Max.X - region.Dx()/4)
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c1y := float64(region.Max.Y - region.Dy()/4)
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r := float64(min(region.Dx(), region.Dy()) / 4)
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a0 := 2 * math.Pi * float64(g.counter) / (16 * ebiten.DefaultTPS)
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a1 := 2 * math.Pi * float64(g.counter) / (9 * ebiten.DefaultTPS)
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var path vector.Path
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sin0, cos0 := math.Sincos(a0)
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sin1, cos1 := math.Sincos(a1)
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path.MoveTo(float32(r*cos0+c0x), float32(r*sin0+c0y))
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path.LineTo(float32(-r*cos0+c0x), float32(-r*sin0+c0y))
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path.LineTo(float32(r*cos1+c1x), float32(r*sin1+c1y))
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path.LineTo(float32(-r*cos1+c1x), float32(-r*sin1+c1y))
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// Draw the main line in white.
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op := &vector.StrokeOptions{}
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op.LineCap = cap
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op.LineJoin = join
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op.MiterLimit = miterLimit
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op.Width = float32(r / 2)
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vector.StrokePath(screen, &path, color.White, g.aa, op)
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// Draw the center line in red.
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if g.showCenter {
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op.Width = 1
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vector.StrokePath(screen, &path, color.RGBA{0xff, 0, 0, 0xff}, g.aa, op)
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}
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}
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func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
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return screenWidth, screenHeight
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}
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func main() {
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var g Game
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ebiten.SetWindowSize(screenWidth, screenHeight)
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ebiten.SetWindowTitle("Lines (Ebitengine Demo)")
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if err := ebiten.RunGame(&g); err != nil {
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log.Fatal(err)
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}
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}
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