ebiten/example/paint/main.go
2015-01-07 04:27:57 +09:00

83 lines
2.0 KiB
Go

// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"fmt"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
"image/color"
"log"
"math"
)
const (
screenWidth = 320
screenHeight = 240
)
var (
count int
brushRenderTarget *ebiten.Image
canvasRenderTarget *ebiten.Image
)
func update(screen *ebiten.Image) error {
if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
count++
}
mx, my := ebiten.CursorPosition()
if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
op := &ebiten.DrawImageOptions{}
op.GeoM.Translate(float64(mx), float64(my))
op.ColorM.Scale(1.0, 0.25, 0.25, 1.0)
theta := 2.0 * math.Pi * float64(count%60) / 60.0
op.ColorM.Concat(ebiten.RotateHue(theta))
if err := canvasRenderTarget.DrawImage(brushRenderTarget, op); err != nil {
return err
}
}
if err := screen.DrawImage(canvasRenderTarget, nil); err != nil {
return err
}
if err := ebitenutil.DebugPrint(screen, fmt.Sprintf("(%d, %d)", mx, my)); err != nil {
return err
}
return nil
}
func main() {
var err error
brushRenderTarget, err = ebiten.NewImage(4, 4, ebiten.FilterNearest)
if err != nil {
log.Fatal(err)
}
brushRenderTarget.Fill(color.White)
canvasRenderTarget, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
if err != nil {
log.Fatal(err)
}
canvasRenderTarget.Fill(color.White)
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Paint (Ebiten Demo)"); err != nil {
log.Fatal(err)
}
}