mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-14 15:07:26 +01:00
144 lines
3.3 KiB
Go
144 lines
3.3 KiB
Go
// Copyright 2016 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.
|
|
|
|
// +build example
|
|
|
|
package main
|
|
|
|
import (
|
|
"image"
|
|
"image/color"
|
|
_ "image/jpeg"
|
|
"log"
|
|
"math"
|
|
|
|
"github.com/hajimehoshi/ebiten"
|
|
"github.com/hajimehoshi/ebiten/ebitenutil"
|
|
)
|
|
|
|
const (
|
|
screenWidth = 320
|
|
screenHeight = 240
|
|
)
|
|
|
|
var (
|
|
gophersImage *ebiten.Image
|
|
fiveyearsImage *ebiten.Image
|
|
maskImage *ebiten.Image
|
|
spotLightImage *ebiten.Image
|
|
spotLightX = 0
|
|
spotLightY = 0
|
|
spotLightVX = 1
|
|
spotLightVY = 1
|
|
)
|
|
|
|
func update(screen *ebiten.Image) error {
|
|
spotLightX += spotLightVX
|
|
spotLightY += spotLightVY
|
|
if spotLightX < 0 {
|
|
spotLightX = -spotLightX
|
|
spotLightVX = -spotLightVX
|
|
}
|
|
if spotLightY < 0 {
|
|
spotLightY = -spotLightY
|
|
spotLightVY = -spotLightVY
|
|
}
|
|
w, h := spotLightImage.Size()
|
|
maxX, maxY := screenWidth-w, screenHeight-h
|
|
if maxX < spotLightX {
|
|
spotLightX = -spotLightX + 2*maxX
|
|
spotLightVX = -spotLightVX
|
|
}
|
|
if maxY < spotLightY {
|
|
spotLightY = -spotLightY + 2*maxY
|
|
spotLightVY = -spotLightVY
|
|
}
|
|
|
|
if err := maskImage.Clear(); err != nil {
|
|
return err
|
|
}
|
|
|
|
op := &ebiten.DrawImageOptions{}
|
|
op.GeoM.Translate(float64(spotLightX), float64(spotLightY))
|
|
if err := maskImage.DrawImage(spotLightImage, op); err != nil {
|
|
return err
|
|
}
|
|
|
|
op = &ebiten.DrawImageOptions{}
|
|
op.CompositeMode = ebiten.CompositeModeSourceOut
|
|
if err := maskImage.DrawImage(fiveyearsImage, op); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := screen.Fill(color.RGBA{0x00, 0x00, 0x80, 0xff}); err != nil {
|
|
return err
|
|
}
|
|
if err := screen.DrawImage(gophersImage, &ebiten.DrawImageOptions{}); err != nil {
|
|
return err
|
|
}
|
|
if err := screen.DrawImage(maskImage, &ebiten.DrawImageOptions{}); err != nil {
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func max(a, b int) int {
|
|
if a < b {
|
|
return b
|
|
}
|
|
return a
|
|
}
|
|
|
|
func min(a, b int) int {
|
|
if a < b {
|
|
return a
|
|
}
|
|
return b
|
|
}
|
|
|
|
func main() {
|
|
var err error
|
|
gophersImage, _, err = ebitenutil.NewImageFromFile("_resources/images/gophers.jpg", ebiten.FilterNearest)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
fiveyearsImage, _, err = ebitenutil.NewImageFromFile("_resources/images/fiveyears.jpg", ebiten.FilterNearest)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
maskImage, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
|
|
as := image.Point{128, 128}
|
|
a := image.NewAlpha(image.Rectangle{image.ZP, as})
|
|
for j := 0; j < as.Y; j++ {
|
|
for i := 0; i < as.X; i++ {
|
|
r := as.X / 2
|
|
d := math.Sqrt(float64((i-r)*(i-r) + (j-r)*(j-r)))
|
|
b := uint8(max(0, min(0xff, 3*0xff-int(d*3*0xff)/r)))
|
|
a.SetAlpha(i, j, color.Alpha{b})
|
|
}
|
|
}
|
|
spotLightImage, err = ebiten.NewImageFromImage(a, ebiten.FilterNearest)
|
|
if err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Masking (Ebiten Demo)"); err != nil {
|
|
log.Fatal(err)
|
|
}
|
|
}
|