mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-26 11:48:55 +01:00
93 lines
2.7 KiB
Go
93 lines
2.7 KiB
Go
// Copyright 2018 The Ebiten 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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// +build example jsgo
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package main
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import (
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"bytes"
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"image"
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_ "image/jpeg"
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"log"
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"github.com/hajimehoshi/ebiten/v2"
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"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
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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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var (
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gophersImage *ebiten.Image
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)
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type Game struct{}
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func (g *Game) Update() error {
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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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op := &ebiten.DrawImageOptions{}
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op.GeoM.Translate(0, 0)
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screen.DrawImage(gophersImage, op)
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// Box blur (7x7)
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// https://en.wikipedia.org/wiki/Box_blur
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for j := -3; j <= 3; j++ {
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for i := -3; i <= 3; i++ {
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Translate(float64(i), 244+float64(j))
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// Alpha scale should be 1.0/49.0, but accumulating 1/49 49 times doesn't reach to 1, because
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// the final color is affected by the destination alpha when CompositeModeSourceOver is used.
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// This composite mode is the default mode. See how this is calculated at the doc:
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// https://pkg.go.dev/github.com/hajimehoshi/ebiten/v2#CompositeMode
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//
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// Use a higher value than 1.0/49.0. Here, 1.0/25.0 here to get a reasonable result.
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op.ColorM.Scale(1, 1, 1, 1.0/25.0)
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screen.DrawImage(gophersImage, op)
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}
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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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// Decode image from a byte slice instead of a file so that
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// this example works in any working directory.
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// If you want to use a file, there are some options:
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// 1) Use os.Open and pass the file to the image decoder.
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// This is a very regular way, but doesn't work on browsers.
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// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
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// This works even on browsers.
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// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
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// This also works on browsers.
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img, _, err := image.Decode(bytes.NewReader(images.FiveYears_jpg))
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if err != nil {
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log.Fatal(err)
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}
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gophersImage, _ = ebiten.NewImageFromImage(img)
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ebiten.SetWindowSize(screenWidth, screenHeight)
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ebiten.SetWindowTitle("Blur (Ebiten Demo)")
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if err := ebiten.RunGame(&Game{}); err != nil {
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log.Fatal(err)
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}
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}
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