mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 04:57:26 +01:00
110 lines
2.4 KiB
Go
110 lines
2.4 KiB
Go
// Copyright 2021 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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//go:build example
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// +build example
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package main
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import (
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"image/color"
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"log"
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"math/rand"
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"time"
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"github.com/hajimehoshi/ebiten/v2"
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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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scale = 64
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starsCount = 1024
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)
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type Star struct {
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fromx, fromy, tox, toy, brightness float32
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}
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func (s *Star) Init() {
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s.tox = rand.Float32() * screenWidth * scale
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s.fromx = s.tox
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s.toy = rand.Float32() * screenHeight * scale
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s.fromy = s.toy
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s.brightness = rand.Float32() * 0xff
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}
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func (s *Star) Update(x, y float32) {
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s.fromx = s.tox
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s.fromy = s.toy
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s.tox += (s.tox - x) / 32
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s.toy += (s.toy - y) / 32
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s.brightness += 1
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if 0xff < s.brightness {
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s.brightness = 0xff
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}
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if s.fromx < 0 || screenWidth*scale < s.fromx || s.fromy < 0 || screenHeight*scale < s.fromy {
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s.Init()
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}
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}
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func (s *Star) Draw(screen *ebiten.Image) {
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c := color.RGBA{
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R: uint8(0xbb * s.brightness / 0xff),
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G: uint8(0xdd * s.brightness / 0xff),
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B: uint8(0xff * s.brightness / 0xff),
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A: 0xff}
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vector.StrokeLine(screen, s.fromx/scale, s.fromy/scale, s.tox/scale, s.toy/scale, 1, c)
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}
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type Game struct {
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stars [starsCount]Star
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}
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func NewGame() *Game {
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g := &Game{}
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for i := 0; i < starsCount; i++ {
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g.stars[i].Init()
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}
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return g
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}
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func (g *Game) Update() error {
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x, y := ebiten.CursorPosition()
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for i := 0; i < starsCount; i++ {
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g.stars[i].Update(float32(x*scale), float32(y*scale))
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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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for i := 0; i < starsCount; i++ {
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g.stars[i].Draw(screen)
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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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rand.Seed(time.Now().UnixNano())
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ebiten.SetWindowSize(screenWidth, screenHeight)
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ebiten.SetWindowTitle("Stars (Ebitengine Demo)")
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if err := ebiten.RunGame(NewGame()); err != nil {
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log.Fatal(err)
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}
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}
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