mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-26 03:38:55 +01:00
144 lines
3.0 KiB
Go
144 lines
3.0 KiB
Go
// Copyright 2016 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
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package main
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import (
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"fmt"
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_ "image/png"
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"log"
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"math"
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"github.com/hajimehoshi/ebiten"
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"github.com/hajimehoshi/ebiten/ebitenutil"
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)
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const (
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screenWidth = 320
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screenHeight = 240
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)
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var (
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theViewport = &viewport{}
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bgImage *ebiten.Image
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repeatedBgImage *ebiten.Image
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groundImage *ebiten.Image
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)
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type viewport struct {
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x16 int
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y16 int
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}
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func round(x float64) float64 {
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return math.Floor(x + 0.5)
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}
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func (p *viewport) Move() {
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w, h := bgImage.Size()
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mx := w * 16
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my := h * 16
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p.x16 += w / 32
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p.y16 += h / 32
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for mx <= p.x16 {
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p.x16 -= mx
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}
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for my <= p.y16 {
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p.y16 -= my
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}
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for p.x16 < 0 {
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p.x16 += mx
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}
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for p.y16 < 0 {
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p.y16 += my
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}
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}
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func (p *viewport) Position() (int, int) {
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return p.x16, p.y16
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}
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func updateGroundImage(ground *ebiten.Image) error {
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if err := ground.Clear(); err != nil {
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return err
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}
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x16, y16 := theViewport.Position()
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Translate(float64(-x16)/16, float64(-y16)/16)
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if err := ground.DrawImage(repeatedBgImage, op); err != nil {
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return err
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}
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return nil
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}
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func drawGroundImage(screen *ebiten.Image, ground *ebiten.Image) error {
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op := &ebiten.DrawImageOptions{}
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if err := screen.DrawImage(ground, op); err != nil {
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return err
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}
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return nil
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}
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func update(screen *ebiten.Image) error {
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theViewport.Move()
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if err := updateGroundImage(groundImage); err != nil {
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return err
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}
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if err := drawGroundImage(screen, groundImage); err != nil {
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return err
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}
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msg := fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS())
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if err := ebitenutil.DebugPrint(screen, msg); err != nil {
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return err
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}
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return nil
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}
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func main() {
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var err error
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bgImage, _, err = ebitenutil.NewImageFromFile("_resources/images/tile.png", ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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w, h := bgImage.Size()
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const repeat = 5
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repeatedBgImage, err = ebiten.NewImage(w*repeat, h*repeat, ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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for j := 0; j < repeat; j++ {
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for i := 0; i < repeat; i++ {
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Translate(float64(w*i), float64(h*j))
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if err := repeatedBgImage.DrawImage(bgImage, op); err != nil {
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log.Fatal(err)
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}
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}
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}
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groundImage, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
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if err != nil {
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log.Fatal(err)
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}
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if err := ebiten.Run(update, screenWidth, screenHeight, 2, "infinite scroll"); err != nil {
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log.Fatal(err)
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}
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}
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