diff --git a/examples/infinitescroll/main.go b/examples/infinitescroll/main.go new file mode 100644 index 000000000..c5330a69a --- /dev/null +++ b/examples/infinitescroll/main.go @@ -0,0 +1,147 @@ +// Copyright 2016 The Ebiten Authors +// +// 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" + _ "image/png" + "log" + "math" + + "github.com/hajimehoshi/ebiten" + "github.com/hajimehoshi/ebiten/ebitenutil" +) + +const ( + screenWidth = 320 + screenHeight = 240 +) + +var ( + theViewport = &viewport{} + bgImage *ebiten.Image + repeatedBgImage *ebiten.Image + groundImage *ebiten.Image +) + +type viewport struct { + x16 int + y16 int +} + +func round(x float64) float64 { + return math.Floor(x + 0.5) +} + +func (p *viewport) Move() { + + w, h := bgImage.Size() + mx := w * 16 + my := h * 16 + + p.x16 += w / 32 + p.y16 += h / 32 + + for mx <= p.x16 { + p.x16 -= mx + } + for my <= p.y16 { + p.y16 -= my + } + for p.x16 < 0 { + p.x16 += mx + } + for p.y16 < 0 { + p.y16 += my + } +} + +func (p *viewport) Position() (int, int) { + return p.x16, p.y16 +} + +func updateGroundImage(ground *ebiten.Image) error { + + if err := ground.Clear(); err != nil { + return err + } + + x16, y16 := theViewport.Position() + op := &ebiten.DrawImageOptions{} + op.GeoM.Translate(float64(-x16)/16, float64(-y16)/16) + if err := ground.DrawImage(repeatedBgImage, op); err != nil { + return err + } + return nil +} + +func drawGroundImage(screen *ebiten.Image, ground *ebiten.Image) error { + + op := &ebiten.DrawImageOptions{} + if err := screen.DrawImage(ground, op); err != nil { + return err + } + return nil +} + +func update(screen *ebiten.Image) error { + + theViewport.Move() + + if err := updateGroundImage(groundImage); err != nil { + return err + } + if err := drawGroundImage(screen, groundImage); err != nil { + return err + } + + msg := fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS()) + if err := ebitenutil.DebugPrint(screen, msg); err != nil { + return err + } + return nil +} + +func main() { + + var err error + bgImage, _, err = ebitenutil.NewImageFromFile("tile.png", ebiten.FilterNearest) + if err != nil { + log.Fatal(err) + } + w, h := bgImage.Size() + const repeat = 5 + repeatedBgImage, err = ebiten.NewImage(w*repeat, h*repeat, ebiten.FilterNearest) + if err != nil { + log.Fatal(err) + } + for j := 0; j < repeat; j++ { + for i := 0; i < repeat; i++ { + op := &ebiten.DrawImageOptions{} + op.GeoM.Translate(float64(w*i), float64(h*j)) + if err := repeatedBgImage.DrawImage(bgImage, op); err != nil { + log.Fatal(err) + } + } + } + groundImage, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest) + if err != nil { + log.Fatal(err) + } + + if err := ebiten.Run(update, screenWidth, screenHeight, 2, "infinite scroll"); err != nil { + log.Fatal(err) + } +} diff --git a/examples/infinitescroll/tile.png b/examples/infinitescroll/tile.png new file mode 100644 index 000000000..33c138f41 Binary files /dev/null and b/examples/infinitescroll/tile.png differ