ebiten/examples/lasttouch/main.go
2022-11-03 20:24:09 +09:00

85 lines
2.5 KiB
Go

// Copyright 2022 The Ebitengine 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"
"log"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/ebitenutil"
"github.com/hajimehoshi/ebiten/v2/inpututil"
)
const (
screenWidth = 640
screenHeight = 480
)
type pos struct {
x int
y int
}
type Game struct {
releasedTouchIDs []ebiten.TouchID
lastTouchPositions []pos
}
func (g *Game) Update() error {
// In general, Append* function allocates a new slice if the given slice doesn't have enough capacity,
// or otherwise, just extends the length of the given slice.
//
// This example passes an empty slice that might have a capacity in order to reduce the chances of slice allocations.
// You can also pass 'nil' to AppendJustReleasedTouchIDs if you don't care the cost of creating slices.
// In this case, AppendJustReleasedTouchIDs would always create a new slice.
g.releasedTouchIDs = inpututil.AppendJustReleasedTouchIDs(g.releasedTouchIDs[:0])
for _, id := range g.releasedTouchIDs {
// Get the last position of the touch.
// ebiten.TouchPosition would not work as the touch has already gone in this tick.
x, y := inpututil.TouchPositionInPreviousTick(id)
g.lastTouchPositions = append(g.lastTouchPositions, pos{x: x, y: y})
}
const n = 10
if len(g.lastTouchPositions) > n {
copy(g.lastTouchPositions, g.lastTouchPositions[len(g.lastTouchPositions)-n:])
g.lastTouchPositions = g.lastTouchPositions[:n]
}
return nil
}
func (g *Game) Draw(screen *ebiten.Image) {
msg := "Touch the screen and release your finger from it.\n\nLast Positions:\n"
for _, p := range g.lastTouchPositions {
msg += fmt.Sprintf(" (%d, %d)\n", p.x, p.y)
}
ebitenutil.DebugPrint(screen, msg)
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func main() {
ebiten.SetWindowSize(screenWidth, screenHeight)
ebiten.SetWindowTitle("Last Touch Positions (Ebitengine Demo)")
if err := ebiten.RunGame(&Game{}); err != nil {
log.Fatal(err)
}
}