ebiten/examples/dragmascot/main.go

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// Copyright 2024 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.
// Mascot is a desktop mascot on cross platforms.
// This is inspired by mattn's gopher (https://github.com/mattn/gopher).
package main
import (
"bytes"
"image"
_ "image/png"
"log"
"github.com/hajimehoshi/ebiten/v2"
rmascot "github.com/hajimehoshi/ebiten/v2/examples/resources/images/mascot"
"github.com/hajimehoshi/ebiten/v2/inpututil"
)
const (
width = 200
height = 200
)
var (
gopher1 *ebiten.Image
gopher2 *ebiten.Image
gopher3 *ebiten.Image
)
func init() {
// Decode an image from the image file's byte slice.
img1, _, err := image.Decode(bytes.NewReader(rmascot.Out01_png))
if err != nil {
log.Fatal(err)
}
gopher1 = ebiten.NewImageFromImage(img1)
img2, _, err := image.Decode(bytes.NewReader(rmascot.Out02_png))
if err != nil {
log.Fatal(err)
}
gopher2 = ebiten.NewImageFromImage(img2)
img3, _, err := image.Decode(bytes.NewReader(rmascot.Out03_png))
if err != nil {
log.Fatal(err)
}
gopher3 = ebiten.NewImageFromImage(img3)
}
type mascot struct {
count int
dragging bool
dragStartWindowX int
dragStartWindowY int
dragStartCursorX int
dragStartCursorY int
cursorToWindowX float64
cursorToWindowY float64
}
func (m *mascot) Layout(outsideWidth, outsideHeight int) (int, int) {
// The cursor position is in a "logical" coordinate, which is determined by the game width and height.
// Calculate the factors to convert a cursor position to a window position.
m.cursorToWindowX = float64(outsideWidth) / float64(width)
m.cursorToWindowY = float64(outsideHeight) / float64(height)
return width, height
}
func (m *mascot) Update() error {
if !ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
m.dragging = false
}
if !m.dragging && inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) {
m.dragging = true
m.dragStartWindowX, m.dragStartWindowY = ebiten.WindowPosition()
m.dragStartCursorX, m.dragStartCursorY = ebiten.CursorPosition()
}
if m.dragging {
// Move the window only by the delta of the cursor.
cx, cy := ebiten.CursorPosition()
dx := int(float64(cx-m.dragStartCursorX) * m.cursorToWindowX)
dy := int(float64(cy-m.dragStartCursorY) * m.cursorToWindowY)
wx, wy := ebiten.WindowPosition()
ebiten.SetWindowPosition(wx+dx, wy+dy)
m.count++
}
return nil
}
func (m *mascot) Draw(screen *ebiten.Image) {
img := gopher1
if m.dragging {
switch (m.count / 3) % 4 {
case 0:
img = gopher1
case 1, 3:
img = gopher2
case 2:
img = gopher3
}
}
screen.DrawImage(img, nil)
}
func main() {
ebiten.SetWindowDecorated(false)
ebiten.SetWindowFloating(true)
ebiten.SetWindowSize(width, height)
op := &ebiten.RunGameOptions{}
op.ScreenTransparent = true
op.SkipTaskbar = true
if err := ebiten.RunGameWithOptions(&mascot{}, op); err != nil {
log.Fatal(err)
}
}