mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-25 03:08:54 +01:00
115 lines
2.6 KiB
Go
115 lines
2.6 KiB
Go
// Copyright 2014 Hajime Hoshi
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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 jsgo
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package main
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import (
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"fmt"
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"image"
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"image/color"
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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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count int
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brushImage *ebiten.Image
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canvasImage *ebiten.Image
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)
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func init() {
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const (
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a0 = 0x40
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a1 = 0xc0
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a2 = 0xff
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)
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pixels := []uint8{
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a0, a1, a1, a0,
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a1, a2, a2, a1,
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a1, a2, a2, a1,
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a0, a1, a1, a0,
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}
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brushImage, _ = ebiten.NewImageFromImage(&image.Alpha{
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Pix: pixels,
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Stride: 4,
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Rect: image.Rect(0, 0, 4, 4),
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}, ebiten.FilterDefault)
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canvasImage, _ = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterDefault)
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canvasImage.Fill(color.White)
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}
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// paint draws the brush on the given canvas image at the position (x, y).
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func paint(canvas *ebiten.Image, x, y int) {
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Translate(float64(x), float64(y))
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// Scale the color and rotate the hue so that colors vary on each frame.
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op.ColorM.Scale(1.0, 0.50, 0.125, 1.0)
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tps := ebiten.TPS()
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theta := 2.0 * math.Pi * float64(count%tps) / float64(tps)
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op.ColorM.RotateHue(theta)
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canvas.DrawImage(brushImage, op)
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}
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func update(screen *ebiten.Image) error {
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drawn := false
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// Paint the brush by mouse dragging
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mx, my := ebiten.CursorPosition()
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if ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) {
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paint(canvasImage, mx, my)
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drawn = true
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}
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// Paint the brush by touches
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for _, t := range ebiten.TouchIDs() {
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x, y := ebiten.TouchPosition(t)
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paint(canvasImage, x, y)
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drawn = true
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}
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if drawn {
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count++
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}
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if ebiten.IsDrawingSkipped() {
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return nil
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}
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screen.DrawImage(canvasImage, nil)
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msg := fmt.Sprintf("(%d, %d)", mx, my)
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for _, t := range ebiten.TouchIDs() {
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x, y := ebiten.TouchPosition(t)
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msg += fmt.Sprintf("\n(%d, %d) touch %d", x, y, t)
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}
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ebitenutil.DebugPrint(screen, msg)
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return nil
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}
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func main() {
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if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Paint (Ebiten Demo)"); err != nil {
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log.Fatal(err)
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}
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}
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