针对项目开发中，图形围绕中心旋转的问题（Go语言源代码）

// Copyright 2014 Hajime Hoshi
//
// 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 (
"bytes"
"image"
_ "image/jpeg"
"log"
"math"

"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
)

const (
screenWidth  = 640
screenHeight = 480
)

var (
gophersImage *ebiten.Image
)

type Game struct {
count int
}

func (g *Game) Update() error {
g.count++
return nil
}

func (g *Game) Draw(screen *ebiten.Image) {
s := gophersImage.Bounds().Size()
op := &ebiten.DrawImageOptions{}

// Move the image's center to the screen's upper-left corner.
// This is a preparation for rotating. When geometry matrices are applied,
// the origin point is the upper-left corner.
op.GeoM.Translate(-float64(s.X)/2, -float64(s.Y)/2)

// Rotate the image. As a result, the anchor point of this rotate is
// the center of the image.
op.GeoM.Rotate(float64(g.count%360) * 2 * math.Pi / 360)

// Move the image to the screen's center.
op.GeoM.Translate(screenWidth/2, screenHeight/2)

screen.DrawImage(gophersImage, op)
}

func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}

func main() {
// Decode an image from the image file's byte slice.
img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
if err != nil {
log.Fatal(err)
}
gophersImage = ebiten.NewImageFromImage(img)

ebiten.SetWindowSize(screenWidth, screenHeight)
ebiten.SetWindowTitle("Rotate (Ebitengine Demo)")
if err := ebiten.RunGame(&Game{}); err != nil {
log.Fatal(err)
}
}

更多的一些游戏项目功能后续会在本人Github上完善：

ForwardGlimpses (joesx) (github.com)

原文地址：https://blog.csdn.net/weixin_74088105/article/details/136826039

免责声明：本站文章内容转载自网络资源，如本站内容侵犯了原著者的合法权益，可联系本站删除。更多内容请关注自学内容网（zxcms.com）！