ebiten/examples/camera/main.go

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// Copyright 2020 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.
// +build example jsgo
package main
import (
"bytes"
"fmt"
"image"
_ "image/png"
"log"
"math"
"golang.org/x/image/math/f64"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
"github.com/hajimehoshi/ebiten/examples/resources/images"
)
const (
screenWidth = 320
screenHeight = 240
)
const (
tileSize = 16
tileXNum = 25
)
const (
worldWidth = 480
worldHeight = 320
worldSizeX = worldWidth / tileSize
)
var (
tilesImage *ebiten.Image
)
func init() {
// Decode image from a byte slice instead of a file so that
// this example works in any working directory.
// If you want to use a file, there are some options:
// 1) Use os.Open and pass the file to the image decoder.
// This is a very regular way, but doesn't work on browsers.
// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
// This works even on browsers.
// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
// This also works on browsers.
img, _, err := image.Decode(bytes.NewReader(images.Tiles_png))
if err != nil {
log.Fatal(err)
}
tilesImage, _ = ebiten.NewImageFromImage(img, ebiten.FilterDefault)
}
type Camera struct {
ViewPort f64.Vec2
Position f64.Vec2
ZoomFactor int
Rotation int
}
func (c *Camera) String() string {
return fmt.Sprintf(
"T: %.1f, R: %d, S: %d",
c.Position, c.Rotation, c.ZoomFactor,
)
}
func (c *Camera) viewportCenter() f64.Vec2 {
return f64.Vec2{
c.ViewPort[0] * 0.5,
c.ViewPort[1] * 0.5,
}
}
func (c *Camera) worldMatrix() ebiten.GeoM {
m := ebiten.GeoM{}
m.Translate(-c.Position[0], -c.Position[1])
// We want to scale and rotate around center of image / screen
m.Translate(-c.viewportCenter()[0], -c.viewportCenter()[1])
m.Scale(
math.Pow(1.01, float64(c.ZoomFactor)),
math.Pow(1.01, float64(c.ZoomFactor)),
)
m.Rotate(float64(c.Rotation) * 2 * math.Pi / 360)
m.Translate(c.viewportCenter()[0], c.viewportCenter()[1])
return m
}
func (c *Camera) Render(world, screen *ebiten.Image) error {
return screen.DrawImage(world, &ebiten.DrawImageOptions{
GeoM: c.worldMatrix(),
})
}
func (c *Camera) ScreenToWorld(posX, posY int) (float64, float64) {
inverseMatrix := c.worldMatrix()
if inverseMatrix.IsInvertible() {
inverseMatrix.Invert()
return inverseMatrix.Apply(float64(posX), float64(posY))
} else {
// When scaling it can happend that matrix is not invertable
return math.NaN(), math.NaN()
}
}
func (c *Camera) Reset() {
c.Position[0] = 0
c.Position[1] = 0
c.Rotation = 0
c.ZoomFactor = 0
}
type Game struct {
layers [][]int
world *ebiten.Image
camera Camera
}
func (g *Game) Update(screen *ebiten.Image) error {
if ebiten.IsKeyPressed(ebiten.KeyA) || ebiten.IsKeyPressed(ebiten.KeyLeft) {
g.camera.Position[0] -= 1
}
if ebiten.IsKeyPressed(ebiten.KeyD) || ebiten.IsKeyPressed(ebiten.KeyRight) {
g.camera.Position[0] += 1
}
if ebiten.IsKeyPressed(ebiten.KeyW) || ebiten.IsKeyPressed(ebiten.KeyUp) {
g.camera.Position[1] -= 1
}
if ebiten.IsKeyPressed(ebiten.KeyS) || ebiten.IsKeyPressed(ebiten.KeyDown) {
g.camera.Position[1] += 1
}
if ebiten.IsKeyPressed(ebiten.KeyQ) {
g.camera.ZoomFactor -= 1
}
if ebiten.IsKeyPressed(ebiten.KeyE) {
g.camera.ZoomFactor += 1
}
if ebiten.IsKeyPressed(ebiten.KeyR) {
g.camera.Rotation += 1
}
if ebiten.IsKeyPressed(ebiten.KeySpace) {
g.camera.Reset()
}
return nil
}
func (g *Game) Draw(screen *ebiten.Image) {
// Draw each tile with each DrawImage call.
// As the source images of all DrawImage calls are always same,
// this rendering is done very effectively.
// For more detail, see https://pkg.go.dev/github.com/hajimehoshi/ebiten#Image.DrawImage
for _, l := range g.layers {
for i, t := range l {
op := &ebiten.DrawImageOptions{}
op.GeoM.Translate(float64((i%worldSizeX)*tileSize), float64((i/worldSizeX)*tileSize))
sx := (t % tileXNum) * tileSize
sy := (t / tileXNum) * tileSize
g.world.DrawImage(tilesImage.SubImage(image.Rect(sx, sy, sx+tileSize, sy+tileSize)).(*ebiten.Image), op)
}
}
g.camera.Render(g.world, screen)
worldX, worldY := g.camera.ScreenToWorld(ebiten.CursorPosition())
ebitenutil.DebugPrint(
screen,
fmt.Sprintf("TPS: %0.2f\nMove (WASD/Arrows)\nZoom (QE)\nRotate (R)\nReset (Space)", ebiten.CurrentTPS()),
)
ebitenutil.DebugPrintAt(
screen,
fmt.Sprintf("%s\nCursor World Pos: %.2f,%.2f",
g.camera.String(),
worldX, worldY),
0, screenHeight-32,
)
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func main() {
g := &Game{
layers: [][]int{
{
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243,
243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 244, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 244, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 219, 243, 243, 243, 219, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 244, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 218, 243, 243, 243,
243, 218, 243, 243, 243, 243, 243, 243, 243, 243, 243, 244, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243, 243,
},
{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 26, 27, 28, 29, 30, 31, 0, 0, 0, 0, 0, 0, 0, 0, 0, 63, 64, 65, 66, 67, 68, 0, 0, 0, 0,
0, 0, 0, 0, 0, 51, 52, 53, 54, 55, 56, 0, 0, 0, 0, 0, 0, 0, 0, 0, 88, 89, 90, 91, 92, 93, 0, 0, 0, 0,
0, 0, 0, 0, 0, 76, 77, 78, 79, 80, 81, 0, 0, 0, 0, 0, 0, 0, 0, 0, 113, 114, 115, 116, 117, 118, 0, 0, 0, 0,
0, 0, 0, 0, 0, 101, 102, 103, 104, 105, 106, 0, 0, 0, 0, 0, 0, 0, 0, 0, 138, 139, 140, 141, 142, 143, 0, 0, 0, 0,
0, 0, 0, 0, 0, 126, 127, 128, 129, 130, 131, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 288, 0, 0, 0, 0,
0, 0, 0, 0, 0, 303, 303, 245, 242, 303, 303, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 45, 46, 47, 48,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 70, 71, 72, 73,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 95, 96, 97, 98,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 120, 121, 122, 123,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 145, 146, 147, 148,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 267, 268, 268, 268, 268, 268, 268, 268, 268, 268, 268, 268, 268, 268, 268, 270, 242, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 192, 193, 193, 193, 193, 193, 193, 193, 193, 193, 193, 193, 193, 193, 193, 193, 222, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 245, 242, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
},
},
camera: Camera{ViewPort: f64.Vec2{screenWidth, screenHeight}},
}
g.world, _ = ebiten.NewImage(worldWidth, worldHeight, ebiten.FilterDefault)
ebiten.SetWindowSize(screenWidth*2, screenHeight*2)
ebiten.SetWindowTitle("Tiles (Ebiten Demo)")
if err := ebiten.RunGame(g); err != nil {
log.Fatal(err)
}
}