Bind camera and sprite

main.go

@@ -1,29 +1,25 @@
-// main
 package main
 
 import (
+	"fmt"
 	"image"
-	_ "image/png"
-	"math/rand"
+	"math"
 	"os"
 	"time"
 
+	_ "image/png"
+
 	"github.com/faiface/pixel"
 	"github.com/faiface/pixel/pixelgl"
 	"golang.org/x/image/colornames"
 )
 
-//open file from the system
 func loadPicture(path string) (pixel.Picture, error) {
 	file, err := os.Open(path)
 	if err != nil {
 		return nil, err
 	}
-
-	//user 'defer' to close the file later on
 	defer file.Close()
-
-	//decode the file to find it's type
 	img, _, err := image.Decode(file)
 	if err != nil {
 		return nil, err
@@ -31,16 +27,12 @@ func loadPicture(path string) (pixel.Picture, error) {
 	return pixel.PictureDataFromImage(img), nil
 }
 
-//Pixel's main function (because GO forced them to do it this way)
 func run() {
-	//set the Window parameters
 	cfg := pixelgl.WindowConfig{
 		Title:  "Pixel Rocks!",
 		Bounds: pixel.R(0, 0, 1024, 768),
 		VSync:  true,
 	}
-
-	//create a window and pass the parameters
 	win, err := pixelgl.NewWindow(cfg)
 	if err != nil {
 		panic(err)
@@ -51,6 +43,13 @@ func run() {
 		panic(err)
 	}
 
+	background, err := loadPicture("background.png")
+
+	if err != nil {
+		panic(err)
+	}
+	//batch := pixel.NewBatch(&pixel.TrianglesData{}, spritesheet)
+
 	var treesFrames []pixel.Rect
 	for x := spritesheet.Bounds().Min.X; x < spritesheet.Bounds().Max.X; x += 32 {
 		for y := spritesheet.Bounds().Min.Y; y < spritesheet.Bounds().Max.Y; y += 32 {
@@ -58,52 +57,72 @@ func run() {
 		}
 	}
 
-	//camera
 	var (
-		camPos   = pixel.ZV
-		camSpeed = 500.0
-		trees    []*pixel.Sprite
-		matrices []pixel.Matrix
+		camPos       = pixel.ZV
+		camSpeed     = 500.0
+		camZoom      = 1.0
+		camZoomSpeed = 1.2
+	)
+
+	var (
+		frames = 0
+		second = time.Tick(time.Second)
+	)
+	playerX := win.Bounds().Max.X / 2
+	playerY := win.Bounds().Max.Y / 2
+
+	var (
+		playerXY = pixel.Vec{
+			playerX,
+			playerY,
+		}
 	)
 
 	last := time.Now()
-	//loop until window is closed by "X" button
 	for !win.Closed() {
 		dt := time.Since(last).Seconds()
 		last = time.Now()
 
-		cam := pixel.IM.Moved(win.Bounds().Center().Sub(camPos))
+		playerXY = pixel.Vec{
+			playerX,
+			playerY,
+		}
+		cam := pixel.IM.Scaled(camPos, camZoom).Moved(win.Bounds().Center().Sub(camPos))
 		win.SetMatrix(cam)
-
-		if win.JustPressed(pixelgl.MouseButtonLeft) {
-			tree := pixel.NewSprite(spritesheet, treesFrames[rand.Intn(len(treesFrames))])
-			trees = append(trees, tree)
-			mouse := cam.Unproject(win.MousePosition())
-			matrices = append(matrices, pixel.IM.Scaled(pixel.ZV, 4).Moved(mouse))
-		}
-
-		if win.Pressed(pixelgl.KeyA) {
-			camPos.X -= camSpeed * dt
-		}
-
-		if win.Pressed(pixelgl.KeyD) {
-			camPos.X += camSpeed * dt
-		}
-
-		if win.Pressed(pixelgl.KeyS) {
-			camPos.Y -= camSpeed * dt
-		}
-
-		if win.Pressed(pixelgl.KeyW) {
-			camPos.Y += camSpeed * dt
-		}
-		//refresh screen and set background color
+		bg := pixel.NewSprite(background, background.Bounds())
+		tree := pixel.NewSprite(spritesheet, treesFrames[0])
+		//mouse := cam.Unproject(win.MousePosition())
 		win.Clear(colornames.Forestgreen)
-		for i, tree := range trees {
-			tree.Draw(win, matrices[i])
+		bg.Draw(win, pixel.IM.Moved(win.Bounds().Center()))
+		tree.Draw(win, pixel.IM.Scaled(pixel.ZV, 4).Moved(playerXY))
+		if win.Pressed(pixelgl.KeyA) {
+			playerX -= camSpeed * dt
+
 		}
-		//update the window
+
+		camPos.X = playerX
+		camPos.Y = playerY
+		if win.Pressed(pixelgl.KeyD) {
+			playerX += camSpeed * dt
+		}
+		if win.Pressed(pixelgl.KeyS) {
+			playerY -= camSpeed * dt
+		}
+		if win.Pressed(pixelgl.KeyW) {
+			playerY += camSpeed * dt
+		}
+		camZoom *= math.Pow(camZoomSpeed, win.MouseScroll().Y)
+
+		//batch.Draw(win)
 		win.Update()
+
+		frames++
+		select {
+		case <-second:
+			win.SetTitle(fmt.Sprintf("%s | FPS: %d", cfg.Title, frames))
+			frames = 0
+		default:
+		}
 	}
 }