Merge jalen's changes

main.go

@@ -42,24 +42,34 @@ func run() {
 	if err != nil {
 		panic(err)
 	}
+	//batch := pixel.NewBatch(&pixel.TrianglesData{}, spritesheet)
 
 	background, err := loadPicture("background.png")
 
 	if err != nil {
 		panic(err)
 	}
+	bg := pixel.NewSprite(background, background.Bounds())
 	//batch := pixel.NewBatch(&pixel.TrianglesData{}, spritesheet)
 
+	/*
+		When creating the sprite, you need to know big each frame is inside the spritesheet.
+		If you use aseprite or some other pixel art program, you can find the number of pixels
+		within each frame. For our sprite sheet, each frame is 96 px wide and 96 px high. So
+		we increment it by 96 for both x and y so that it can get the position of the frame
+		at the bottom right corner.
+	*/
 	var spritesFrames []pixel.Rect
-	for x := spritesheet.Bounds().Min.X; x < spritesheet.Bounds().Max.X; x += 32 {
+	for x := spritesheet.Bounds().Min.X; x < spritesheet.Bounds().Max.X; x += 96 {
-		for y := spritesheet.Bounds().Min.Y; y < spritesheet.Bounds().Max.Y; y += 32 {
+		for y := spritesheet.Bounds().Min.Y; y < spritesheet.Bounds().Max.Y; y += 96 {
-			spritesFrames = append(spritesFrames, pixel.R(x, y, x+79, y+92))
+			spritesFrames = append(spritesFrames, pixel.R(x, y, x+96, y+96)) // (x, y, width, height) of frame
 		}
 	}
+	Sprite := pixel.NewSprite(spritesheet, spritesFrames[3])
 
 	var (
 		camPos = pixel.ZV
-		camSpeed     = 500.0
+		//camSpeed     = 500.0
 		camZoom      = 0.3
 		camZoomSpeed = 1.2
 	)
@@ -78,44 +88,75 @@ func run() {
 		}
 	)
 
-	last := time.Now()
+	var fps int64 = 60
+	timePerFrame := 1000000000 / fps
+	var lastTime int64 = time.Now().UnixNano()
+	var now int64
+	var dt int64
+
+	// Game Loop
 	for !win.Closed() {
-		dt := time.Since(last).Seconds()
+		now = time.Now().UnixNano()
-		last = time.Now()
+		dt += (now - lastTime)
+		lastTime = time.Now().UnixNano()
+
+		//Execute a frame.
+		if dt >= timePerFrame {
+
+			// *** Update begins *** //
 
 			playerXY = pixel.Vec{
 				playerX,
 				playerY,
 			}
 			cam := pixel.IM.Scaled(camPos, camZoom).Moved(win.Bounds().Center().Sub(camPos))
+
 			win.SetMatrix(cam)
-		bg := pixel.NewSprite(background, background.Bounds())
+			/*
-		Sprite := pixel.NewSprite(spritesheet, spritesFrames[3])
+				This is where Sprite and bg was originally. Creating them over and over inside
+				the main loop is not very good resource management. When i added my own dt, the game was
+				only going about 22 fps, when it should've been going 60. I moved them
+				out of the loop and created them up top. It fixed it and now runs faster.
+
+				the tutorial only has it in the loop with the exception that it creates it only
+				if you click the button to make a tree. It only created it once and added it.
+			*/
+
 			//mouse := cam.Unproject(win.MousePosition())
+
+			speed := 2.0
+			if win.Pressed(pixelgl.KeyA) { //left
+				playerX -= speed
+				Sprite.Set(spritesheet, spritesFrames[2])
+			}
+			if win.Pressed(pixelgl.KeyD) { //Right
+				playerX += speed
+				Sprite.Set(spritesheet, spritesFrames[1])
+			}
+			if win.Pressed(pixelgl.KeyS) { //Down
+				playerY -= speed
+				Sprite.Set(spritesheet, spritesFrames[3])
+			}
+			if win.Pressed(pixelgl.KeyW) { //up
+				playerY += speed
+				Sprite.Set(spritesheet, spritesFrames[0])
+			}
+			camPos.X = playerX
+			camPos.Y = playerY
+			camZoom *= math.Pow(camZoomSpeed, win.MouseScroll().Y)
+
+			// *** Update Ends *** //
+
+			// *** Render begin *** //
 			win.Clear(colornames.Forestgreen)
 			bg.Draw(win, pixel.IM.Moved(win.Bounds().Center()))
 			Sprite.Draw(win, pixel.IM.Scaled(pixel.ZV, 4).Moved(playerXY))
-		if win.Pressed(pixelgl.KeyA) {
-			playerX -= camSpeed * dt
-
-		}
-
-		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()
 
+			// *** Render End *** //
+
 			frames++
 			select {
 			case <-second:
@@ -125,6 +166,7 @@ func run() {
 			}
 		}
 	}
+}
 
 func main() {
 	pixelgl.Run(run)