I am creating a game in which asteroids spawn and move down the screen. In the update method of the game, i am using a random number to spawn the asteroids sporatically. When i start it up, it begins to lag within the first 5 seconds. I can see this because the score counter(which goes up every tick) starts going in intervals of 30. Also, the images of the asteroid do not even show up.
Here is the gameObject class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;
namespace thedodger
{
public abstract class gameObject
{
public static Texture2D texture;
public Rectangle rectangle;
public abstract void Draw(SpriteBatch spriteBatch);
public abstract void Update(GameTime gameTime);
}
}
here is the asteroid class;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;
namespace thedodger
{
public class Asteroid : gameObject
{
Random rand = new Random(1);
int yPos = -10;
public override void Draw(SpriteBatch spriteBatch)
{
spriteBatch.Begin();
spriteBatch.Draw(texture, new Rectangle(rand.Next(32,400), yPos,32,32),Color.White);
spriteBatch.End();
}
public override void Update(GameTime gameTime)
{
yPos--;
}
}
}
and here is the game1 class:
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;
namespace thedodger
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
int scorevalue = 0;
SpriteFont font;
player player1 = new player();
List<gameObject> objectList = new List<gameObject>();
Random rand = new Random(1);
Asteroid asteroid = new Asteroid();
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
font = Content.Load<SpriteFont>("font");
//player1.image = Content.Load<Texture2D>("EnemyShip005.png");
gameObject.texture = Content.Load<Texture2D>("asteroid");
// TODO: use this.Content to load your game content here
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
scorevalue++;
if (rand.Next(0, 8) == 2)
{
for (int i = 0; i < 30; i++)
{
objectList.Add(asteroid);
}
}
foreach (Asteroid asteroid in objectList)
{
asteroid.Update(gameTime);
asteroid.Draw(spriteBatch);
}
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
// TODO: Add your update logic here
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
// TODO: Add your drawing code here
spriteBatch.Begin();
spriteBatch.DrawString(font, "Score: " + scorevalue, new Vector2(5, 5), Color.White);
spriteBatch.End();
base.Draw(gameTime);
}
}
}
All help would be greatly appreciated.
sorry about the code. I am having difficult setting it up. Help on that too please.
As Tobias said, you probably should have put this on the Game Dev site and you appear to only have one Asteroid instantiated. In the Game1 object, you declare and instantiate an Asteroid object. Then in the Update method you add it repeatedly to the objectList. To get what I think you want, you should change
Asteroid asteroid = new Asteroid();
to
Asteroid asteroid;
Then change
for (int i = 0; i < 30; i++)
{
objectList.Add(asteroid);
}
to
for (int i = 0; i < 30; i++)
{
asteroid = new Asteroid();
objectList.Add(asteroid);
}
In your original code you declare and instantiate asteroid as a specific Asteroid but then never change it. So, throughout the whole program asteroid is pointed to one specific instance of an Asteroid. Then you repeatedly add asteroid to the objectList. So after each frame, 30 new references to the same asteroid object are being added to the objectList and the Update() and Draw() methods are being called on asteroid for every reference to it in objectList. So after 30 frames, one second if running at 30FPS, up to 900 references to the same exact asteroid object are in objectList and on that 30th frame asteroid is having its Update() and Draw() methods called up to 900 times. I'm pretty sure this is the source of your lag. Doing the corrections given above will result in objectList being populated with up to 900 different Asteroids, but will certainly experience lag as well. What you need to do as well is add a limit to the amount of asteroids on screen at any given time (the length of objectList can only be x amount) and/or lower the amount of asteroids created each time. I would suggest something like
for (int i = 0; i < 5; i++)
{
if (objectList.Count < 50) // Maximum asteroids on screen
{
asteroid = new Asteroid();
objectList.Add(asteroid);
}
}
will result in only five new asteroids for time and a maximum of 50 at any given time. If you add in functionality to destroy asteroids though, you'll have to remember to remove them from the objectList.
EDIT- As Neomex has said, your drawing is also a problem. I would suggest checking out the GDC 2008 talk on the XNA Framework performance here: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=6082
It very briefly covers some drawing and calculation performances and what you should/shouldn't do.
EDIT2- Actually, because of your random probability, it would be up to 900 object references and calls, not a full 900.
Try to make as least begin-end calls as possible, they often slow down game a lot.
( Asteroid class )
You are displaying graphics in your update function which is really bad thing.
If these fail, try to download newest drivers.
Reasuming:
Change in your asteroid class
public override void Draw(SpriteBatch spriteBatch)
{
spriteBatch.Begin();
spriteBatch.Draw(texture, new Rectangle(rand.Next(32,400), yPos,32,32),Color.White);
spriteBatch.End();
}
to
public override void Draw(SpriteBatch spriteBatch)
{
spriteBatch.Draw(texture, new Rectangle(rand.Next(32,400), yPos,32,32),Color.White);
}
Now in your update function
foreach (Asteroid asteroid in objectList)
{
asteroid.Update(gameTime);
asteroid.Draw(spriteBatch);
}
to
foreach (Asteroid asteroid in objectList)
{
asteroid.Update(gameTime);
}
And add this in draw function:
foreach (Asteroid asteroid in objectList)
{
asteroid.Draw(spriteBatch);
}
As Tobias has already pointed out, you are using the same asteriod object every time you want to spawn a new asteriod. You need to do add a new Asteriod() to the object list instead of using the same one.
Also, this code is mostly likely the reason you are suffering performance wise.
if (rand.Next(0, 8) == 2)
{
for (int i = 0; i < 30; i++)
{
objectList.Add(asteroid);
}
}
You are adding 30 instances of the same object to the collection on every update call (with is around 60 times a second). I realize you are using a random number, but it sill happens to about 12.5% of the update calls.
So within a 5-10 seconds, you now have thousands of these objects and are drawing the same image thousands and thousands of times.
Related
Here is the code from my MonoGame project where I have one player image in the bottom left corner and another player image in the top right. The goal is to use the left thumbstick on an Xbox 360 controller to move the player 1 on the left up and down. I used a break point and found that my controller is connected, but nothing happens when I use the thumbstick. Here is my code:
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
namespace _2PersonShooterGame_v0._1
{
/// <summary>
/// This is the main type for your game.
/// </summary>
public class Game1 : Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
// GamePad support
const float THUMB_STICK_DEFELCTION = 100;
//Window Resolution support
const int WINDOW_WIDTH = 1200;
const int WINDOW_HEIGHT = 800;
// player images and their rectabgles support
Texture2D player1;
Rectangle drawRect1;
Texture2D player2;
Rectangle drawRect2;
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
// Change resolution to 1200, 800
graphics.PreferredBackBufferWidth = WINDOW_WIDTH;
graphics.PreferredBackBufferHeight = WINDOW_HEIGHT;
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
// Load sprites
player1 = Content.Load<Texture2D>(#"graphics\sprite_player1");
player2 = Content.Load<Texture2D>(#"graphics\sprite_player2");
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// game-specific content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed || Keyboard.GetState().IsKeyDown(Keys.Escape))
Exit();
// Move player1 up and down using the thumbstick on an Xbox 360 remote
GamePadState gamepad = GamePad.GetState(PlayerIndex.One);
if (gamepad.IsConnected)
{
drawRect1.Y -= (int)(gamepad.ThumbSticks.Left.Y * THUMB_STICK_DEFELCTION);
}
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
// Drawing sprites in their respective rectangles
spriteBatch.Begin();
// Place player one in the bottom left corner and player two in the top right corner
drawRect1 = new Rectangle(0, WINDOW_HEIGHT - player1.Height, player1.Width, player1.Height);
drawRect2 = new Rectangle(WINDOW_WIDTH - player2.Width, 0, player2.Width, player2.Height);
spriteBatch.Draw(player1, drawRect1, Color.White);
spriteBatch.Draw(player2, drawRect2, Color.White);
spriteBatch.End();
base.Draw(gameTime);
}
}
}
The problem is that you're setting drawRect1.Y property in the Update(...) method but then again you're overriding this rectangle in your Draw(...) method.
// update
if (gamepad.IsConnected)
{
drawRect1.Y -= (int)(gamepad.ThumbSticks.Left.Y * THUMB_STICK_DEFELCTION);
}
// draw
drawRect1 = new Rectangle(0, WINDOW_HEIGHT - player1.Height, player1.Width, player1.Height);
What you should do i to just update rectangle in your Update(...) method and use the same ( updated ) value in Draw(...) call.
To fix this just remove this line : drawRect1 = new Rectangle(0, WINDOW_HEIGHT - player1.Height, player1.Width, player1.Height); from your Draw(...) method.
The game that i am making using C# is Square Chase. You mouse over the block and click it before it moves. The timer will count down in the back ground and the score will be raised by 1 each "tag" on the block. You can do the Project on XNA 4.0 Game Development by Example. This is 2010 C# and The project type is Windows Game (4.0).
Now I want to add extra stuff to it. I want take away 5 seconds of time every time they click on the block, but I don't know if its working so I need to make the time remaining visible. I want to make it smaller every time you hit the square.
Code: (under update and the if statement I have already done the subtraction on the time but would want to make sure its working by making it visible) Thank You
I need to find out how to sink and in large an image, I need to know how to show a float on the screen.
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace RFSquareChase
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
Random rand = new Random ();
Texture2D squareTexture;
Rectangle currentSquare;
int playerScore = 0;
float timeRemaining = 0.0f;
const float TimePerSquare = 0.75f;
Color [] colors = new Color[3] { Color.Red, Color.Green, Color.Blue };
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
base.Initialize();
this.IsMouseVisible = true;
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
squareTexture = Content.Load<Texture2D>(#"SQUARE");
// TODO: use this.Content to load your game content here
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
// TODO: Add your update logic here
if (timeRemaining == 0.0f)
{
currentSquare = new Rectangle(
rand.Next(0, this.Window.ClientBounds.Width - 25),
rand.Next(0, this.Window.ClientBounds.Height - 25),
25, 25);
timeRemaining = TimePerSquare;
}
MouseState mouse = Mouse.GetState();
if ((mouse.LeftButton == ButtonState.Pressed) &&
(currentSquare.Contains(mouse.X, mouse.Y)))
{
playerScore++;
timeRemaining = 0.0f;
timeRemaining = timeRemaining - 5;
}
timeRemaining = MathHelper.Max(0, timeRemaining - (float)gameTime.ElapsedGameTime.TotalSeconds);
this.Window.Title = "Score : " + playerScore.ToString();
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.Gray);
spriteBatch.Begin();
spriteBatch.Draw(
squareTexture,
currentSquare,
colors[playerScore % 3]);
spriteBatch.End();
// TODO: Add your drawing code here
base.Draw(gameTime);
}
}
}
To show a float on screen you simply use spriteBatch.DrawString, and could be useful Math.Round to show only the decimal you want. As you can see here.
To change the dimension of a sprite you can set the scale parameter in your spriteBatch.Draw. As you can see here
So I just started learning C# code a few months ago and I want to get a sprite in a full walk cycle.
I've got my walk cycle on a PNG image. Which is obviously a series of separate images showing the different stages of a walk cycle. Now I've got that into my Project/Solution I'm doing it as a Windows Game 4.0 in visual studio 2010.
And I'm fairly far on, so I've started trying to do srcRect and destRect set up. But all i've managed to get on screen is the image flicking left to right very fast and then infinitely going right. I achieved this by using the srcRect.X += srcRect.width line.
But what I want to do is have this move much slower. I want the destRect to move right on the screen when the thumbstick is pushed right and as this is happening I want it to flick right through my walk cycle.
I'm getting very muddled and I'm a beginner so any help with this would be great appreciated! Below is my code so far!
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace fra_walk
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
GamePadState pad1, oldpad1;
Rectangle srcRect;
struct Rect
{
public Rectangle destRect;
public Rectangle frame;
public Point velocity;
}
Rect destRect;
struct Wright
{
public Texture2D txr;
public Rectangle frame;
}
Wright walkright;
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
graphics.PreferredBackBufferWidth = 800;
graphics.PreferredBackBufferHeight = 600;
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
destRect.velocity = new Point(0, 0);
destRect.frame = new Rectangle(400, 400, 83, 170);
srcRect = new Rectangle(0, 0, 64, 170);
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
walkright.txr = Content.Load<Texture2D>("walk right");
// TODO: use this.Content to load your game content here
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
GamePadState pad1 = GamePad.GetState(PlayerIndex.One);
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
srcRect.X += srcRect.Width;
// if ((pad1.ThumbSticks.Left.X == 1.0f)
// && (oldpad1.ThumbSticks.Left.X == 1.0f))
// {
// srcRect.X += destRect.frame.Width;
// }
oldpad1 = pad1;
// TODO: Add your update logic here
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
spriteBatch.Begin();
spriteBatch.Draw(walkright.txr, destRect.frame, srcRect, Color.White);
spriteBatch.End();
// TODO: Add your drawing code here
base.Draw(gameTime);
}
}
}
An easy way to do what you're wanting would probably be to implement a counter.
Add something like public double animCounter = 0 to the top of your code.
Then around the srcRect.X += srcRect.Width; line add something to the effect of:
if (animCounter > 0)
{
animCounter -= gameTime.ElapsedGameTime.TotalSeconds;
}
else
{
srcRect.X += srcRect.Width;
animCounter = 0.5f;
}
Again, this is the easy way to do what you're wanting to do, but not necessarily the best. For one, += srcRect.Width will quickly exceed the width of your sprite sheet, so you'd need to check for that and correct it. As itsme86 suggested, you should search Google for some tutorials.
This one isn't a bad start:
http://msdn.microsoft.com/en-us/library/bb203866.aspx
I have just started making a game that is going to be somewhat like space invaders.
I'm a complete novice when it comes to programming and have little experience (I'm only attempting this as I need to have a software design project due at the end of next week).
Anyways, I have been following a tutorial on how to fire bullets. and it doesn't seem to be working. I have copied almost every aspect of this tutorial except for the 'velocity' variable in the 'bullets' class (which I don't think I need as I'm only using side to side movement not forward/back).
This is the code below. Thanks in advance. :)
Main
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace Software_Design_Major_Project
{
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
Texture2D ship; // Declaring the sprite
Vector2 shipposition = Vector2.Zero;
List<bullets> bullets = new List<bullets>();
KeyboardState pastkey;
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
graphics.PreferredBackBufferWidth = 600;
}
protected override void Initialize()
{
base.Initialize();
}
protected override void LoadContent()
{
spriteBatch = new SpriteBatch(GraphicsDevice);
ship = Content.Load<Texture2D>("ship"); // Loads the ship into the memory.
shipposition = new Vector2((graphics.GraphicsDevice.Viewport.Width / 2) -
(ship.Width / 2), 420);
}
protected override void UnloadContent()
{
}
protected override void Update(GameTime gameTime)
{
if (Keyboard.GetState(PlayerIndex.One).IsKeyDown(Keys.Left) && shipposition.X
>= 0)
{
shipposition.X -= 6;
}
if(Keyboard.GetState(PlayerIndex.One).IsKeyDown(Keys.Right) && shipposition.X <
((graphics.GraphicsDevice.Viewport.Width) - (ship.Width)))
{
shipposition.X += 6;
}
if (Keyboard.GetState().IsKeyDown(Keys.Space) && pastkey.IsKeyUp(Keys.Space))
{
shoot();
}
pastkey = Keyboard.GetState();
updatebullets();
base.Update(gameTime);
}
public void updatebullets()
{
foreach(bullets bullet in bullets)
{
if (Vector2.Distance(bullet.position, shipposition) < 0)
bullet.isvisible = false;
}
for (int i = 0; i < bullets.Count; i++)
{
if (!bullets[i].isvisible)
bullets.RemoveAt(i);
i--;
}
}
public void shoot()
{
bullets newbullet = new bullets(Content.Load<Texture2D>("bullet"));
newbullet.position = shipposition;
newbullet.isvisible = true;
if (bullets.Count < 20)
bullets.Add(newbullet);
}
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend);
spriteBatch.Draw(ship, shipposition, Color.White);
spriteBatch.End();
foreach (bullets bullet in bullets)
bullet.Draw(spriteBatch);
base.Draw(gameTime);
}
}
}
Bullets
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
namespace Software_Design_Major_Project
{
class bullets // A new class needs to be created to allow for bullets.
{
public Texture2D texture;
public Vector2 position;
public Vector2 origin;
public bool isvisible;
public bullets(Texture2D newtexture)
{
texture = newtexture;
isvisible = false;
}
public void Draw(SpriteBatch spritebatch)
{
spritebatch.Draw(texture, position, null, Color.White, 0f, origin, 1f,
SpriteEffects.None, 0);
}
}
}
P.S. Sorry for the long post.
I don't see any code that changes your bullets position, Your going to need a velocity variable, and update the position based on the velocity each frame.
And you could get the angle from a = Math.Atan(Y,X)
Looks like you probably removed the part that calculates position, as you thought you didn't need the velocity stuff. I suggest you try adding it back to see if it works, and then removing parts you don't need.
Surprised nobody spotted this sooner.
You're ending your SpriteBatch before the bullets have been drawn.
Calls to SpriteBatch.Draw must occur between the Begin and End methods because of all the work that goes on behind the scenes to make drawing as fast as possible.
All you need to do is move spriteBatch.End() further down, like so:
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend);
spriteBatch.Draw(ship, shipposition, Color.White);
foreach (bullets bullet in bullets)
bullet.Draw(spriteBatch);
spriteBatch.End(); //Move to here instead
base.Draw(gameTime);
}
Extra Trivia:
Basically what goes on behind the scenes is that the sprite batch actually batches up the textures using the settings described by begin (yes, these can be changed) and then when end is called, it figures out which bits fall outside the screen and makes note not to draw them, it depth sorts the textures if told to and it does all sorts of other optimisations before drawing them to the back buffer and then finally when all drawing is over, the back buffer gets presented to the screen and the old one is taken and reused for the next draw call. It sounds like a lot of work, but with the way modern computers work, the optimisations tend to create a big improvement.
you could check this sample right here. I've coded this stuff a long time ago, I think in v2.0 of XNA, can't rembember now.
http://gozoomin.com/media/p/69699.aspx
The logic in there is quit simple :)
Starting making a 'classic' is always a good way to start.
Edit - You can get it here as well: http://www.sendspace.com/file/r4s4um
Edit2 - I just checked the code now, it's with some comments documenting most of things, probably you will get some stuff written in portuguese.
PS - Don't copy past the code! Try to learn the basics around the sample.
I have 2 sprites which when drawn together make up the correct image on the screen. Drawing them both at the same time is not an option.
Imagine this class:
class MyImage
{
Vector2 drawOffset; // this gets added before the image is drawn
Vector2 sourceRect; // this is where it is on the source texturepage
void Draw(Vector2 position)
{
position = position + drawOffset;
spriteBatch.Draw(sourceTexture, position, sourceRect, Color.White);
}
}
And this code calling into it:
MyImage a = new MyImage(); // assume they get initialised correctly
MyImage b = new MyImage(); // with different drawOffsets and sourceRects
a.Draw(position); // this composes the final
b.Draw(position); // screen image from the 2 source images
Now I'd like to add scale and rotation to the Draw() function, but am having real trouble getting the parameters to the SpriteBatch.Draw function correct. This would be the version which takes scale, rotation and an origin. I need the final composed image to scale and rotate correctly (around some arbitrary centre) but can't for the life of me work out how to manipulate the scale, rotation and origin parameters to make the 2 images appear to scale and rotate in concert. Has anyone done something like this before? Happy to mod the question based on feedback if anything's unclear. If images would help I can get them posted somewhere...
I've looked at rotation around point xna 2D but am still stumped.
Cheers,
Charlie.
Thanks so much for the answer below - using it I've managed to get the images rendering correctly. One other issue remains, which is that I seem to need to use a lot of spritebatch.Begin/End pairs (one per image render). I don't have a way to measure performance on this device yet and the framerate's not chugging so I guess it's not a problem.
Here's my code:
// gr is the graphic object:
// gr.position is the location of the image in the atlas
// gr.DrawOffset is the draw offset so the image is placed correctly in it's virtual box
// gr.pageIndex is the index into the texture/atlas array
// hw,hh are half the width/height of the image (it always rotates around it's centre in fact)
Matrix m = Matrix.CreateTranslation(-hw, -hh, 0) *
Matrix.CreateRotationZ(rotation) * // rotation : parameter
Matrix.CreateScale(scale) * // scale : parameter
Matrix.CreateTranslation(pos.X + hw, pos.Y + hh, 0); // pos : parameter!
spriteBatch.Begin(SpriteSortMode.Deferred, null, null, null, null, null, m);
spriteBatch.Draw(page[gr.pageIndex].texture, gr.DrawOffset, gr.position, color);
spriteBatch.End();
If you are going to work with the SpriteBatch.Draw to draw the textures I would suggest that you forgo trying to manipulate the origin, scale arguments to try an achieve this, simply I doubt it can be done this way. But you do have an alternative, you can manipulate the SpriteBatch Matrix.
Here is a quick and dirty example, note that the texture I used here is 128x96 so I hard coded the values for that image size. Do not look for any best practices in this code, I wrote it to try and show the concept as cleanly as possible.
using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
namespace WindowsGame1
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
private Texture2D _texture;
private MyImage _image1;
private MyImage _image2;
// Attributes of the composed sprite
private float _angle = 0.0f;
private Vector2 _position = new Vector2(100, 100);
private Vector2 _rotationPoint = new Vector2(96, 48);
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
_texture = Content.Load<Texture2D>("Gravitar");
// Create the two MyImage instances
_image1 = new MyImage(_texture, Vector2.Zero, Vector2.Zero);
_image2 = new MyImage(_texture, new Vector2(64, 0), new Vector2(64, 0));
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
float elapsedTime = (float)gameTime.ElapsedGameTime.TotalSeconds;
_angle += 0.5f * elapsedTime;
if (Mouse.GetState().LeftButton == ButtonState.Pressed)
{
_angle = 0.0f;
}
if (Keyboard.GetState().IsKeyDown(Keys.Left))
_position += new Vector2(-10, 0)*elapsedTime;
if (Keyboard.GetState().IsKeyDown(Keys.Right))
_position += new Vector2(10, 0) * elapsedTime;
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
// Setup the sprite batch matrix
// Notice that we first translate to the point or rotation
// then rotate and when we translate to the desired position we
// need to compensate for the first translation so that the texture
// appears at the correct location
Matrix m =
Matrix.CreateScale(1.5f)
* Matrix.CreateTranslation(-_rotationPoint.X, -_rotationPoint.Y, 0)
* Matrix.CreateRotationZ(_angle)
* Matrix.CreateTranslation(_position.X + _rotationPoint.X, _position.Y + _rotationPoint.Y, 0);
// Begin the SpriteBatch passing the matrix
spriteBatch.Begin(SpriteSortMode.Deferred, null, null, null, null, null, m);
_image1.Draw(spriteBatch);
_image2.Draw(spriteBatch);
spriteBatch.End();
base.Draw(gameTime);
}
class MyImage
{
Vector2 _drawOffset;
Vector2 _sourcePoint;
Texture2D _sourceTexture;
public MyImage(Texture2D sourceTexture, Vector2 sourcePoint, Vector2 drawOffset)
{
_drawOffset = drawOffset;
_sourcePoint = sourcePoint;
_sourceTexture = sourceTexture;
}
public void Draw(SpriteBatch spriteBatch)
{
spriteBatch.Draw(_sourceTexture, _drawOffset,
new Rectangle((int)_sourcePoint.X, (int)_sourcePoint.Y, 64, 96),
Color.White);
}
}
}
}