using System;
 using System.Collections.Generic;
 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.Net;
 using Microsoft.Xna.Framework.Storage;
 
 namespace XNAtutorial
 {
     public struct ParticleData
     {
         public float BirthTime;
         public float MaxAge;
         public Vector2 OrginalPosition;
         public Vector2 Accelaration;
         public Vector2 Direction;
         public Vector2 Position;
         public float Scaling;
         public Color ModColor;
     }
 
     public struct PlayerData
     {
         public Vector2 Position;
         public bool IsAlive;
         public Color Color;
         public float Angle;
         public float Power;
     }
 
     public class Game1 : Microsoft.Xna.Framework.Game
     {
         GraphicsDeviceManager graphics;
         SpriteBatch spriteBatch;
         GraphicsDevice device;
 
         int screenWidth;
         int screenHeight;
 
         Texture2D backgroundTexture;
         Texture2D foregroundTexture;
         Texture2D carriageTexture;
         Texture2D cannonTexture;
         Texture2D rocketTexture;
         Texture2D smokeTexture;
         Texture2D groundTexture;
         Texture2D explosionTexture;
         SpriteFont font;
 
         PlayerData players;
         int numberOfPlayers = 4;
         float playerScaling;
         int currentPlayer = 0;
 
         bool rocketFlying = false;
         Vector2 rocketPosition;        
         Vector2 rocketDirection;
         float rocketAngle;
         float rocketScaling = 0.1f;
 
 
        List particleList = new List ();
        List smokeList = new List ();        Random randomizer = new Random()
;
        int terrainContour;
 
        Color rocketColorArray;
        Color foregroundColorArray;
        Color carriageColorArray;
        Color cannonColorArray;
 
        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }
 
        protected override void Initialize()
        {
            graphics.PreferredBackBufferWidth = 500;
            graphics.PreferredBackBufferHeight = 500;
            graphics.IsFullScreen = false;
            graphics.ApplyChanges();
            Window.Title = "Riemer's 2D XNA Tutorial";
 
            base.Initialize();
        }
 
        protected override void LoadContent()
        {
            device = graphics.GraphicsDevice;
            spriteBatch = new SpriteBatch(device);
 
            screenWidth = device.PresentationParameters.BackBufferWidth;
            screenHeight = device.PresentationParameters.BackBufferHeight;
 
 
            backgroundTexture = Content.Load ("background");
            carriageTexture = Content.Load ("carriage");
            cannonTexture = Content.Load ("cannon");
            rocketTexture = Content.Load ("rocket");
            smokeTexture = Content.Load ("smoke");
            groundTexture = Content.Load ("ground");
            font = Content.Load ("myFont");
            explosionTexture = Content.Load ("explosion");                        
            playerScaling = 40.0f / (float)carriageTexture.Width;
            GenerateTerrainContour();            
            SetUpPlayers();
            FlattenTerrainBelowPlayers();
            CreateForeground();
 
            rocketColorArray = TextureTo2DArray(rocketTexture);
            carriageColorArray = TextureTo2DArray(carriageTexture);
            cannonColorArray = TextureTo2DArray(cannonTexture);
        }
 
        private void SetUpPlayers()
        {
            Color playerColors = new Color[10];
            playerColors[0] = Color.Red;
            playerColors[1] = Color.Green;
            playerColors[2] = Color.Blue;
            playerColors[3] = Color.Purple;
            playerColors[4] = Color.Orange;
            playerColors[5] = Color.Indigo;
            playerColors[6] = Color.Yellow;
            playerColors[7] = Color.SaddleBrown;
            playerColors[8] = Color.Tomato;
            playerColors[9] = Color.Turquoise;
 
            players = new PlayerData[numberOfPlayers];
            for (int i = 0; i < numberOfPlayers; i++)
            {
                players[i].IsAlive = true;
                players[i].Color = playerColors[i];
                players[i].Angle = MathHelper.ToRadians(90);
                players[i].Power = 100;
                players[i].Position = new Vector2();
                players[i].Position.X = screenWidth / (numberOfPlayers + 1) * (i + 1);
                players[i].Position.Y = terrainContour[(int)players[i].Position.X];
            }
        }
 
        private void GenerateTerrainContour()
        {
            terrainContour = new int[screenWidth];
 
            double rand1 = randomizer.NextDouble() + 1;
            double rand2 = randomizer.NextDouble() + 2;
            double rand3 = randomizer.NextDouble() + 3;
 
            float offset = screenHeight / 2; ;
            float peakheight = 100;
            float flatness = 70;
 
            for (int x = 0; x < screenWidth; x++)
            {
                double height = peakheight / rand1 * Math.Sin((float)x / flatness * rand1 + ran
d1);
                height += peakheight / rand2 * Math.Sin((float)x / flatness * rand2 + rand2);
                height += peakheight / rand3 * Math.Sin((float)x / flatness * rand3 + rand3);
                height += offset;
                terrainContour[x] = (int)height;
            }
        }
 
        private void FlattenTerrainBelowPlayers()
        {
            foreach (PlayerData player in players)
                if (player.IsAlive)
                    for (int x = 0; x < 40; x++)
                        terrainContour[(int)player.Position.X + x] = terrainContour[(int)player
.Position.X];
        }
 
        private void CreateForeground()
        {
            Color groundColors = TextureTo2DArray(groundTexture);
            Color foregroundColors = new Color[screenWidth * screenHeight];
 
            for (int x = 0; x < screenWidth; x++)
            {
                for (int y = 0; y < screenHeight; y++)
                {
                    if (y > terrainContour[x])
                        foregroundColors[x + y * screenWidth] = groundColors[x % groundTexture.
Width, y % groundTexture.Height];
                    else                        
                        foregroundColors[x + y * screenWidth] = Color.TransparentBlack;
                }
            }
 
            foregroundTexture = new Texture2D(device, screenWidth, screenHeight, 1, TextureUsag
e.None, SurfaceFormat.Color);
            foregroundTexture.SetData(foregroundColors);
            foregroundColorArray = TextureTo2DArray(foregroundTexture);
        }
 
        private Color TextureTo2DArray(Texture2D texture)
        {
            Color colors1D = new Color[texture.Width * texture.Height];
            texture.GetData(colors1D);
 
            Color colors2D = new Color[texture.Width, texture.Height];
            for (int x = 0; x < texture.Width; x++)
                for (int y = 0; y < texture.Height; y++)
                    colors2D[x, y] = colors1D[x + y * texture.Width];
 
            return colors2D;
        }
 
        protected override void UnloadContent()
        {
        }
 
        protected override void Update(GameTime gameTime)
        {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();
 
            if ((!rocketFlying) && (particleList.Count == 0))
                ProcessKeyboard();                
 
            if (rocketFlying)
            {
                UpdateRocket();
                CheckCollisions(gameTime);
            }
 
            if (particleList.Count > 0)
                UpdateParticles(gameTime);
 
            base.Update(gameTime);
        }
 
        private void ProcessKeyboard()
        {
            KeyboardState keybState = Keyboard.GetState();
            if (keybState.IsKeyDown(Keys.Left))
                players[currentPlayer].Angle -= 0.01f;
            if (keybState.IsKeyDown(Keys.Right))
                players[currentPlayer].Angle += 0.01f;
 
            if (players[currentPlayer].Angle > MathHelper.PiOver2)
                players[currentPlayer].Angle = -MathHelper.PiOver2;
            if (players[currentPlayer].Angle < -MathHelper.PiOver2)
                players[currentPlayer].Angle = MathHelper.PiOver2;
 
            if (keybState.IsKeyDown(Keys.Down))
                players[currentPlayer].Power -= 1;
            if (keybState.IsKeyDown(Keys.Up))
                players[currentPlayer].Power += 1;
            if (keybState.IsKeyDown(Keys.PageDown))
                players[currentPlayer].Power -= 20;
            if (keybState.IsKeyDown(Keys.PageUp))
                players[currentPlayer].Power += 20;
 
            if (players[currentPlayer].Power > 1000)
                players[currentPlayer].Power = 1000;
            if (players[currentPlayer].Power < 0)
                players[currentPlayer].Power = 0;
 
            if (keybState.IsKeyDown(Keys.Enter) || keybState.IsKeyDown(Keys.Space))
            {
                rocketFlying = true;
                rocketPosition = players[currentPlayer].Position;
                rocketPosition.X += 20;
                rocketPosition.Y -= 10;
                rocketAngle = players[currentPlayer].Angle;
                Vector2 up = new Vector2(0, -1);
                Matrix rotMatrix = Matrix.CreateRotationZ(rocketAngle);
                rocketDirection = Vector2.Transform(up, rotMatrix);
                rocketDirection *= players[currentPlayer].Power / 50.0f;
            }
        }
 
        private void UpdateRocket()
        {
            if (rocketFlying)
            {
                Vector2 gravity = new Vector2(0, 1);
                rocketDirection += gravity / 10.0f;
                rocketPosition += rocketDirection;
                rocketAngle = (float)Math.Atan2(rocketDirection.X, -rocketDirection.Y);
 
                for (int i = 0; i < 5; i++)
                {
                    Vector2 smokePos = rocketPosition;
                    smokePos.X += randomizer.Next(10) - 5;
                    smokePos.Y += randomizer.Next(10) - 5;
                    smokeList.Add(smokePos);
                }
            }
        }
 
        private Vector2 TexturesCollide(Color tex1, Matrix mat1, Color tex2, Matrix mat2)
        {
            Matrix mat1to2 = mat1 * Matrix.Invert(mat2);
 
            int width1 = tex1.GetLength(0);
            int height1 = tex1.GetLength(1);
            int width2 = tex2.GetLength(0);
            int height2 = tex2.GetLength(1);
 
            for (int x1 = 0; x1 < width1; x1++)
            {
                for (int y1 = 0; y1 < height1; y1++)
                {
                    Vector2 pos1 = new Vector2(x1, y1);
                    Vector2 pos2 = Vector2.Transform(pos1, mat1to2);
 
                    int x2 = (int)pos2.X;
                    int y2 = (int)pos2.Y;
                    if ((x2 >= 0) && (x2 < width2))
                    {
                        if ((y2 >= 0) && (y2 < height2))
                        {
                            if (tex1[x1, y1].A > 0)
                            {
                                if (tex2[x2, y2].A > 0)
                                {
                                    Vector2 screenPos = Vector2.Transform(pos1, mat1);
                                    return screenPos;
                                }
                            }
                        }
                    }
                }
            }
 
            return new Vector2(-1, -1);
        }
 
        private Vector2 CheckTerrainCollision()
        {
            Matrix rocketMat = Matrix.CreateTranslation(-42, -240, 0) * Matrix.CreateRotationZ(
rocketAngle) * Matrix.CreateScale(rocketScaling) * Matrix.CreateTranslation(rocketPosition.X, r
ocketPosition.Y, 0);
            Matrix terrainMat = Matrix.Identity;
            Vector2 terrainCollisionPoint = TexturesCollide(rocketColorArray, rocketMat, foregr
oundColorArray, terrainMat);
            return terrainCollisionPoint;
        }
 
        private Vector2 CheckPlayersCollision()
        {
            Matrix rocketMat = Matrix.CreateTranslation(-42, -240, 0) * Matrix.CreateRotationZ(
rocketAngle) * Matrix.CreateScale(rocketScaling) * Matrix.CreateTranslation(rocketPosition.X, r
ocketPosition.Y, 0);
            for (int i = 0; i < numberOfPlayers; i++)
            {
                PlayerData player = players[i];
                if (player.IsAlive)
                {
                    if (i != currentPlayer)
                    {
                        int xPos = (int)player.Position.X;
                        int yPos = (int)player.Position.Y;
 
                        Matrix carriageMat = Matrix.CreateTranslation(0, -carriageTexture.Heigh
t, 0) * Matrix.CreateScale(playerScaling) * Matrix.CreateTranslation(xPos, yPos, 0);
                        Vector2 carriageCollisionPoint = TexturesCollide(carriageColorArray, ca
rriageMat, rocketColorArray, rocketMat);
                        if (carriageCollisionPoint.X > -1)
                        {
                            players[i].IsAlive = false;
                            return carriageCollisionPoint;
                        }
 
                        Matrix cannonMat = Matrix.CreateTranslation(-11, -50, 0) * Matrix.Creat
eRotationZ(player.Angle) * Matrix.CreateScale(playerScaling) * Matrix.CreateTranslation(xPos + 
20, yPos - 10, 0);
                        Vector2 cannonCollisionPoint = TexturesCollide(cannonColorArray, cannon
Mat, rocketColorArray, rocketMat);
                        if (cannonCollisionPoint.X > -1)
                        {
                            players[i].IsAlive = false;
                            return cannonCollisionPoint;
                        }
                    }
                }
            }
            return new Vector2(-1, -1);
        }
 
        private bool CheckOutOfScreen()
        {
            bool rocketOutOfScreen = rocketPosition.Y > screenHeight;
            rocketOutOfScreen |= rocketPosition.X < 0;
            rocketOutOfScreen |= rocketPosition.X > screenWidth;
 
            return rocketOutOfScreen;
        }
 
        private void CheckCollisions(GameTime gameTime)
        {
            Vector2 terrainCollisionPoint = CheckTerrainCollision();
            Vector2 playerCollisionPoint = CheckPlayersCollision();
            bool rocketOutOfScreen = CheckOutOfScreen();
 
            if (playerCollisionPoint.X > -1)
            {
                rocketFlying = false;
 
                smokeList = new List ();                NextPlayer();
                AddExplosion(playerCollisionPoint, 10, 80.0f, 2000.0f, gameTime);
            }
 
            if (terrainCollisionPoint.X > -1)
            {
                rocketFlying = false;                
 
                smokeList = new List ();                NextPlayer();
                AddExplosion(terrainCollisionPoint, 4, 30.0f, 1000.0f, gameTime);
            }
 
            if (rocketOutOfScreen)
            {
                rocketFlying = false;
 
                smokeList = new List ();                NextPlayer();                
            }
        }
 
        private void NextPlayer()
        {
            currentPlayer = currentPlayer + 1;
            currentPlayer = currentPlayer % numberOfPlayers;
            while (!players[currentPlayer].IsAlive)
            {
                currentPlayer = ++currentPlayer % numberOfPlayers;
            }
        }
 
        private void AddExplosion(Vector2 explosionPos, int numberOfParticles, float size, floa
t maxAge, GameTime gameTime)
        {
            for (int i = 0; i < numberOfParticles; i++)
                AddExplosionParticle(explosionPos, size, maxAge, gameTime);
        }
 
        private void AddExplosionParticle(Vector2 explosionPos, float explosionSize, float maxA
ge, GameTime gameTime)
        {
            ParticleData particle = new ParticleData();
 
            particle.OrginalPosition = explosionPos;
            particle.Position = particle.OrginalPosition;
 
            particle.BirthTime = (float)gameTime.TotalGameTime.TotalMilliseconds;
            particle.MaxAge = maxAge;
            particle.Scaling = 0.25f;
            particle.ModColor = Color.White;
 
            float particleDistance = (float)randomizer.NextDouble() * explosionSize;
            Vector2 displacement = new Vector2(particleDistance, 0);
            float angle = MathHelper.ToRadians(randomizer.Next(360));
            displacement = Vector2.Transform(displacement, Matrix.CreateRotationZ(angle));
 
 
             particle.Direction = displacement * 2.0f;
             particle.Accelaration = -particle.Direction;            
 
             particleList.Add(particle);
         }
 
         private void UpdateParticles(GameTime gameTime)
         {
             float now = (float)gameTime.TotalGameTime.TotalMilliseconds;
             for (int i = particleList.Count - 1; i >= 0; i--)
             {
                 ParticleData particle = particleList[i];
                 float timeAlive = now - particle.BirthTime;
 
                 if (timeAlive > particle.MaxAge)
                 {
                     particleList.RemoveAt(i);
                 }
                 else
                 {
                     float relAge = timeAlive / particle.MaxAge;
                     particle.Position = 0.5f * particle.Accelaration * relAge * relAge + parti
cle.Direction * relAge + particle.OrginalPosition;
 
                     float invAge = 1.0f - relAge;
                     particle.ModColor = new Color(new Vector4(invAge, invAge, invAge, invAge))
;
 
                     Vector2 positionFromCenter = particle.Position - particle.OrginalPosition;
                     float distance = positionFromCenter.Length();
                     particle.Scaling = (50.0f + distance) / 200.0f;
 
                     particleList[i] = particle;
                 }
             }
         }
 
         protected override void Draw(GameTime gameTime)
         {
             graphics.GraphicsDevice.Clear(Color.CornflowerBlue);
 
             spriteBatch.Begin();
             DrawScenery();
             DrawPlayers();
             DrawText();
             DrawRocket();
             DrawSmoke();            
             spriteBatch.End();                        
 
             spriteBatch.Begin(SpriteBlendMode.Additive, SpriteSortMode.Deferred, SaveStateMode
.None);
             DrawExplosion();
             spriteBatch.End();
 
             base.Draw(gameTime);
         }
 
         private void DrawScenery()
         {
             Rectangle screenRectangle = new Rectangle(0, 0, screenWidth, screenHeight);
             spriteBatch.Draw(backgroundTexture, screenRectangle, Color.White);
             spriteBatch.Draw(foregroundTexture, screenRectangle, Color.White);
         }
 
         private void DrawPlayers()
         {
             foreach (PlayerData player in players)
             {
                 if (player.IsAlive)
                 {
                     int xPos = (int)player.Position.X;
                     int yPos = (int)player.Position.Y;
                     Vector2 cannonOrigin = new Vector2(11, 50);
 
                     spriteBatch.Draw(cannonTexture, new Vector2(xPos + 20, yPos - 10), null, p
layer.Color, player.Angle, cannonOrigin, playerScaling, SpriteEffects.None, 1);
                     spriteBatch.Draw(carriageTexture, player.Position, null, player.Color, 0, 
new Vector2(0, carriageTexture.Height), playerScaling, SpriteEffects.None, 0);
                 }
             }
         }
 
         private void DrawText()
         {
             PlayerData player = players[currentPlayer];
             int currentAngle = (int)MathHelper.ToDegrees(player.Angle);
             spriteBatch.DrawString(font, "Cannon angle: " + currentAngle.ToString(), new Vecto
r2(20, 20), player.Color);
             spriteBatch.DrawString(font, "Cannon power: " + player.Power.ToString(), new Vecto
r2(20, 45), player.Color);
         }
 
         private void DrawRocket()
         {
             if (rocketFlying)
                 spriteBatch.Draw(rocketTexture, rocketPosition, null, players[currentPlayer].C
olor, rocketAngle, new Vector2(42, 240), rocketScaling, SpriteEffects.None, 1);
         }
 
         private void DrawSmoke()
         {
             foreach (Vector2 smokePos in smokeList)
                 spriteBatch.Draw(smokeTexture, smokePos, null, Color.White, 0, new Vector2(40,
 35), 0.2f, SpriteEffects.None, 1);
         }
 
         private void DrawExplosion()
         {
             for (int i = 0; i < particleList.Count; i++)
             {
                 ParticleData particle = particleList[i];
                 spriteBatch.Draw(explosionTexture, particle.Position, null, particle.ModColor,
 i, new Vector2(256, 256), particle.Scaling, SpriteEffects.None, 1);
             }
         }
     }
 }