بســم الله الـرحمــن الرحيــم الدرس الثامن عشر أهلا بكم في الدرس الثامن عشر من سلسلة دروس تعلم الXna , في هذا الدرس سوف نتحدث عن موضوع مزج ألفا المضافة “Additive alpha blending”. المشكلة الرئيسة في نتيجة الدرس السابق هو أنه تم رسم صورة الإنفجار كما هي بالاصل في الصورة الأصلية. بمعنى أنه تم رسم الخلفية و الحدود السوداء للصورة فوق المحتويات الموجودة في الذاكرة الخلفية “backbuffer” لبطاقة الرسوميات. في هذا الدرس سوف نقوم بإصلاح هذه المشكلة من خلال تشغيل مزج ألفا المضافة قبل رسم الجزيئات. أولا سنتحدث قليلا عن الموضوع. في مزج ألفا نحن مهتمين بالحصول على لون جديد للبكسل، إعتمادا على اللونين التاليين: • اللون الأصلي SourceColor : اللون الجديد، اللون الناتج من الصورة التي يتم رسمها. • اللون الهدف DestinationColor : لون البكسل السابق الموجود في الذاكرة الخلفية و الذي سوف نقوم بالرسم فوقه. يتم مزج كلا من اللونين معا من أجل الحصول على اللون الجديد للبكسل. في ال Xna يتم ضرب كل من ال SourceColor و ال DestinationColor بمعامل:
device.RenderState.AlphaBlendEnable = true; device.RenderState.SourceBlend = Blend.One; device.RenderState.DestinationBlend = Blend.One;
spriteBatch.Begin(); DrawScenery(); DrawPlayers(); DrawText(); DrawRocket(); DrawSmoke(); spriteBatch.End(); spriteBatch.Begin(SpriteBlendMode.Additive, SpriteSortMode.Deferred, SaveStateMode.None); DrawExplosion(); spriteBatch.End();
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 + rand1); 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, TextureUsage.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(); ProcessKeyboard(); if (rocketFlying) { UpdateRocket(); CheckCollisions(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, rocketPosition.Y, 0); Matrix terrainMat = Matrix.Identity; Vector2 terrainCollisionPoint = TexturesCollide(rocketColorArray, rocketMat, foregroundColorArray, terrainMat); return terrainCollisionPoint; } private Vector2 CheckPlayersCollision() { Matrix rocketMat = Matrix.CreateTranslation(-42, -240, 0) * Matrix.CreateRotationZ(rocketAngle) * Matrix.CreateScale(rocketScaling) * Matrix.CreateTranslation(rocketPosition.X, rocketPosition.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.Height, 0) * Matrix.CreateScale(playerScaling) * Matrix.CreateTranslation(xPos, yPos, 0); Vector2 carriageCollisionPoint = TexturesCollide(carriageColorArray, carriageMat, rocketColorArray, rocketMat); if (carriageCollisionPoint.X > -1) { players[i].IsAlive = false; return carriageCollisionPoint; } Matrix cannonMat = Matrix.CreateTranslation(-11, -50, 0) * Matrix.CreateRotationZ(player.Angle) * Matrix.CreateScale(playerScaling) * Matrix.CreateTranslation(xPos + 20, yPos - 10, 0); Vector2 cannonCollisionPoint = TexturesCollide(cannonColorArray, cannonMat, 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, float maxAge, GameTime gameTime) { for (int i = 0; i < numberOfParticles; i++) AddExplosionParticle(explosionPos, size, maxAge, gameTime); } private void AddExplosionParticle(Vector2 explosionPos, float explosionSize, float maxAge, 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; particle.Accelaration = 3.0f * particle.Direction; particleList.Add(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, player.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 Vector2(20, 20), player.Color); spriteBatch.DrawString(font, "Cannon power: " + player.Power.ToString(), new Vector2(20, 45), player.Color); } private void DrawRocket() { if (rocketFlying) spriteBatch.Draw(rocketTexture, rocketPosition, null, players[currentPlayer].Color, 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); } } } }