使用BasicEffect
原文地址http://msdn.microsoft.com/zh-cn/library/bb203926(v=xnagamestudio.10).aspx
这个案例展示了如何创建并初始化一个实例BasicEffect,初始化一个顶点缓冲,可以提供BasicEffect、应用效果和呈现几何。
注意 这里描述的步骤适用于创建的效果BasicEffect类。 相比之下，Effect类 提供了用户希望编写的自定义效果，有关更详细的信息，请参考 如何:创建和应用的自定制效果。
使用BasicEffect
1、使用BasicEffect类需要一组世界、视图和投影矩阵，一个顶点缓冲， 一个顶点声明和一个BasicEffect类的实例。在游戏开始的时候声明这些变量。
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Matrix worldMatrix; Matrix viewMatrix; Matrix projectionMatrix; VertexPositionNormalTexture[] cubeVertices; VertexDeclaration basicEffectVertexDeclaration; VertexBuffer vertexBuffer; BasicEffect basicEffect; |
2、初始化世界、视图和投影矩阵。在这个示例中，创建一个世界矩阵 沿x轴和y轴几何旋转22.5度。视图矩阵是一个矩阵的摄像机，看位置从(0,0,5)指向原点。投影矩阵是一个透视投影矩阵基于视野,指定一个45度的视野,一个宽高比等于客户的窗口,和一组远近的飞机。
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float tilt = MathHelper.ToRadians( 22.5f ); // 22.5 degree angle // Use the world matrix to tilt the cube along x and y axes. worldMatrix = Matrix.CreateRotationX( tilt ) * Matrix.CreateRotationY( tilt ); viewMatrix = Matrix.CreateLookAt( new Vector3( 0, 0, 5 ), Vector3.Zero, Vector3.Up ); projectionMatrix = Matrix.CreatePerspectiveFieldOfView( MathHelper.ToRadians( 45 ), // 45 degree angle (float)graphics.GraphicsDevice.Viewport.Width / (float)graphics.GraphicsDevice.Viewport.Height, 1.0f, 100.0f ); |
3、初始化BasicEffect 所需要的值
| basicEffect = new BasicEffect( graphics.GraphicsDevice, null ); basicEffect.Alpha = 1.0f; basicEffect.DiffuseColor = new Vector3( 1.0f, 0.0f, 1.0f ); basicEffect.SpecularColor = new Vector3( 0.25f, 0.25f, 0.25f ); basicEffect.SpecularPower = 5.0f; basicEffect.AmbientLightColor = new Vector3( 0.75f, 0.75f, 0.75f ); basicEffect.DirectionalLight0.Enabled = true; basicEffect.DirectionalLight0.DiffuseColor = Vector3.One; basicEffect.DirectionalLight0.Direction = Vector3.Normalize( new Vector3( 1.0f, -1.0f, -1.0f ) ); basicEffect.DirectionalLight0.SpecularColor = Vector3.One; basicEffect.DirectionalLight1.Enabled = true; basicEffect.DirectionalLight1.DiffuseColor = new Vector3( 0.5f, 0.5f, 0.5f ); basicEffect.DirectionalLight1.Direction = Vector3.Normalize( new Vector3( -1.0f, -1.0f, 1.0f ) ); basicEffect.DirectionalLight1.SpecularColor = new Vector3( 0.5f, 0.5f, 0.5f ); basicEffect.LightingEnabled = true; basicEffect.World = worldMatrix; basicEffect.View = viewMatrix; basicEffect.Projection = projectionMatrix; |
4、 BasicEffect可以使用顶点类型,选择适当的选项你将使效果。
- 如果照明被启用,顶点必须有一个正常的。
- 如果顶点颜色被启用,顶点必须有颜色。
- 如果变形被启用,顶点必须有一个纹理坐标。
下面的代码显示了一个立方体的顶点上创建的类型VertexPositionNormalTexture。
| cubeVertices = new VertexPositionNormalTexture[36]; Vector3 topLeftFront = new Vector3( -1.0f, 1.0f, 1.0f ); Vector3 bottomLeftFront = new Vector3( -1.0f, -1.0f, 1.0f ); Vector3 topRightFront = new Vector3( 1.0f, 1.0f, 1.0f ); Vector3 bottomRightFront = new Vector3( 1.0f, -1.0f, 1.0f ); Vector3 topLeftBack = new Vector3( -1.0f, 1.0f, -1.0f ); Vector3 topRightBack = new Vector3( 1.0f, 1.0f, -1.0f ); Vector3 bottomLeftBack = new Vector3( -1.0f, -1.0f, -1.0f ); Vector3 bottomRightBack = new Vector3( 1.0f, -1.0f, -1.0f ); Vector2 textureTopLeft = new Vector2( 0.0f, 0.0f ); Vector2 textureTopRight = new Vector2( 1.0f, 0.0f ); Vector2 textureBottomLeft = new Vector2( 0.0f, 1.0f ); Vector2 textureBottomRight = new Vector2( 1.0f, 1.0f ); Vector3 frontNormal = new Vector3( 0.0f, 0.0f, 1.0f ); Vector3 backNormal = new Vector3( 0.0f, 0.0f, -1.0f ); Vector3 topNormal = new Vector3( 0.0f, 1.0f, 0.0f ); Vector3 bottomNormal = new Vector3( 0.0f, -1.0f, 0.0f ); Vector3 leftNormal = new Vector3( -1.0f, 0.0f, 0.0f ); Vector3 rightNormal = new Vector3( 1.0f, 0.0f, 0.0f ); // Front face. cubeVertices[0] = new VertexPositionNormalTexture( topLeftFront, frontNormal, textureTopLeft ); cubeVertices[1] = new VertexPositionNormalTexture( bottomLeftFront, frontNormal, textureBottomLeft ); cubeVertices[2] = new VertexPositionNormalTexture( topRightFront, frontNormal, textureTopRight ); cubeVertices[3] = new VertexPositionNormalTexture( bottomLeftFront, frontNormal, textureBottomLeft ); cubeVertices[4] = new VertexPositionNormalTexture( bottomRightFront, frontNormal, textureBottomRight ); cubeVertices[5] = new VertexPositionNormalTexture( topRightFront, frontNormal, textureTopRight ); // Back face. cubeVertices[6] = new VertexPositionNormalTexture( topLeftBack, backNormal, textureTopRight ); cubeVertices[7] = new VertexPositionNormalTexture( topRightBack, backNormal, textureTopLeft ); cubeVertices[8] = new VertexPositionNormalTexture( bottomLeftBack, backNormal, textureBottomRight ); cubeVertices[9] = new VertexPositionNormalTexture( bottomLeftBack, backNormal, textureBottomRight ); cubeVertices[10] = new VertexPositionNormalTexture( topRightBack, backNormal, textureTopLeft ); cubeVertices[11] = new VertexPositionNormalTexture( bottomRightBack, backNormal, textureBottomLeft ); // Top face. cubeVertices[12] = new VertexPositionNormalTexture( topLeftFront, topNormal, textureBottomLeft ); cubeVertices[13] = new VertexPositionNormalTexture( topRightBack, topNormal, textureTopRight ); cubeVertices[14] = new VertexPositionNormalTexture( topLeftBack, topNormal, textureTopLeft ); cubeVertices[15] = new VertexPositionNormalTexture( topLeftFront, topNormal, textureBottomLeft ); cubeVertices[16] = new VertexPositionNormalTexture( topRightFront, topNormal, textureBottomRight ); cubeVertices[17] = new VertexPositionNormalTexture( topRightBack, topNormal, textureTopRight ); // Bottom face. cubeVertices[18] = new VertexPositionNormalTexture( bottomLeftFront, bottomNormal, textureTopLeft ); cubeVertices[19] = new VertexPositionNormalTexture( bottomLeftBack, bottomNormal, textureBottomLeft ); cubeVertices[20] = new VertexPositionNormalTexture( bottomRightBack, bottomNormal, textureBottomRight ); cubeVertices[21] = new VertexPositionNormalTexture( bottomLeftFront, bottomNormal, textureTopLeft ); cubeVertices[22] = new VertexPositionNormalTexture( bottomRightBack, bottomNormal, textureBottomRight ); cubeVertices[23] = new VertexPositionNormalTexture( bottomRightFront, bottomNormal, textureTopRight ); // Left face. cubeVertices[24] = new VertexPositionNormalTexture( topLeftFront, leftNormal, textureTopRight ); cubeVertices[25] = new VertexPositionNormalTexture( bottomLeftBack, leftNormal, textureBottomLeft ); cubeVertices[26] = new VertexPositionNormalTexture( bottomLeftFront, leftNormal, textureBottomRight ); cubeVertices[27] = new VertexPositionNormalTexture( topLeftBack, leftNormal, textureTopLeft ); cubeVertices[28] = new VertexPositionNormalTexture( bottomLeftBack, leftNormal, textureBottomLeft ); cubeVertices[29] = new VertexPositionNormalTexture( topLeftFront, leftNormal, textureTopRight ); // Right face. cubeVertices[30] = new VertexPositionNormalTexture( topRightFront, rightNormal, textureTopLeft ); cubeVertices[31] = new VertexPositionNormalTexture( bottomRightFront, rightNormal, textureBottomLeft ); cubeVertices[32] = new VertexPositionNormalTexture( bottomRightBack, rightNormal, textureBottomRight ); cubeVertices[33] = new VertexPositionNormalTexture( topRightBack, rightNormal, textureTopRight ); cubeVertices[34] = new VertexPositionNormalTexture( topRightFront, rightNormal, textureTopLeft ); cubeVertices[35] = new VertexPositionNormalTexture( bottomRightBack, rightNormal, textureBottomRight ); vertexBuffer = new VertexBuffer( graphics.GraphicsDevice, VertexPositionNormalTexture.SizeInBytes * cubeVertices.Length, ResourceUsage.None, ResourceManagementMode.Automatic ); vertexBuffer.SetData<VertexPositionNormalTexture>( cubeVertices ); |
5、创建一个顶点声明类型VertexPositionNormalTexture. This vertex declaration will be used in the render loop in the next step
| basicEffectVertexDeclaration = new VertexDeclaration( graphics.GraphicsDevice, VertexPositionNormalTexture.VertexElements ); |
6、Call the Effect.Begin to begin applying the BasicEffect. Draw the desired geometry between calls to EffectPass.Begin and EffectPass.End. Call Effect.End to stop application of the technique.
| graphics.GraphicsDevice.VertexDeclaration = basicEffectVertexDeclaration; graphics.GraphicsDevice.Vertices[0].SetSource( vertexBuffer, 0, VertexPositionNormalTexture.SizeInBytes ); // This code would go between a device // BeginScene-EndScene block. basicEffect.Begin(); foreach (EffectPass pass in basicEffect.CurrentTechnique.Passes) { pass.Begin(); graphics.GraphicsDevice.DrawPrimitives( PrimitiveType.TriangleList, 0, 12 ); pass.End(); } basicEffect.End(); |
完整的例子
| using System; using System.Collections.Generic; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Storage; using Microsoft.Xna.Framework.Content; public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; ContentManager content; Matrix worldMatrix; Matrix viewMatrix; Matrix projectionMatrix; VertexPositionNormalTexture[] cubeVertices; VertexDeclaration basicEffectVertexDeclaration; VertexBuffer vertexBuffer; BasicEffect basicEffect; public Game1() { graphics = new GraphicsDeviceManager( this ); content = new ContentManager( Services ); } protected override void Initialize() { base.Initialize(); } protected override void LoadGraphicsContent( bool loadAllContent ) { InitializeTransform(); if (loadAllContent) { InitializeEffect(); InitializeCube(); } } private void InitializeTransform() { float tilt = MathHelper.ToRadians( 22.5f ); // 22.5 degree angle // Use the world matrix to tilt the cube along x and y axes. worldMatrix = Matrix.CreateRotationX( tilt ) * Matrix.CreateRotationY( tilt ); viewMatrix = Matrix.CreateLookAt( new Vector3( 0, 0, 5 ), Vector3.Zero, Vector3.Up ); projectionMatrix = Matrix.CreatePerspectiveFieldOfView( MathHelper.ToRadians( 45 ), // 45 degree angle (float)graphics.GraphicsDevice.Viewport.Width / (float)graphics.GraphicsDevice.Viewport.Height, 1.0f, 100.0f ); } private void InitializeEffect() { basicEffectVertexDeclaration = new VertexDeclaration( graphics.GraphicsDevice, VertexPositionNormalTexture.VertexElements ); basicEffect = new BasicEffect( graphics.GraphicsDevice, null ); basicEffect.Alpha = 1.0f; basicEffect.DiffuseColor = new Vector3( 1.0f, 0.0f, 1.0f ); basicEffect.SpecularColor = new Vector3( 0.25f, 0.25f, 0.25f ); basicEffect.SpecularPower = 5.0f; basicEffect.AmbientLightColor = new Vector3( 0.75f, 0.75f, 0.75f ); basicEffect.DirectionalLight0.Enabled = true; basicEffect.DirectionalLight0.DiffuseColor = Vector3.One; basicEffect.DirectionalLight0.Direction = Vector3.Normalize( new Vector3( 1.0f, -1.0f, -1.0f ) ); basicEffect.DirectionalLight0.SpecularColor = Vector3.One; basicEffect.DirectionalLight1.Enabled = true; basicEffect.DirectionalLight1.DiffuseColor = new Vector3( 0.5f, 0.5f, 0.5f ); basicEffect.DirectionalLight1.Direction = Vector3.Normalize( new Vector3( -1.0f, -1.0f, 1.0f ) ); basicEffect.DirectionalLight1.SpecularColor = new Vector3( 0.5f, 0.5f, 0.5f ); basicEffect.LightingEnabled = true; basicEffect.World = worldMatrix; basicEffect.View = viewMatrix; basicEffect.Projection = projectionMatrix; } private void InitializeCube() { cubeVertices = new VertexPositionNormalTexture[36]; Vector3 topLeftFront = new Vector3( -1.0f, 1.0f, 1.0f ); Vector3 bottomLeftFront = new Vector3( -1.0f, -1.0f, 1.0f ); Vector3 topRightFront = new Vector3( 1.0f, 1.0f, 1.0f ); Vector3 bottomRightFront = new Vector3( 1.0f, -1.0f, 1.0f ); Vector3 topLeftBack = new Vector3( -1.0f, 1.0f, -1.0f ); Vector3 topRightBack = new Vector3( 1.0f, 1.0f, -1.0f ); Vector3 bottomLeftBack = new Vector3( -1.0f, -1.0f, -1.0f ); Vector3 bottomRightBack = new Vector3( 1.0f, -1.0f, -1.0f ); Vector2 textureTopLeft = new Vector2( 0.0f, 0.0f ); Vector2 textureTopRight = new Vector2( 1.0f, 0.0f ); Vector2 textureBottomLeft = new Vector2( 0.0f, 1.0f ); Vector2 textureBottomRight = new Vector2( 1.0f, 1.0f ); Vector3 frontNormal = new Vector3( 0.0f, 0.0f, 1.0f ); Vector3 backNormal = new Vector3( 0.0f, 0.0f, -1.0f ); Vector3 topNormal = new Vector3( 0.0f, 1.0f, 0.0f ); Vector3 bottomNormal = new Vector3( 0.0f, -1.0f, 0.0f ); Vector3 leftNormal = new Vector3( -1.0f, 0.0f, 0.0f ); Vector3 rightNormal = new Vector3( 1.0f, 0.0f, 0.0f ); // Front face. cubeVertices[0] = new VertexPositionNormalTexture( topLeftFront, frontNormal, textureTopLeft ); cubeVertices[1] = new VertexPositionNormalTexture( bottomLeftFront, frontNormal, textureBottomLeft ); cubeVertices[2] = new VertexPositionNormalTexture( topRightFront, frontNormal, textureTopRight ); cubeVertices[3] = new VertexPositionNormalTexture( bottomLeftFront, frontNormal, textureBottomLeft ); cubeVertices[4] = new VertexPositionNormalTexture( bottomRightFront, frontNormal, textureBottomRight ); cubeVertices[5] = new VertexPositionNormalTexture( topRightFront, frontNormal, textureTopRight ); // Back face. cubeVertices[6] = new VertexPositionNormalTexture( topLeftBack, backNormal, textureTopRight ); cubeVertices[7] = new VertexPositionNormalTexture( topRightBack, backNormal, textureTopLeft ); cubeVertices[8] = new VertexPositionNormalTexture( bottomLeftBack, backNormal, textureBottomRight ); cubeVertices[9] = new VertexPositionNormalTexture( bottomLeftBack, backNormal, textureBottomRight ); cubeVertices[10] = new VertexPositionNormalTexture( topRightBack, backNormal, textureTopLeft ); cubeVertices[11] = new VertexPositionNormalTexture( bottomRightBack, backNormal, textureBottomLeft ); // Top face. cubeVertices[12] = new VertexPositionNormalTexture( topLeftFront, topNormal, textureBottomLeft ); cubeVertices[13] = new VertexPositionNormalTexture( topRightBack, topNormal, textureTopRight ); cubeVertices[14] = new VertexPositionNormalTexture( topLeftBack, topNormal, textureTopLeft ); cubeVertices[15] = new VertexPositionNormalTexture( topLeftFront, topNormal, textureBottomLeft ); cubeVertices[16] = new VertexPositionNormalTexture( topRightFront, topNormal, textureBottomRight ); cubeVertices[17] = new VertexPositionNormalTexture( topRightBack, topNormal, textureTopRight ); // Bottom face. cubeVertices[18] = new VertexPositionNormalTexture( bottomLeftFront, bottomNormal, textureTopLeft ); cubeVertices[19] = new VertexPositionNormalTexture( bottomLeftBack, bottomNormal, textureBottomLeft ); cubeVertices[20] = new VertexPositionNormalTexture( bottomRightBack, bottomNormal, textureBottomRight ); cubeVertices[21] = new VertexPositionNormalTexture( bottomLeftFront, bottomNormal, textureTopLeft ); cubeVertices[22] = new VertexPositionNormalTexture( bottomRightBack, bottomNormal, textureBottomRight ); cubeVertices[23] = new VertexPositionNormalTexture( bottomRightFront, bottomNormal, textureTopRight ); // Left face. cubeVertices[24] = new VertexPositionNormalTexture( topLeftFront, leftNormal, textureTopRight ); cubeVertices[25] = new VertexPositionNormalTexture( bottomLeftBack, leftNormal, textureBottomLeft ); cubeVertices[26] = new VertexPositionNormalTexture( bottomLeftFront, leftNormal, textureBottomRight ); cubeVertices[27] = new VertexPositionNormalTexture( topLeftBack, leftNormal, textureTopLeft ); cubeVertices[28] = new VertexPositionNormalTexture( bottomLeftBack, leftNormal, textureBottomLeft ); cubeVertices[29] = new VertexPositionNormalTexture( topLeftFront, leftNormal, textureTopRight ); // Right face. cubeVertices[30] = new VertexPositionNormalTexture( topRightFront, rightNormal, textureTopLeft ); cubeVertices[31] = new VertexPositionNormalTexture( bottomRightFront, rightNormal, textureBottomLeft ); cubeVertices[32] = new VertexPositionNormalTexture( bottomRightBack, rightNormal, textureBottomRight ); cubeVertices[33] = new VertexPositionNormalTexture( topRightBack, rightNormal, textureTopRight ); cubeVertices[34] = new VertexPositionNormalTexture( topRightFront, rightNormal, textureTopLeft ); cubeVertices[35] = new VertexPositionNormalTexture( bottomRightBack, rightNormal, textureBottomRight ); vertexBuffer = new VertexBuffer( graphics.GraphicsDevice, VertexPositionNormalTexture.SizeInBytes * cubeVertices.Length, ResourceUsage.None, ResourceManagementMode.Automatic ); vertexBuffer.SetData<VertexPositionNormalTexture>( cubeVertices ); } protected override void UnloadGraphicsContent( bool unloadAllContent ) { if (unloadAllContent == true) { content.Unload(); } } protected override void Update( GameTime gameTime ) { // Allows the default game to exit on Xbox 360 and Windows. if (GamePad.GetState( PlayerIndex.One ).Buttons.Back == ButtonState.Pressed) this.Exit(); base.Update( gameTime ); } protected override void Draw( GameTime gameTime ) { graphics.GraphicsDevice.Clear( Color.CornflowerBlue ); graphics.GraphicsDevice.RenderState.CullMode = CullMode.CullClockwiseFace; graphics.GraphicsDevice.VertexDeclaration = basicEffectVertexDeclaration; graphics.GraphicsDevice.Vertices[0].SetSource( vertexBuffer, 0, VertexPositionNormalTexture.SizeInBytes ); // This code would go between a device // BeginScene-EndScene block. basicEffect.Begin(); foreach (EffectPass pass in basicEffect.CurrentTechnique.Passes) { pass.Begin(); graphics.GraphicsDevice.DrawPrimitives( PrimitiveType.TriangleList, 0, 12 ); pass.End(); } basicEffect.End(); base.Draw( gameTime ); } } |
