顶点定义与基本形状汇出.PPT

* 範例二：顯示出三個軸線 4.在draw()定義世界矩陣與投影矩陣，並顯示出結果 protected override void Draw(GameTime gameTime) { …….. // Draw the 3D axis effect.Begin(); foreach (EffectPass CurrentPass in effect.CurrentTechnique.Passes) { CurrentPass.Begin(); graphics.GraphicsDevice.DrawPrimitives(PrimitiveType.PointList, 0, 6); CurrentPass.End(); } effect.End(); base.Draw(gameTime); } } * 範例三：顯示出一個立方體 1. 定義八個頂點 2. 定義十二個三角形，其中兩個三角形形成一平面 3. 繪出 * 範例三：顯示出一個立方體 定義八個頂點 protected override void Initialize() { ……… VertexPositionColor[] vertices = new VertexPositionColor[8]; // X, Y, Z axis vertices[0] = new VertexPositionColor(new Vector3(-1.0f, -1.0f, -1.0f), Color.White); vertices[1] = new VertexPositionColor(new Vector3(-1.0f, 1.0f, -1.0f), Color.White); vertices[2] = new VertexPositionColor(new Vector3(1.0f, 1.0f, -1.0f), Color.White); vertices[3] = new VertexPositionColor(new Vector3(1.0f, -1.0f, -1.0f), Color.White); vertices[4] = new VertexPositionColor(new Vector3(-1.0f, -1.0f, 1.0f), Color.White); vertices[5] = new VertexPositionColor(new Vector3(-1.0f, 1.0f, 1.0f), Color.White); vertices[6] = new VertexPositionColor(new Vector3(1.0f, 1.0f, 1.0f), Color.White); vertices[7] = new VertexPositionColor(new Vector3(1.0f, -1.0f, 1.0f), Color.White); vertexBuffer = new VertexBuffer(this.GraphicsDevice, 8*VertexPositionColor.SizeInBytes, BufferUsage.WriteOnly); // 產生 頂點緩衝區 vertexBuffer.SetDataVertexPositionColor(vertices); // 複製 頂點資料 * 範例三：顯示出一個立方體 2. 在initialize定義六個平面，共十二個三角形 short[] vertexIndices = new short[36]; // 36 個 頂點索引 vertexIndices[0] = 3; vertexIndices[1] = 2; vertexIndices[2] = 1; // 後面 vertexIndices[3] = 3; vertexIndices[4] = 1; vertexIndices[5] = 0; vertexIndices[6] = 4; vertexIndices[7] = 5; vertexIndices[8] = 6; // 前面 vertexIndices[9] = 4; vertexIn