C# DirectX编程对基本三角形应用平移变换矩阵

Love The Way You Lie 2023-01-09 03:52 113阅读 0赞

前文；

[https://blog.csdn.net/bcbobo21cn/article/details/112729045][https_blog.csdn.net_bcbobo21cn_article_details_112729045]

平移变换矩阵的定义如下；

![20210120201621950.png][]

除了对角全为1，以及px、py、pz之外，都为0；px、py、pz 是三个轴的平移量；

把一个三维物体各顶点坐标乘以T(p)矩阵，该物体就会被平移px、py、pz；

先在窗体级定义一个矩阵，Microsoft.DirectX.Matrix m1; Render()函数如下；其他代码见前文的前文；

public void Render()
            {
                if (device == null)   //如果device为空则不渲染
                {
                    return;
                }
                device.Clear(ClearFlags.Target, Color.DarkSlateBlue, 1.0f, 0);  //清除windows界面为深蓝色
                device.BeginScene();
    
                //在此添加渲染图形代码
                CustomVertex.TransformedColored[] vertices = new CustomVertex.TransformedColored[3];//定义顶点
                vertices[0].Position = new Vector4(100f, 200f, 0f, 1f);
                vertices[0].Color = Color.Red.ToArgb();
                vertices[1].Position = new Vector4(this.Width / 2, 50f, 0f, 1f);
                vertices[1].Color = Color.Green.ToArgb();
                vertices[2].Position = new Vector4(this.Width - 150f, 100f, 0f, 1f);
                vertices[2].Color = Color.Yellow.ToArgb();
    
                m1.M11 = 1; m1.M12 = 0; m1.M13 = 0; m1.M14 = 0;
                m1.M21 = 0; m1.M22 = 1; m1.M23 = 0; m1.M24 = 0;
                m1.M31 = 0; m1.M32 = 0; m1.M33 = 1; m1.M34 = 0;
                m1.M41 = -75.0f; m1.M42 = 5.0f; m1.M43 = 25.0f; m1.M44 = 1;
    
                Vector4 v41 = new Vector4(100f, 200f, 0f, 1f);
                v41.Transform(m1);
                vertices[0].Position = v41;
                Vector4 v42 = new Vector4(this.Width / 2, 50f, 0f, 1f);
                v42.Transform(m1);
                vertices[1].Position = v42;
                Vector4 v43 = new Vector4(this.Width - 150f, 100f, 0f, 1f);
                v43.Transform(m1);
                vertices[2].Position = v43;
    
                device.VertexFormat = CustomVertex.TransformedColored.Format;
                device.DrawUserPrimitives(PrimitiveType.TriangleList, 1, vertices);
    
                device.EndScene();
                device.Present();
            }

定义m1之后把m1赋值为平移变换矩阵；平移量在第四行赋值；然后对三个顶点用m1作变换；

未应用m1进行变换和进行了变换的输出对比如下；

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70][]

如只对 vertices\[0\].Position 应用m1进行变换则输出如下；

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70 1][]

有时间再继续；

[https_blog.csdn.net_bcbobo21cn_article_details_112729045]: https://blog.csdn.net/bcbobo21cn/article/details/112729045
[20210120201621950.png]: /images/20221119/faed4a5516b0499aa50f6390a6a319c5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70]: /images/20221119/b9eb6806d97a408688074c1c8af12e65.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JjYm9ibzIxY24_size_16_color_FFFFFF_t_70 1]: /images/20221119/47b46fc609f64addbb07fd55d8bac39d.png