带中心的旋转矩阵

Question

如何在此示例或任何示例中计算中心向量.WolframAlpha:http://www.wolframalpha.com/input/？i = rotate +90+degrees+center+%283%2C0%29

Answer 1

均匀坐标:

            [ cos(theta) -sin(theta) 0 ]
Rotate    = [ sin(theta)  cos(theta) 0 ]
            [      0           0     1 ]

            [ 1 0 x ]
Translate = [ 0 1 y ]
            [ 0 0 1 ]

因此,为了执行转换,您需要乘以Translate(x, y) * Rotate(theta) * Translate(-x, -y)并获得转换矩阵.