如何实现Vispy中按Z键多次旋转网格立方体？

你每次按下Z键时，都会创建一个新的MatrixTransform实例并赋值给cube2.transform，这个新变换只会将立方体从初始状态旋转90度。第二次按下时，你又重新创建了一个同样的变换，立方体的最终状态还是旋转90度，所以看起来没有变化。

需要复用立方体已有的变换对象，在现有变换的基础上叠加旋转操作。具体步骤：

• 初始化cube2时，给它分配一个初始的MatrixTransform
• 按下Z键时，直接对cube2.transform执行旋转操作，而不是重新创建变换

from vispy import app, scene, geometry
import numpy as np

class MonCanvas(scene.SceneCanvas):
    def on_key_press(self,event):
        global cube1, cube2, c1data, c2data
        if event.text == 'a':
            c1data.set_face_colors([[0,0,1,1],[0,0,1,1],[0,1,0,1],[0,1,0,1],[1,1,1,1],[1,1,1,1],[1,1,0,1],[1,1,0,1],[1,0,0,1],[1,0,0,1],[1,0.5,0,1],[1,0.5,0,1]])
            cube1.mesh_data_changed()
        if event.text == 'z':
            # 直接在现有变换上叠加旋转
            cube2.transform.rotate(90,(0,0,1))

fenetre = MonCanvas(title="Fenêtre principale", size=(2000,1000), keys="interactive")

view = fenetre.central_widget.add_view()
view.camera = 'turntable'
view.camera.distance = 10

c1data = geometry.MeshData(vertices = np.array([[0.5,0.5,-0.5],[0.5,-0.5,-0.5],[-0.5,0.5,-0.5],[-0.5,-0.5,-0.5],[0.5,0.5,0.5],[0.5,-0.5,0.5],[-0.5,0.5,0.5],[-0.5,-0.5,0.5]]), edges = np.array([[0,1],[0,2],[0,4],[3,1],[3,2],[3,7],[5,1],[5,4],[5,7],[6,2],[6,4],[6,7]]), faces = np.array([[1,2,3],[0,1,2],[5,6,7],[4,5,6],[0,1,5],[0,5,4],[2,3,7],[2,7,6],[1,3,7],[1,7,5],[0,2,6],[0,6,4]]))
c1data.set_face_colors([[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1],[0,0,1,1]])
cube1 = scene.visuals.Mesh(meshdata = c1data)
view.add(cube1)

c2data = geometry.MeshData(vertices = np.array([[0.5,0.5,0.5],[0.5,-0.5,0.5],[-0.5,0.5,0.5],[-0.5,-0.5,0.5],[0.5,0.5,1.5],[0.5,-0.5,1.5],[-0.5,0.5,1.5],[-0.5,-0.5,1.5]]), edges = np.array([[0,1],[0,2],[0,4],[3,1],[3,2],[3,7],[5,1],[5,4],[5,7],[6,2],[6,4],[6,7]]), faces = np.array([[1,2,3],[0,1,2],[5,6,7],[4,5,6],[0,1,5],[0,5,4],[2,3,7],[2,7,6],[1,3,7],[1,7,5],[0,2,6],[0,6,4]]))
c2data.set_face_colors([[0,0,1,1],[0,0,1,1],[0,1,0,1],[0,1,0,1],[1,1,1,1],[1,1,1,1],[1,1,0,1],[1,1,0,1],[1,0,0,1],[1,0,0,1],[1,0.5,0,1],[1,0.5,0,1]])
cube2 = scene.visuals.Mesh(meshdata = c2data)
# 初始化时给cube2分配一个MatrixTransform实例
cube2.transform = scene.transforms.MatrixTransform()
view.add(cube2)

fenetre.show()
app.run()

• 初始化cube2时，添加了cube2.transform = scene.transforms.MatrixTransform()，确保立方体有一个可复用的变换对象
• Z键处理逻辑从创建新变换并赋值，改为直接调用cube2.transform.rotate(90,(0,0,1))，在现有变换基础上叠加旋转

内容的提问来源于stack exchange，提问作者Emilie Lemaire