Rotating a rectangle

[deanhystad]

A pygame program that tumbles a cube. Rotations about x, y and z.

import pygame, math
from pygame.locals import *
     
class Point():
    '''A point in space'''
    def __init__(self, x, y, z):
        self.x = x
        self.y = y
        self.z = z

    def projection(self):
        '''Return projection on xy plane.  Not doing perspective'''
        return self.x, self.y

    def move(self, x=0, y=0, z=0):
        '''Move self in x, y and z'''
        self.x += x
        self.y += y
        self.z += z

    def rotate_x(self, degrees, center=(0, 0, 0)):
        '''Rotate self about x axis
        degrees is angle of rotation measured in degrees
        center is the center of rotation
        '''
        cx, cy, cz = center
        y = self.y - cy
        z = self.z - cz
        d = math.hypot(y, z)
        theta  = math.atan2(y, z) + degrees * math.pi/180
        self.z = cz + d * math.cos(theta)
        self.y = cy + d * math.sin(theta)

    def rotate_y(self, degrees, center=(0, 0, 0)):
        '''Rotate self about y axis
        degrees is angle of rotation measured in degrees
        center is the center of rotation
        '''
        cx, cy, cz = center
        x = self.x - cx
        z = self.z - cz
        d = math.hypot(x, z)
        theta  = math.atan2(x, z) + degrees * math.pi/180
        self.z = cz + d * math.cos(theta)
        self.x = cx + d * math.sin(theta)

    def rotate_z(self, degrees, center=(0, 0, 0)):
        '''Rotate self about z axis
        degrees is angle of rotation measured in degrees
        center is the center of rotation
        '''
        cx, cy, cz = center
        x = self.x - cx
        y = self.y - cy
        d = math.hypot(y, x)
        theta  = math.atan2(y, x) + degrees * math.pi/180
        self.x = cx + d * math.cos(theta)
        self.y = cy + d * math.sin(theta)

    def __str__(self):
        return f'({self.x}, {self.y}, {self.z})'
 
class Cube():
    '''A 3D cube'''
    def __init__(self, size, center=(0, 0, 0)):
        x, y, z = center
        a = size/2
        self.points = [
            Point(x-a, y-a, z+a),
            Point(x+a, y-a, z+a),
            Point(x+a, y+a, z+a),
            Point(x-a, y+a, z+a),
            Point(x-a, y-a, z-a),
            Point(x+a, y-a, z-a),
            Point(x+a, y+a, z-a),
            Point(x-a, y+a, z-a),
        ]

    def center(self):
        '''Calculate center of cube'''
        x = y = z = 0
        for point in self.points:
            x += point.x
            y += point.y
            z += point.z
        return x/8, y/8, z/8

    def move(self, x=0, y=0, z=0):
        '''Move cube in x, y and z'''
        for point in self.points:
            point.move(x, y, z)

    def rotate_x(self, degrees, center=None):
        '''Rotate self about x axis
        degrees is angle of rotation measured in degrees
        center is the center of rotation.  If center not
        provided rotate about self.center.
        '''
        if center is None:
            center = self.center()
        for point in self.points:
            point.rotate_x(degrees, center)

    def rotate_y(self, degrees, center=None):
        '''Rotate self about y axis
        degrees is angle of rotation measured in degrees
        center is the center of rotation.  If center not
        provided rotate about self.center.
        '''
        if center is None:
            center = self.center()
        for point in self.points:
            point.rotate_y(degrees, center)

    def rotate_z(self, degrees, center=None):
        '''Rotate self about z axis
        degrees is angle of rotation measured in degrees
        center is the center of rotation.  If center not
        provided rotate about self.center.
        '''
        if center is None:
            center = self.center()
        for point in self.points:
            point.rotate_z(degrees, center)

    def draw(self, surface, color=(255, 255, 255)):
        '''Draw self on surface'''
        for a, b in zip([0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3], [1, 2, 3, 0, 5, 6, 7, 4, 4, 5, 6, 7]):
            pygame.draw.line(surface, color, self.points[a].projection(), self.points[b].projection())

    def __str__(self):
        return f"{{{', '.join([str(point) for point in self.points])}}}"

FPS = 30
pygame.init()
DISPLAYSURF = pygame.display.set_mode((200, 200))
pygame.display.set_caption('Cube')
fpsClock = pygame.time.Clock()
cube = Cube(60, (160, 100, 0))
running = True
while running:
    for event in pygame.event.get():
        if event.type == QUIT:
            running = False
            break
       
    DISPLAYSURF.fill((0, 0, 0))
    cube.rotate_x(1)
    cube.rotate_y(1)
    cube.rotate_z(1, (100, 100, 0))
    cube.draw(DISPLAYSURF)
    pygame.display.flip()
    fpsClock.tick(FPS)
  
pygame.quit()