# -*- coding: utf-8 -*-
# -------------------------------------------
# quidam_02.py 旋转、缩放、改变视点和参考点
# -------------------------------------------
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *
import numpy as np
IS_PERSPECTIVE = True # 透视投影
VIEW = np.array([-0.8, 0.8, -0.8, 0.8, 1.0, 20.0]) # 视景体的left/right/bottom/top/near/far六个面
SCALE_K = np.array([1.0, 1.0, 1.0]) # 模型缩放比例
EYE = np.array([0.0, 0.0, 2.0]) # 眼睛的位置（默认z轴的正方向）
LOOK_AT = np.array([0.0, 0.0, 0.0]) # 瞄准方向的参考点（默认在坐标原点）
EYE_UP = np.array([0.0, 1.0, 0.0]) # 定义对观察者而言的上方（默认y轴的正方向）
WIN_W, WIN_H = 640, 480 # 保存窗口宽度和高度的变量
LEFT_IS_DOWNED = False # 鼠标左键被按下
MOUSE_X, MOUSE_Y = 0, 0 # 考察鼠标位移量时保存的起始位置
def getposture():
global EYE, LOOK_AT
dist = np.sqrt(np.power((EYE-LOOK_AT), 2).sum())
if dist > 0:
phi = np.arcsin((EYE[1]-LOOK_AT[1])/dist)
theta = np.arcsin((EYE[0]-LOOK_AT[0])/(dist*np.cos(phi)))
else:
phi = 0.0
theta = 0.0
return dist, phi, theta
DIST, PHI, THETA = getposture() # 眼睛与观察目标之间的距离、仰角、方位角
def init():
glClearColor(0.0, 0.0, 0.0, 1.0) # 设置画布背景色。注意：这里必须是4个参数
glEnable(GL_DEPTH_TEST) # 开启深度测试，实现遮挡关系
glDepthFunc(GL_LEQUAL) # 设置深度测试函数（GL_LEQUAL只是选项之一）
def draw():
global IS_PERSPECTIVE, VIEW
global EYE, LOOK_AT, EYE_UP
global SCALE_K
global WIN_W, WIN_H
# 清除屏幕及深度缓存
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
# 设置投影（透视投影）
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
if WIN_W > WIN_H:
if IS_PERSPECTIVE:
glFrustum(VIEW[0]*WIN_W/WIN_H, VIEW[1]*WIN_W/WIN_H, VIEW[2], VIEW[3], VIEW[4], VIEW[5])
else:
glOrtho(VIEW[0]*WIN_W/WIN_H, VIEW[1]*WIN_W/WIN_H, VIEW[2], VIEW[3], VIEW[4], VIEW[5])
else:
if IS_PERSPECTIVE:
glFrustum(VIEW[0], VIEW[1], VIEW[2]*WIN_H/WIN_W, VIEW[3]*WIN_H/WIN_W, VIEW[4], VIEW[5])
else:
glOrtho(VIEW[0], VIEW[1], VIEW[2]*WIN_H/WIN_W, VIEW[3]*WIN_H/WIN_W, VIEW[4], VIEW[5])
# 设置模型视图
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
# 几何变换
glScale(SCALE_K[0], SCALE_K[1], SCALE_K[2])
# 设置视点
gluLookAt(
EYE[0], EYE[1], EYE[2],
LOOK_AT[0], LOOK_AT[1], LOOK_AT[2],
EYE_UP[0], EYE_UP[1], EYE_UP[2]
)
# 设置视口
glViewport(0, 0, WIN_W, WIN_H)
# ---------------------------------------------------------------
glBegin(GL_LINES) # 开始绘制线段（世界坐标系）
# 以红色绘制x轴
glColor4f(1.0, 0.0, 0.0, 1.0) # 设置当前颜色为红色不透明
glVertex3f(-0.8, 0.0, 0.0) # 设置x轴顶点（x轴负方向）
glVertex3f(0.8, 0.0, 0.0) # 设置x轴顶点（x轴正方向）
# 以绿色绘制y轴
glColor4f(0.0, 1.0, 0.0, 1.0) # 设置当前颜色为绿色不透明
glVertex3f(0.0, -0.8, 0.0) # 设置y轴顶点（y轴负方向）
glVertex3f(0.0, 0.8, 0.0) # 设置y轴顶点（y轴正方向）
# 以蓝色绘制z轴
glColor4f(0.0, 0.0, 1.0, 1.0) # 设置当前颜色为蓝色不透明
glVertex3f(0.0, 0.0, -0.8) # 设置z轴顶点（z轴负方向）
glVertex3f(0.0, 0.0, 0.8) # 设置z轴顶点（z轴正方向）
glEnd() # 结束绘制线段
# ---------------------------------------------------------------
glBegin(GL_TRIANGLES) # 开始绘制三角形（z轴负半区）
glColor4f(1.0, 0.0, 0.0, 1.0) # 设置当前颜色为红色不透明
glVertex3f(-0.5, -0.366, -0.5) # 设置三角形顶点
glColor4f(0.0, 1.0, 0.0, 1.0) # 设置当前颜色为绿色不透明
glVertex3f(0.5, -0.366, -0.5) # 设置三角形顶点
glColor4f(0.0, 0.0, 1.0, 1.0) # 设置当前颜色为蓝色不透明
glVertex3f(0.0, 0.5, -0.5) # 设置三角形顶点
glEnd() # 结束绘制三角形
# ---------------------------------------------------------------
glBegin(GL_TRIANGLES) # 开始绘制三角形（z轴正半区）
glColor4f(1.0, 0.0, 0.0, 1.0) # 设置当前颜色为红色不透明
glVertex3f(-0.5, 0.5, 0.5) # 设置三角形顶点
glColor4f(0.0, 1.0, 0.0, 1.0) # 设置当前颜色为绿色不透明
glVertex3f(0.5, 0.5, 0.5) # 设置三角形顶点
glColor4f(0.0, 0.0, 1.0, 1.0) # 设置当前颜色为蓝色不透明
glVertex3f(0.0, -0.366, 0.5) # 设置三角形顶点
glEnd() # 结束绘制三角形
# ---------------------------------------------------------------
glutSwapBuffers() # 切换缓冲区，以显示绘制内容
def reshape(width, height):
global WIN_W, WIN_H
WIN_W, WIN_H = width, height
glutPostRedisplay()
def mouseclick(button, state, x, y):
global SCALE_K
global LEFT_IS_DOWNED
global MOUSE_X, MOUSE_Y
MOUSE_X, MOUSE_Y = x, y
if button == GLUT_LEFT_BUTTON:
LEFT_IS_DOWNED = state==GLUT_DOWN
elif button == 3:
SCALE_K *= 1.05
glutPostRedisplay()
elif button == 4:
SCALE_K *= 0.95
glutPostRedisplay()
def mousemotion(x, y):
global LEFT_IS_DOWNED
global EYE, EYE_UP
global MOUSE_X, MOUSE_Y
global DIST, PHI, THETA
global WIN_W, WIN_H
if LEFT_IS_DOWNED:
dx = MOUSE_X - x
dy = y - MOUSE_Y
MOUSE_X, MOUSE_Y = x, y
PHI += 2*np.pi*dy/WIN_H
PHI %= 2*np.pi
THETA += 2*np.pi*dx/WIN_W
THETA %= 2*np.pi
r = DIST*np.cos(PHI)
EYE[1] = DIST*np.sin(PHI)
EYE[0] = r*np.sin(THETA)
EYE[2] = r*np.cos(THETA)
if 0.5*np.pi < PHI < 1.5*np.pi:
EYE_UP[1] = -1.0
else:
EYE_UP[1] = 1.0
glutPostRedisplay()
def keydown(key, x, y):
global DIST, PHI, THETA
global EYE, LOOK_AT, EYE_UP
global IS_PERSPECTIVE, VIEW
if key in [b'x', b'X', b'y', b'Y', b'z', b'Z']:
if key == b'x': # 瞄准参考点 x 减小
LOOK_AT[0] -= 0.01
elif key == b'X': # 瞄准参考 x 增大
LOOK_AT[0] += 0.01
elif key == b'y': # 瞄准参考点 y 减小
LOOK_AT[1] -= 0.01
elif key == b'Y': # 瞄准参考点 y 增大
LOOK_AT[1] += 0.01
elif key == b'z': # 瞄准参考点 z 减小
LOOK_AT[2] -= 0.01
elif key == b'Z': # 瞄准参考点 z 增大
LOOK_AT[2] += 0.01
DIST, PHI, THETA = getposture()
glutPostRedisplay()
elif key == b'\r': # 回车键，视点前进
EYE = LOOK_AT + (EYE - LOOK_AT) * 0.9
DIST, PHI, THETA = getposture()
glutPostRedisplay()
elif key == b'\x08': # 退格键，视点后退
EYE = LOOK_AT + (EYE - LOOK_AT) * 1.1
DIST, PHI, THETA = getposture()
glutPostRedisplay()
elif key == b' ': # 空格键，切换投影模式
IS_PERSPECTIVE = not IS_PERSPECTIVE
glutPostRedisplay()
if __name__ == "__main__":
glutInit()
displayMode = GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH
glutInitDisplayMode(displayMode)
glutInitWindowSize(WIN_W, WIN_H)
glutInitWindowPosition(300, 200)
glutCreateWindow('Quidam Of OpenGL')
init() # 初始化画布
glutDisplayFunc(draw) # 注册回调函数draw()
glutReshapeFunc(reshape) # 注册响应窗口改变的函数reshape()
glutMouseFunc(mouseclick) # 注册响应鼠标点击的函数mouseclick()
glutMotionFunc(mousemotion) # 注册响应鼠标拖拽的函数mousemotion()
glutKeyboardFunc(keydown) # 注册键盘输入的函数keydown()
glutMainLoop() # 进入glut主循环
结果显示：
