Python 3学习笔记(17):PyOpenGL之组合螺钉
程序员文章站
2022-03-25 17:24:33
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目的
组合螺帽、螺杆、螺纹成螺钉,可用箭头键切换视角。
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内容
把螺钉的三个部分在适当的位置画出,组成螺钉。螺杆不用修改和移动,螺纹必须旋转来吻合螺杆,螺帽需要旋转和移动,并放在合适的位置。
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代码
#coding:utf-8
import sys
from math import pi as PI
from math import sin, cos
from math import sqrt
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *
#将指定为三个坐标组的法线向量换算。
def ReduceToUnit(vector):
# Calculate the length of the vector
length = sqrt((vector[0]*vector[0]) + (vector[1]*vector[1]) +(vector[2]*vector[2]));
#Keep the program from blowing up by providing an exceptable
#value for vectors that may calculated too close to zero.
if (length == 0.0):
length = 1.0
#Dividing each element by the length will result in a unit normal vector.
vector[0] /= length
vector[1] /= length
vector[2] /= length
# Points p1, p2, & p3 specified in counter clock-wise order
# float v[3][3], float out[3]
def calcNormal(v,out):
#float v1[3],v2[3];
v1=[0.0 for i in range(3)]
v2=[0.0 for i in range(3)]
out=[0.0 for i in range(3)]
xx = 0
yy = 1
zz = 2
# Calculate two vectors from the three points
v1[xx] = v[0][xx] - v[1][xx]
v1[yy] = v[0][yy] - v[1][yy]
v1[zz] = v[0][zz] - v[1][zz]
v2[xx] = v[1][xx] - v[2][xx]
v2[yy] = v[1][yy] - v[2][yy]
v2[zz] = v[1][zz] - v[2][zz]
# Take the cross product of the two vectors to get
# the normal vector which will be stored in out
out[xx] = v1[yy]*v2[zz] - v1[zz]*v2[yy]
out[yy] = v1[zz]*v2[xx] - v1[xx]*v2[zz]
out[zz] = v1[xx]*v2[yy] - v1[yy]*v2[xx]
# Normalize the vector (shorten length to one)
ReduceToUnit(out)
def RenderHead():
global x,y,angle # Calculated positions
height = 25.0 # Thickness of the head
diameter = 30.0 # Diameter of the head
#float normal[3],corners[4][3]; // Storeage of vertices and normals
corners = [[0.0 for i in range(3)] for i in range(4)]
normal=[0.0 for i in range(3)]
step = (PI/3.0) # step = 1/6th of a circle = hexagon
# Set material color for head of bolt
glColor3f(0.0, 0.0, 0.7)
# ----------开始一个三角形扇面覆盖 螺帽顶面------
glFrontFace(GL_CCW)
glBegin(GL_TRIANGLE_FAN)
#All the normals for the top of the bolt point straight up the z axis.
glNormal3f(0.0, 0.0, 1.0)
# Center of fan is at the origin
glVertex3f(0.0, 0.0, height/2.0)
#把圆圈分成6个部分,然后开始下降点来绘制扇面. 避免使用glFrontFace()进行状态改变
# 第一个和最后一个顶点封闭扇面
glVertex3f(0.0, diameter, height/2.0)
angle=(2.0*PI)-step
while angle>0 :
#Calculate x and y position of the next vertex
x = diameter* sin(angle)
y = diameter* cos(angle)
# Specify the next vertex for the triangle fan
glVertex3f(x, y, height/2.0)
angle-=step
# Last vertex closes the fan
glVertex3f(0.0, diameter, height/2.0)
glEnd()
# ---------开始一个三角形扇面覆盖 螺帽底面--------
glBegin(GL_TRIANGLE_FAN)
glNormal3f(0.0, 0.0, -1.0)
# Center of fan is at the origin
glVertex3f(0.0, 0.0, -height/2.0)
angle=0
while angle<(2.0*PI)-step :
#Calculate x and y position of the next vertex
x = diameter* sin(angle)
y = diameter* cos(angle)
# Specify the next vertex for the triangle fan
glVertex3f(x, y, -height/2.0)
angle+=step
# Last vertex closes the fan
glVertex3f(0.0, diameter, -height/2.0)
glEnd()
# ---------开始一个四角形覆盖 螺帽侧面
glBegin(GL_QUADS);
angle=0
while angle<(2.0*PI)-step :
x = diameter* sin(angle)
y = diameter* cos(angle)
#start at bottom of head
corners[0][0] = x
corners[0][1] = y
corners[0][2] = -height/2.0
#extrude to top of head
corners[1][0] = x
corners[1][1] = y
corners[1][2] = height/2.0
#Calculate the next hex point
x = diameter* sin(angle+step)
y = diameter* cos(angle+step)
#Make sure we aren't done before proceeding
if (angle+step < 3.1415*2.0):
#If we are done, just close the fan at a known coordinate.
corners[2][0] = x
corners[2][1] = y
corners[2][2] = height/2.0
corners[3][0] = x
corners[3][1] = y
corners[3][2] = -height/2.0
else:
corners[2][0] = 0.0
corners[2][1] = diameter
corners[2][2] = height/2.0
corners[3][0] = 0.0
corners[3][1] = diameter
corners[3][2] = -height/2.0
calcNormal(corners, normal)
glNormal3fv(normal)
glVertex3fv(corners[0])
glVertex3fv(corners[1])
glVertex3fv(corners[2])
glVertex3fv(corners[3])
angle+=step
glEnd()
def RenderShaft():
global x,z,angle # Calculated positions
height = 75.0 # Height of the cylinder
diameter = 20.0 # Diameter of the cylinder
#float normal[3],corners[2][3]; // Storeage of vertices and normals
corners = [[0.0 for i in range(3)] for i in range(2)]
normal=[0.0 for i in range(3)]
step = (PI/50.0) # Approximate the cylinder wall with 100 flat segments
# Set material color for head of bolt
glColor3f(0.0, 0.0, 0.7)
# ----------开始一个绘制螺杆------
glBegin(GL_QUAD_STRIP)
angle=(2.0*PI)
while angle>0 :
#Calculate x and y position of the next vertex
x = diameter* sin(angle)
z = diameter* cos(angle)
# Get the coordinate for this point and extrude the length of the cylinder.
corners[0][0] = x
corners[0][1] = -height/2.0
corners[0][2] = z
corners[1][0] = x
corners[1][1] = height/2.0
corners[1][2] = z
# Instead of using real normal to actual flat section
# Use what the normal would be if the surface was really
# curved. Since the cylinder goes up the Y axis, the normal
# points from the Y axis out directly through each vertex.
# Therefore we can use the vertex as the normal, as long as
# we reduce it to unit length first and assume the y component to be zero
normal[0] = corners[1][0]
normal[1] = 0.0
normal[2] = corners[1][2]
# Reduce to length of one and specify for this point
ReduceToUnit(normal)
glNormal3fv(normal)
glVertex3fv(corners[0])
glVertex3fv(corners[1])
angle-=step
#Make sure there are no gaps by extending last quad to the original location
glVertex3f(diameter*sin(2.0*PI),-height/2.0,diameter*cos(2.0*PI))
glVertex3f(diameter*sin(2.0*PI),height/2.0,diameter*cos(2.0*PI))
glEnd()
#--------Begin a new triangle fan to cover the bottom-----
glBegin(GL_TRIANGLE_FAN)
#Normal points down the Y axis
glNormal3f(0.0, -1.0, 0.0)
#Center of fan is at the origin
glVertex3f(0.0, -height/2.0, 0.0)
angle=(2.0*PI)
while angle>0 :
x = diameter* sin(angle)
z = diameter* cos(angle)
glVertex3f(x, -height/2.0, z)
angle-=step
# Be sure loop is closed by specifiying initial vertexon arc as the last too
glVertex3f(diameter*sin(2.0*PI),-height/2.0,diameter*cos(2.0*PI))
glEnd()
def RenderThread():
global x,y,z,angle # Calculate coordinates and step angle
height = 75.0 # Height of the threading
diameter = 20.0 # Diameter of the threading
#float normal[3],corners[2][3]; // Storeage of vertices and normals
corners = [[0.0 for i in range(3)] for i in range(4)]
normal=[0.0 for i in range(3)]
step = (PI/32.0) # one revolution
revolutions = 7.0 # How many time around the shaft
threadWidth = 2.0 # How wide is the thread
threadThick = 3.0 # How thick is the thread
zstep = 0.125 # How much does the thread move up the Z axis each time a new segment is drawn.
# Set material color for head of screw
glColor3f(0.0, 0.0, 0.4)
z = -height/2.0+2 # Starting spot almost to the end
angle=0
while angle<(2.0*PI)*revolutions :
#Calculate x and y position of the next vertex
x = diameter* sin(angle)
y = diameter* cos(angle)
# Store the next vertex next to the shaft.
corners[0][0] = x
corners[0][1] = y
corners[0][2] = z
# Calculate the position away from the shaft
x = (diameter+threadWidth)* sin(angle)
y = (diameter+threadWidth)* cos(angle)
corners[1][0] = x
corners[1][1] = y
corners[1][2] = z
# Calculate the next position away from the shaft
x = (diameter+threadWidth)*sin(angle+step)
y = (diameter+threadWidth)*cos(angle+step)
corners[2][0] = x
corners[2][1] = y
corners[2][2] = z + zstep
# Calculate the next position along the shaft
x = (diameter)*sin(angle+step)
y = (diameter)*cos(angle+step)
corners[3][0] = x
corners[3][1] = y
corners[3][2] = z+ zstep
# We'll be using triangels, so make counter clock-wise polygons face out
glFrontFace(GL_CCW)
glBegin(GL_TRIANGLES) # Start the top section of thread
# Calculate the normal for this segment
calcNormal(corners, normal)
glNormal3fv(normal)
# Draw two triangles to cover area
glVertex3fv(corners[0])
glVertex3fv(corners[1])
glVertex3fv(corners[2])
glVertex3fv(corners[2])
glVertex3fv(corners[3])
glVertex3fv(corners[0])
glEnd()
# Move the edge along the shaft slightly up the z axis to represent the bottom of the thread
corners[0][2] += threadThick
corners[3][2] += threadThick
# Recalculate the normal since points have changed, thistime it points in the opposite direction, so reverse it
calcNormal(corners, normal)
normal[0] = -normal[0]
normal[1] = -normal[1]
normal[2] = -normal[2]
# Switch to clock-wise facing out for underside of the thread.
glFrontFace(GL_CW)
# Draw the two triangles
glBegin(GL_TRIANGLES)
glNormal3fv(normal)
glVertex3fv(corners[0])
glVertex3fv(corners[1])
glVertex3fv(corners[2])
glVertex3fv(corners[2])
glVertex3fv(corners[3])
glVertex3fv(corners[0])
glEnd()
# Creep up the Z axis
z += zstep
angle+=step
def RenderScene():
global xRot,yRot
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
# Save the matrix state
glMatrixMode(GL_MODELVIEW)
glPushMatrix()
# 绕X轴和Y轴旋转(角度,x,y,z)
glRotatef(xRot, 1.0, 0.0, 0.0)
glRotatef(yRot, 0.0, 0.0, 1.0)
# Render just the Thread of the nut
RenderShaft()
glPushMatrix()
glRotatef(-90.0, 1.0, 0.0, 0.0)
RenderThread()
glTranslatef(0.0,0.0,45.0)
RenderHead()
glPopMatrix()
glPopMatrix()
#双缓冲的刷新模式; Swap buffers
glutSwapBuffers()
#设置渲染状态
def SetupRC():
# Light values and coordinates光照 值与坐标;环境光,漫射光,镜面光,光的坐标,
ambientLight = [0.4, 0.4, 0.4, 1.0 ]
diffuseLight = [0.7, 0.7, 0.7, 1.0 ]
specular = [ 0.9, 0.9, 0.9, 1.0]
lightPos = [ -50.0, 200.0, 200.0, 1.0]
specref = [ 0.6, 0.6, 0.6, 1.0]
glEnable(GL_DEPTH_TEST) # Hidden surface removal
glEnable(GL_CULL_FACE) # Do not calculate inside of solid object
glFrontFace(GL_CCW)
glEnable(GL_LIGHTING)
# Setup light 0
glLightModelfv(GL_LIGHT_MODEL_AMBIENT,ambientLight)
glLightfv(GL_LIGHT0,GL_AMBIENT,ambientLight)
glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuseLight)
glLightfv(GL_LIGHT0,GL_SPECULAR,specular)
# Position and turn on the light
glLightfv(GL_LIGHT0,GL_POSITION,lightPos)
glEnable(GL_LIGHT0)
# Enable color tracking
glEnable(GL_COLOR_MATERIAL)
# Set Material properties to follow glColor values
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE)
# All materials hereafter have full specular reflectivity with a moderate shine
glMaterialfv(GL_FRONT, GL_SPECULAR,specref)
glMateriali(GL_FRONT,GL_SHININESS,64)
glClearColor(0.0, 0.0, 0.0, 1.0) #背景黑色
#改变窗口大小时调用
def ChangeSize(w,h):
nRange = 100.0
if(h == 0): #防止除数为0
h = 1
glViewport(0, 0, w, h) #设置视区大小
glMatrixMode(GL_PROJECTION) #投影矩阵模式
glLoadIdentity() #矩阵堆栈清空
#设置裁剪窗口大小
if (w <= h):
glOrtho (-nRange, nRange, -nRange*h/w, nRange*h/w, -nRange*2.0, nRange*2.0)
else:
glOrtho (-nRange*w/h, nRange*w/h, -nRange, nRange, -nRange*2.0, nRange*2.0)
glMatrixMode(GL_MODELVIEW) #模型矩阵模式
glLoadIdentity()
def SpecialKeys(key,x,y):
global xRot,yRot
if(key == GLUT_KEY_UP):
xRot-= 5.0
if(key == GLUT_KEY_DOWN):
xRot += 5.0
if(key == GLUT_KEY_LEFT):
yRot -= 5.0
if(key == GLUT_KEY_RIGHT):
yRot += 5.0
if(key > 356.0):
xRot = 0.0
if(key < -1.0):
xRot = 355.0
if(key > 356.0):
yRot = 0.0
if(key < -1.0):
yRot = 355.0
glutPostRedisplay()
xRot=0.0
yRot=0.0
print("三维螺钉,按箭头键改变视角!")
#使用glut初始化OpenGL
glutInit()
glutInitWindowSize(700,700)
#设置显示模式;(注意双缓冲)
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB| GLUT_DEPTH)
glutCreateWindow("Completed Bolt")
glutReshapeFunc(ChangeSize)
glutSpecialFunc(SpecialKeys) #注册键盘回调函数
#调用函数绘制图像
glutDisplayFunc(RenderScene)
SetupRC()
#主循环
glutMainLoop()
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