使用Python渲染OpenGL的.obj和.mtl文件
安装：
安装python，略。
安装pip，略。
安装其他库：
DOS> pip install pygame
DOS> pip install PyOpenGL
DOS> pip install numpy
DOS> pip install trimesh
DOS> pip install “pyglet<2”
DOS> pip install scipy
使用：
view.py：
# Basic OBJ file viewer. needs objloader from:
# LMB + move: rotate
# RMB + move: pan
# Scroll wheel: zoom in/out
import sys, pygame
from pygame.locals import *
from pygame.constants import *
from OpenGL.GL import *
from OpenGL.GLU import *
# IMPORT OBJECT LOADER
from objloader import *
pygame.init()
viewport = (800,600)
hx = viewport[0]/2
hy = viewport[1]/2
srf = pygame.display.set_mode(viewport, OPENGL | DOUBLEBUF)
glLightfv(GL_LIGHT0, GL_POSITION, (-40, 200, 100, 0.0))
glLightfv(GL_LIGHT0, GL_AMBIENT, (0.2, 0.2, 0.2, 1.0))
glLightfv(GL_LIGHT0, GL_DIFFUSE, (0.5, 0.5, 0.5, 1.0))
glEnable(GL_LIGHT0)
glEnable(GL_LIGHTING)
glEnable(GL_COLOR_MATERIAL)
glEnable(GL_DEPTH_TEST)
glShadeModel(GL_SMOOTH) # most obj files expect to be smooth-shaded
# LOAD OBJECT AFTER PYGAME INIT
obj = OBJ(sys.argv[1], swapyz=True)
clock = pygame.time.Clock()
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
width, height = viewport
gluPerspective(90.0, width/float(height), 1, 100.0)
glEnable(GL_DEPTH_TEST)
glMatrixMode(GL_MODELVIEW)
rx, ry = (0,0)
tx, ty = (0,0)
zpos = 5
rotate = move = False
while 1:
clock.tick(30)
for e in pygame.event.get():
if e.type == QUIT:
sys.exit()
elif e.type == KEYDOWN and e.key == K_ESCAPE:
sys.exit()
elif e.type == MOUSEBUTTONDOWN:
if e.button == 4: zpos = max(1, zpos-1)
elif e.button == 5: zpos += 1
elif e.button == 1: rotate = True
elif e.button == 3: move = True
elif e.type == MOUSEBUTTONUP:
if e.button == 1: rotate = False
elif e.button == 3: move = False
elif e.type == MOUSEMOTION:
i, j = e.rel
if rotate:
rx += i
ry += j
if move:
tx += i
ty -= j
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glLoadIdentity()
# RENDER OBJECT
glTranslate(tx/20., ty/20., – zpos)
glRotate(ry, 1, 0, 0)
glRotate(rx, 0, 1, 0)
glCallList(obj.gl_list)
pygame.display.flip()
objloader.py：
import numpy
import pygame
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *
def MTL(filename):
contents = {}
mtl = None
for line in open(filename, “r”):
if line.startswith(‘#’): continue
values = line.split()
if not values: continue
if values[0] == ‘newmtl’:
mtl = contents[values[1]] = {}
elif mtl is None:
raise (ValueError, “mtl file doesn’t start with newmtl stmt”)
elif values[0] == ‘map_Kd’:
# load the texture referred to by this declaration
mtl[values[0]] = values[1]
print(mtl[‘map_Kd’])
surf = pygame.image.load(mtl[‘map_Kd’])
image = pygame.image.tostring(surf, ‘RGBA’, 1)
ix, iy = surf.get_rect().size
texid = mtl[‘texture_Kd’] = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texid)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_LINEAR)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, ix, iy, 0, GL_RGBA,
GL_UNSIGNED_BYTE, image)
else:
mtl[values[0]] = map(float, values[1:])
return contents
class OBJ:
def __init__(self, filename, swapyz=False):
“””Loads a Wavefront OBJ file. “””
self.vertices = []
self.normals = []
self.texcoords = []
self.faces = []
material = None
for line in open(filename, “r”):
if line.startswith(‘#’): continue
values = line.split()
if not values: continue
if values[0] == ‘v’:
# v = map(float, values[1:4])
v = list(map(float, values[1:4]))
if swapyz:
v = v[0], v[2], v[1]
self.vertices.append(v)
elif values[0] == ‘vn’:
# v = map(float, values[1:4])
v = list(map(float, values[1:4]))
if swapyz:
v = v[0], v[2], v[1]
self.normals.append(v)
elif values[0] == ‘vt’:
# self.texcoords.append(map(float, values[1:3]))
self.texcoords.append(list(map(float, values[1:3])))
elif values[0] in (‘usemtl’, ‘usemat’):
material = values[1]
elif values[0] == ‘mtllib’:
self.mtl = MTL(values[1])
elif values[0] == ‘f’:
face = []
texcoords = []
norms = []
for v in values[1:]:
w = v.split(‘/’)
face.append(int(w[0]))
if len(w) >= 2 and len(w[1]) > 0:
texcoords.append(int(w[1]))
else:
texcoords.append(0)
if len(w) >= 3 and len(w[2]) > 0:
norms.append(int(w[2]))
else:
norms.append(0)
self.faces.append((face, norms, texcoords, material))
self.gl_list = glGenLists(1)
glNewList(self.gl_list, GL_COMPILE)
glEnable(GL_TEXTURE_2D)
glFrontFace(GL_CCW)
for face in self.faces:
vertices, normals, texture_coords, material = face
mtl = self.mtl[material]
if ‘texture_Kd’ in mtl:
# use diffuse texmap
glBindTexture(GL_TEXTURE_2D, mtl[‘texture_Kd’])
else:
# just use diffuse colour
tmpList = list(mtl[‘Kd’])
listLen = len(tmpList)
if listLen == 1:
glColor(tmpList[0])
elif listLen == 2:
glColor(tmpList[0], tmpList[1])
elif listLen == 3:
glColor(tmpList[0], tmpList[1], tmpList[2])
elif listLen == 4:
glColor(tmpList[0], tmpList[1], tmpList[2], tmpList[3])
#glColor(*mtl[‘Kd’])
glBegin(GL_POLYGON)
for i in range(len(vertices)):
if normals[i] > 0:
glNormal3fv(self.normals[normals[i] – 1])
if texture_coords[i] > 0:
glTexCoord2fv(self.texcoords[texture_coords[i] – 1])
glVertex3fv(self.vertices[vertices[i] – 1])
glEnd()
glDisable(GL_TEXTURE_2D)
glEndList()
运行：
需要把上面两个源文件和.obj、.mtl、.png等资源文件放到一个目录下：
DOS> python view.py uploads_files_3746622_FK8.obj
（obj文件里面含有需要的mtl文件名，mtl文件里面含有需要的.png等其他资源文件名）