Объект экспорта OpenGL как .png

Question

Я искал решение для всех форумов, но я не нашел решения для этого. Что я хочу сделать, так это то, что когда я нажму кнопку ввода, он будет экспортировать мой объект как 2D-изображение в формате .png с прозрачным фоном. Объект отображается в окне Pygame с возможностью вращать и перемещать его с помощью мыши. Так, например, я хочу вращать и перемещать загруженный 3D-объект, и после нажатия Enter я хочу экспортировать как .png.

Код:

    # Basic OBJ file viewer. needs objloader from:
#  http://www.pygame.org/wiki/OBJFileLoader
# 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 *
from OpenGL import GL
import numpy as np

# IMPORT OBJECT LOADER
from objloader import *
import cv2

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("mask/surgical_mask_2.obj", swapyz=True)
print(obj)

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:
            buffer = (GL.GLubyte * (3 * 800 * 600))(0)
            img = GL.glReadPixels(0, 0, 800, 600, GL.GL_BGR, GL.GL_UNSIGNED_BYTE, buffer)
            img = np.array(img)
            cv2.imshow("Output", img)

            k = cv2.waitKey(5) & 0xFF
            if k == 27:
                break
        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()

Класс OBJLoader:

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]] = [float(v) for v in 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 = [float(v) for v in values[1:4]]
                if swapyz:
                    v = v[0], v[2], v[1]
                self.vertices.append(v)
            elif values[0] == 'vn':
                v = [float(v) for v in values[1:4]]
                if swapyz:
                    v = v[0], v[2], v[1]
                self.normals.append(v)
            elif values[0] == 'vt':
                self.texcoords.append([float(v) for v in 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
                glColor3f(*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()

Спасибо за ваши ответы!