PyOpenGL sphere with texture

问题

I want to use Python PyOpenGL for generating a scene of three spheres. Two on the side with color (red and green). Middle one with any texture on it (bricks texture which is actually square jpg file in the same directory as code is).

There is what I have done so far:

From some reason texture in the middle sphere generated by gluSphere() has strange behaviour. There are some small green triangles instead of my texture file.

This is my texture file:

I have tried to map this file as surface, e.g. texture on the middle sphere. I don't know where the problem is.

There is my code, I have no idea what I miss or what is wrong to get proper texture mapping on middle sphere:

from OpenGL.GLUT import *
from OpenGL.GLU import *
from OpenGL.GL import *
import sys
from PIL import Image as Image
import numpy

name = 'Navigation paradigm'

def main():
    glutInit(sys.argv)
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
    glutInitWindowSize(800, 800)
    glutInitWindowPosition(350, 200)
    glutCreateWindow(name)
    glClearColor(0., 0., 0., 1.)
    glShadeModel(GL_SMOOTH)
    glEnable(GL_CULL_FACE)
    glEnable(GL_DEPTH_TEST)
    glEnable(GL_LIGHTING)
    lightZeroPosition = [10., 4., 10., 1.]
    lightZeroColor = [0.8, 1.0, 0.8, 1.0]
    glLightfv(GL_LIGHT0, GL_POSITION, lightZeroPosition)
    glLightfv(GL_LIGHT0, GL_DIFFUSE, lightZeroColor)
    glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.1)
    glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05)
    glEnable(GL_LIGHT0)
    glutDisplayFunc(display_scene)
    glMatrixMode(GL_PROJECTION)
    gluPerspective(40., 1., 1., 40.)
    glMatrixMode(GL_MODELVIEW)
    gluLookAt(0, 0, 10,
              0, 0, 0,
              0, 1, 0)
    glPushMatrix()
    glutMainLoop()
    return

def display_scene():
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glPushMatrix()
    # Textured thing 
    tex = read_texture('brick.jpg')
    qobj = gluNewQuadric()
    gluQuadricTexture(qobj, GL_TRUE)
    glEnable(GL_TEXTURE_2D)
    glBindTexture(GL_TEXTURE_2D, tex)
    glBegin(GL_TRIANGLES)
    gluSphere(qobj, 1, 50, 50)
    gluDeleteQuadric(qobj)
    glDisable(GL_TEXTURE_2D)
    # Left sphere
    color = [1.0, 0.0, 0.0, 1.0]
    glMaterialfv(GL_FRONT, GL_DIFFUSE, color)
    glTranslatef(-2, 0, 0)
    glutSolidSphere(1, 100, 20)
    # Right sphere
    color = [0.0, 1.0, 0.0, 1.0]
    glMaterialfv(GL_FRONT, GL_DIFFUSE, color)
    glTranslatef(4, 0, 0)
    glutSolidSphere(1, 100, 20)
    glPopMatrix()
    glutSwapBuffers()
    return

def read_texture(filename):
    img = Image.open(filename)
    img_data = numpy.array(list(img.getdata()), numpy.int8)
    textID = glGenTextures(1)
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL)
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img.size[0], img.size[1], 0, GL_RGB, GL_UNSIGNED_BYTE, img_data)
    return textID

if __name__ == '__main__':
    main()

回答1:

^{I know that this is in relation to your new question. But there is a slightly different "problem" at hand. So just in case someone else has the same problem, I'm going to answer it.}

First of all, as mentioned in the comments you don't need to call glBegin(). Because gluSphere() already manages that. Additionally if you were to call glBegin() you'd also need to call glEnd(). So the reason you're seeing something, is basically because you're confusing your driver, and it then does something it isn't supposed to do.

In read_texture() after you generate a texture name you don't bind it. So the subsequent texture related calls are going to the default texture and not your newly created texture.

textID  = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, textID) # This is what's missing

^{This is equally found in the answer to the newer question.}

After adding the missing glBindTexture() call, you'll get a result looking like this.

Now it might look a bit weird, and it might look like something is wrong. But the fact of the matter is that everything is working as it should. The problem lies with the texture itself.

The "problem" is that your brick texture isn't a spherical mapped texture. If we now just only replace your brick texture with a spherical mapped texture, then well get the following.

Here's the spherical mapped texture used above:

来源：https://stackoverflow.com/questions/42986754/pyopengl-sphere-with-texture