3

我正在尝试使用 pyopengl 自学 OpenGL，我对尝试渲染以原点为中心的简单 2D 正方形感到震惊。每当我将数组值设置为大于或等于 1 时，形状就会占据整个屏幕，就好像我只查看轴的一小部分一样。我试图以用 pyopengl 重写的 NeHe 教程为基础，但我找不到我做错了什么。

from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *

def display():
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

    glBegin(GL_QUADS)
    glVertex3f(2,-2,0)
    glVertex3f(2,2,0)
    glVertex3f(-2,2,0)
    glVertex3f(-2,-2,0)
    glEnd()

    glutSwapBuffers()

if __name__ == '__main__':
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
    glutInitWindowSize(640,480)
    glutCreateWindow("Hello World :'D")

    glutDisplayFunc(display)
    glutIdleFunc(display)
    glutMainLoop()
4

2 回答 2

3

您需要设置投影矩阵和视口。Python 允许我们使用一点函数式编程来以理智的方式做到这一点：

from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *

def display(w, h):
    aspect = float(w)/float(h)
    glViewport(0, 0, w, h)
    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    glOrtho(-aspect * 5, aspect * 5, -5, 5, -1, 1)

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity()

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

    glBegin(GL_QUADS)
    glVertex3f(2,-2,0)
    glVertex3f(2,2,0)
    glVertex3f(-2,2,0)
    glVertex3f(-2,-2,0)
    glEnd()

    glutSwapBuffers()

def reshape(w, h):
    glutDisplayFunc(lambda: display(w, h))
    glutPostRedisplay();

if __name__ == '__main__':
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH)
    glutInitWindowSize(640,480)
    glutCreateWindow("Hello World :'D")

    glutReshapeFunc(reshape)
    glutIdleFunc(glutPostRedisplay)
    glutMainLoop()
于 2011-06-16T21:13:16.877 回答
0

尝试设置一个非默认的投影矩阵：

def display():
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

    glMatrixMode(GL_PROJECTION)
    glLoadIdentity()
    glOrtho( 0, 640, 0, 480, -10, 10)
    glMatrixMode(GL_MODELVIEW)
    glLoadIdentity()

    ...
于 2011-06-16T21:06:32.280 回答