OpenGL渲染视图，在python中没有可见的窗口 [英] OpenGL render view without a visible window in python

问题描述

我需要渲染一些场景.我设法使用pyopengl和pygame在python中做到了.问题在于它会在很短的时间内创建一个窗口.

I need to render some scene. I managed to do it in python using pyopengl and pygame. The problem is that it creates a window for a short period of time.

我想渲染相同的图像并保存它，而不创建可见的窗口(或者可能根本不创建窗口，甚至没有pygame).

I want to render the same image and save it, without creating a visible window (Or possibly without creating a window at all, and even without pygame).

import cv2
import numpy as np
import pygame
from pygame.locals import *
from OpenGL.GL import *
from OpenGL.GLU import *

def main():
    DISPLAY_WIDTH = 900
    DISPLAY_HEIGHT = 900

    pygame.init()
    pygame.display.set_mode((DISPLAY_WIDTH, DISPLAY_HEIGHT), DOUBLEBUF | OPENGL)
    gluPerspective(90, (DISPLAY_WIDTH / DISPLAY_HEIGHT), 0.01, 12)

    glEnable(GL_TEXTURE_2D)
    glEnable(GL_DEPTH_TEST)
    glDepthFunc(GL_LEQUAL)

    glRotatef(-90, 1, 0, 0) # Straight rotation
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glRotatef(285, 0, 0, 1) # Rotate yaw
    glTranslatef(-5, -3, -2) # Move to position

    # Draw rectangle
    glBegin(GL_QUADS)
    glColor3f(1, 0, 0)
    glVertex3f(2, 2, 0)
    glVertex3f(2, 2, 2)
    glVertex3f(2, 6, 2)
    glVertex3f(2, 6, 0)
    glEnd()

    image_buffer = glReadPixels(0, 0, DISPLAY_WIDTH, DISPLAY_HEIGHT, OpenGL.GL.GL_RGB, OpenGL.GL.GL_UNSIGNED_BYTE)
    image = np.frombuffer(image_buffer, dtype=np.uint8).reshape(DISPLAY_WIDTH, DISPLAY_HEIGHT, 3)

    cv2.imwrite(r"C:\temp\image.png", image)

    pygame.quit()


if __name__ == "__main__":
    main()

推荐答案

我想渲染相同的图像并保存它，而不创建可见的窗口

I want to render the same image and save it, without creating a visible window

无法创建版本大于1.0的 OpenGL上下文窗口.
请参阅问题的答案在没有窗口的情况下创建OpenGL上下文.

It is not possible to create an OpenGL Context with an version above 1.0 without any window.
See the answer to the question Creating OpenGL context without window.

但是可以使用完全隐藏的窗口进行屏幕外"渲染.

遗憾的是，无法使用 Pygame 创建最初隐藏的窗口.
. 另请参见隐藏pygame显示.

But it is possible to use a completely hidden window for "offscreen" rendering.

Sadly it is not possible to create a initially hidden window with Pygame.
It is only possible to hide a window after it was created by pygame.display.iconify(). See also Hiding pygame display.

但是可以通过设置窗口提示 VISIBLE到False.

But it is possible to create a initially hidden window with the GLFW library by setting the window hint VISIBLE to False.

可以在 glfw 1.7.0 中找到glfw库.

The glfw library can be found at glfw 1.7.0.

代码可能看起来像这样:

The code may look like this:

import cv2
import numpy as np
from OpenGL.GL import *
from OpenGL.GLU import *
import glfw

def main():
    DISPLAY_WIDTH = 900
    DISPLAY_HEIGHT = 900

    # Initialize the library
    if not glfw.init():
        return
    # Set window hint NOT visible
    glfw.window_hint(glfw.VISIBLE, False)
    # Create a windowed mode window and its OpenGL context
    window = glfw.create_window(DISPLAY_WIDTH, DISPLAY_HEIGHT, "hidden window", None, None)
    if not window:
        glfw.terminate()
        return

    # Make the window's context current
    glfw.make_context_current(window)

    gluPerspective(90, (DISPLAY_WIDTH / DISPLAY_HEIGHT), 0.01, 12)

    glEnable(GL_TEXTURE_2D)
    glEnable(GL_DEPTH_TEST)
    glDepthFunc(GL_LEQUAL)

    glRotatef(-90, 1, 0, 0) # Straight rotation
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glRotatef(285, 0, 0, 1) # Rotate yaw
    glTranslatef(-5, -3, -2) # Move to position

    # Draw rectangle
    glBegin(GL_QUADS)
    glColor3f(1, 0, 0)
    glVertex3f(2, 2, 0)
    glVertex3f(2, 2, 2)
    glVertex3f(2, 6, 2)
    glVertex3f(2, 6, 0)
    glEnd()

    image_buffer = glReadPixels(0, 0, DISPLAY_WIDTH, DISPLAY_HEIGHT, OpenGL.GL.GL_RGB, OpenGL.GL.GL_UNSIGNED_BYTE)
    image = np.frombuffer(image_buffer, dtype=np.uint8).reshape(DISPLAY_WIDTH, DISPLAY_HEIGHT, 3)

    cv2.imwrite(r"C:\temp\image.png", image)

    glfw.destroy_window(window)
    glfw.terminate()

if __name__ == "__main__":
    main()

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