OpenGL和glfw在python中创建后调整窗口大小

Question

在python3中，我使用glfw和PyOpenGL。当我创建一个隐藏的窗口，渲染到它，读取它的像素-我得到了很好的渲染图像。在

如果我试图调整窗口大小-OpenGL似乎不知道新的渲染大小，而是将大图像渲染到一个小窗口中，这会使回读图像被裁剪

下面是一个例子：

width = height = 500

# Create the hidden window we are going to render into
glfw.window_hint(glfw.VISIBLE, False)
glfw.window_hint(glfw.CONTEXT_VERSION_MAJOR, 3)
glfw.window_hint(glfw.CONTEXT_VERSION_MINOR, 2)
glfw.window_hint(glfw.OPENGL_FORWARD_COMPAT, OpenGL.GL.GL_TRUE)
glfw.window_hint(glfw.OPENGL_PROFILE, glfw.OPENGL_CORE_PROFILE)
window = glfw.create_window(width, height, "hidden window", None, None)
assert window
glfw.make_context_current(window)

# THIS CODE BREAKS IT:
# width = height = 300
# glfw.set_window_size(window, 300, 300)

# render into the window:
# ...code to choose the VBO...
glDrawArrays(GL_TRIANGLES, ...)


# Read back the created pixels:
data = glReadPixels(0, 0, width, height, OpenGL.GL.GL_RGB, OpenGL.GL.GL_UNSIGNED_BYTE)
rendered_image =  np.frombuffer(data, dtype=np.uint8).reshape(rendered_image_height, rendered_image_width, 3)[::-1]

另一种在创建窗口并对其进行多次渲染（并明显清除）后更改渲染大小的另一种解决方案可能也很有用

Answer 1

当窗口的大小发生变化时，必须通过^{}重置视口矩形

实现resize回调并按^{}设置：

vp_size_changed = False
def resize_cb(window, w, h):
    global vp_size_changed
    vp_size_changed = True

^{pr2}$

通过^{}获得新的帧缓冲区大小，并通过^{}设置视口矩形：

global vp_size_changed

while not glfw.window_should_close(window):
    glfw.poll_events()

    if vp_size_changed:
        vp_size_changed = False
        w, h = glfw.get_framebuffer_size(window)
        glViewport(0, 0, w, h)
        print("new viewport size:", w, h)