pyglet window.flip() 不更新

Question

我正在用 pyglet 画一个圆圈和一些文字。我希望它在按键后更新，但在第二次调用 window.flip() 时，窗口只是空的。任何建议表示赞赏。

from math import *
from pyglet.gl import *

window = pyglet.window.Window()


def make_circle(x_pos, y_pos, radius, numPoints):
    verts = []

    glMatrixMode(GL_PROJECTION)
    glOrtho(0, 640, 0, 480, -1, 1)
    glMatrixMode(GL_MODELVIEW)

    glClear(pyglet.gl.GL_COLOR_BUFFER_BIT)
    glColor3f(1, 1, 0)
    for i in range(numPoints):
        angle = radians(float(i) / numPoints * 360.0)
        x = radius * cos(angle) + x_pos
        y = radius * sin(angle) + y_pos
        verts += [x, y]
    circle = pyglet.graphics.vertex_list(numPoints, ('v2f', verts))
    circle.draw(GL_LINE_LOOP)


def text(x, y, text):
    label = pyglet.text.Label(text, font_size=36,
                              x=x, y=y, anchor_x='left', anchor_y='bottom',
                              color=(255, 123, 255, 255))
    label.draw()


make_circle(5, 5, 100, 10)
text(10, 10, 'Test1')
text(30, 30, 'Text2')

window.flip()
input()

make_circle(5, 5, 22, 10)
text(23, 10, 'This text does not appear')
text(30, 23, 'Neither does this one')
window.flip()
input()

Answer 1

如果您不使用默认事件循环，那么您必须自己执行事件循环的步骤。打电话给window.flip()是不够的。
在绘图之前，您必须调用 pyglet.clock.tick() 来表示一帧已经过去，并调用 window.dispatch_events() 来轮询操作系统事件队列中的新事件并调用附加的事件处理程序。
请注意，由于事件是手动调度的，因此无需设置投影矩阵。

另见Dispatching events manually

例如：

from math import *
from pyglet.gl import *

def make_circle(x_pos, y_pos, radius, numPoints):
    verts = []

    glClear(pyglet.gl.GL_COLOR_BUFFER_BIT)
    glColor3f(1, 1, 0)
    for i in range(numPoints):
        angle = radians(float(i) / numPoints * 360.0)
        x = radius * cos(angle) + x_pos
        y = radius * sin(angle) + y_pos
        verts += [x, y]
    circle = pyglet.graphics.vertex_list(numPoints, ('v2f', verts))
    circle.draw(GL_LINE_LOOP)


def text(x, y, text):
    label = pyglet.text.Label(text, font_size=36,
                              x=x, y=y, anchor_x='left', anchor_y='bottom',
                              color=(255, 123, 255, 255))
    label.draw()

window = pyglet.window.Window()
# make OpenGL context current
window.switch_to()

# signify that one frame has passed
pyglet.clock.tick()
# poll the operating system event queue
window.dispatch_events()

make_circle(5, 5, 100, 10)
text(10, 10, 'Test1')
text(30, 30, 'Text2')

# swap buffers
window.flip()

input()

# signify that one frame has passed
pyglet.clock.tick()
# poll the operating system event queue
window.dispatch_events()

make_circle(5, 5, 22, 10)
text(23, 10, 'This text does not appear')
text(30, 23, 'Neither does this one')

# swap buffers
window.flip()

input()