Window resize is laggy and doesn't resize viewport

[gtimoshaz]

Probably a revival of this one, which seems to be closed as solved

The code below starts a window, and it works fine in 60+ FPS, but if I try to resize the window, everything lags and the viewport is not resized.

Screencast.from.04.11.2023.00.41.47.webm

I use Ubuntu 22.04.3 LTS, with proprietary nVidia drivers on X11. moderngl and moderngl-window are installed from pypi inside a clean conda environment.

Expected result:

The resize should be smooth, and the viewport should match the window

Actual result:

The resize is laggy and the viewport size doesn't follow the window size

Here is the output of the program at the start:

2023-11-04 00:41:39,876 - moderngl_window - INFO - Attempting to load window class: moderngl_window.context.pyglet.Window
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - Context Version:
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - ModernGL: 5.8.2
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - vendor: NVIDIA Corporation
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - renderer: NVIDIA GeForce MX130/PCIe/SSE2
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - version: 3.3.0 NVIDIA 535.129.03
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - python: 3.10.12 (main, Jun 11 2023, 05:26:28) [GCC 11.4.0]
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - platform: linux
2023-11-04 00:41:40,027 - moderngl_window.context.base.window - INFO - code: 330

Here is the code:

import moderngl
import moderngl_window as mglw
import numpy as np


fragment_shader = '''
#version 330

out vec4 color;
uniform float time;

void main() {
    color = vec4(gl_FragCoord.x / 4000.0, gl_FragCoord.y / 4000.0, sin(time) / 2 + 0.5, 1.0);
}
'''

vertex_shader = '''
#version 330

in vec2 vertex_xy;

void main() {
    gl_Position = vec4(vertex_xy, 0.0, 1.0);
}
'''


class App(mglw.WindowConfig):
    gl_version = (3, 3)
    resizable = True

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.prog = self.ctx.program(vertex_shader=vertex_shader, fragment_shader=fragment_shader)
        vertices = np.array([-1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0], dtype='f4')

        self.vbo = self.ctx.buffer(vertices.astype('f4'))
        self.vao = self.ctx.vertex_array(self.prog, [
                (self.vbo, '2f', 'vertex_xy')
            ])

    def render(self, time, frametime):
        self.ctx.clear(time % 1.0, 1.0, 1.0)
        uniform = self.prog["time"]
        uniform.value = time
        self.vao.render(mode=moderngl.TRIANGLE_STRIP)


App.run()

[einarf]

Try adding aspect_ratio = None

class App(mglw.WindowConfig):
    gl_version = (3, 3)
    resizable = True
    aspect_ratio = None

By default we try to respect the aspect ratio for the initial resolution. Possibly there is a scissor box being set causing only a partial screen clear.