process all X11 event waiting in the queue in the same cycle
avoid so called glitches after continuous key press or X11 tunelled through SSH
#version 330 core
uniform sampler2D uTexture;
in vec2 vTextureXY;
out vec4 fColor;
void main() {
fColor = texture(uTexture, vTextureXY).rgba;
float lineCount = 200.;
fColor.xyz *= abs(sin(radians(vTextureXY.y * 180. * lineCount)));
}