qt-everywhere-src-5.15.1/qtgraphicaleffects/src/effects/shaders/opacitymask_invert.frag

varying highp vec2 qt_TexCoord0;
uniform highp float qt_Opacity;
uniform lowp sampler2D source;
uniform lowp sampler2D maskSource;
void main(void) {
    gl_FragColor = texture2D(source, qt_TexCoord0.st) * (1.0 - texture2D(maskSource, qt_TexCoord0.st).a) * qt_Opacity;
}