Overlay works perfectly with multiple running at once

colorkey.frag

@@ -0,0 +1,24 @@
+#version 440
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    vec4 bgcol;
+    bool key_enabled;
+};
+layout(binding = 1) uniform sampler2D source;
+void main() {
+    vec4 p = texture(source, qt_TexCoord0);
+    if (
+        key_enabled    &&
+        p.r == bgcol.r &&
+        p.g == bgcol.g &&
+        p.b == bgcol.b
+    ) {
+        fragColor = vec4(0, 0, 0, 0);
+    }
+    else {
+        fragColor = p;
+    }
+}