Add lock and stuff

trifade.frag

@@ -4,11 +4,12 @@ layout(location = 0) out vec4 fragColor;
 layout(std140, binding = 0) uniform buf {
     mat4 qt_Matrix;
     float qt_Opacity;
+    bool fadeDirection; // true: fade top, false: fade bottom
 };
 layout(binding = 1) uniform sampler2D src;
 layout(binding = 2) uniform sampler2D mask;
 void main() {
     vec4 tex = texture(src, coord);
-    float a = texture(mask, coord).a * tex.a * (1-coord.y);
+    float a = texture(mask, coord).a * tex.a * (fadeDirection ? coord.y : 1-coord.y);
     fragColor = vec4(tex.r * a, tex.g * a, tex.b * a, a);
 }