Triangles fade from bottom and behave better on antialiased mask edges

trifade.frag

@@ -0,0 +1,14 @@
+#version 440
+layout(location = 0) in vec2 coord;
+layout(location = 0) out vec4 fragColor;
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+};
+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);
+    fragColor = vec4(tex.r * a, tex.g * a, tex.b * a, a);
+}