Renaming the shaders again, because the extensions I gave them were confusing GitHub's syntax highlighting.

shaders/stripePass.frag.glsl

@@ -0,0 +1,27 @@
+precision mediump float;
+#define PI 3.14159265359
+
+uniform sampler2D tex;
+uniform sampler2D bloomTex;
+uniform sampler2D stripes;
+uniform float ditherMagnitude;
+uniform float time;
+uniform vec3 backgroundColor;
+varying vec2 vUV;
+
+highp float rand( const in vec2 uv, const in float t ) {
+	const highp float a = 12.9898, b = 78.233, c = 43758.5453;
+	highp float dt = dot( uv.xy, vec2( a,b ) ), sn = mod( dt, PI );
+	return fract(sin(sn) * c + t);
+}
+
+void main() {
+	vec3 color = texture2D(stripes, vUV).rgb;
+	// Combine the texture and bloom
+	float brightness = min(1., texture2D(tex, vUV).r * 2.) + texture2D(bloomTex, vUV).r;
+
+	// Dither: subtract a random value from the brightness
+	brightness = brightness - rand( gl_FragCoord.xy, time ) * ditherMagnitude;
+	
+	gl_FragColor = vec4(color * brightness + backgroundColor, 1.0);
+}