Added corruption shader

game/shaders/glitch.gdshader

@@ -0,0 +1,22 @@
+shader_type canvas_item;
+
+uniform float corruption_x = 0.0;
+uniform float edge_width = 50.0;
+uniform mat4 screen_to_world;
+
+uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_nearest_mipmap;
+
+void fragment() {
+	vec4 screen_color = texture(SCREEN_TEXTURE, SCREEN_UV);
+
+	float gray = dot(screen_color.rgb, vec3(0.299, 0.587, 0.114));
+	vec3 bw = vec3(gray);
+
+	vec4 world_pos = screen_to_world * vec4(FRAGCOORD.xy, 0.0, 1.0);
+
+	float dist = world_pos.x - corruption_x;
+	float t = smoothstep(-edge_width, edge_width, dist);
+
+	COLOR.rgb = mix(bw, screen_color.rgb, t);
+	COLOR.a = screen_color.a;
+}