start of second test generator. revealed issue with neighbor linkage overwriting

shaders/rt_quad.frag

@@ -377,7 +377,7 @@ vec3 get_lighting_color(uint volume_start, vec3 starting_pos, vec4 orig_color_sa
     uint light_num = 0;
 
     // initialize color
-    vec3 color_sum = vec3(0.0, 0.0, 0.0);// + (orig_color_sample.xyz * 0.01);
+    vec3 color_sum = vec3(0.0, 0.0, 0.0) + (orig_color_sample.xyz * 0.01);
 
     uint max_iterations = max_num_lights * max_iterations_per_light;
     uint iteration = 0;