add multiple samples per pixel

shader/root/rt.glsl

@@ -78,6 +78,12 @@ void main()
     int bounces = (1-sky) * BOUNCES; 
     pixel.xyz = mix(pixel.xyz, _skyColor, sky);
 
+    // sample
+    int samples = 2;
+    for (int i = 0; i < samples; i++)
+    {
+        float sampleDepth = 0;
+
         // trace the ray's path around the scene
         for (int j = 0; j < bounces; j++)
         {
@@ -90,6 +96,9 @@ void main()
             if (length(ray.energy) < 0.001) break;
         }
 
+        depth += sampleDepth / float(samples);
+    }
+
     pixel.xyz = mix(pixel.xyz, vec3(1.0), depth);
 
     // output to a specific pixel in the image