diff --git a/extra/Screenshot_20230414_163233.png b/extra/Screenshot_20230414_163233.png
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diff --git a/extra/example-scene.blend b/extra/example-scene.blend
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diff --git a/extra/example-scene.blend1 b/extra/example-scene.blend1
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index 0000000..91bfdec
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diff --git a/extra/reference.png b/extra/reference.png
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diff --git a/src/shader/pathtracing/bsdf.glsl b/src/shader/pathtracing/bsdf.glsl
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/src/shader/pathtracing/bsdf.glsl
@@ -0,0 +1 @@
+
diff --git a/src/shader/pathtracing/pathtracer.comp b/src/shader/pathtracing/pathtracer.comp
index 47dafd5..523f212 100644
--- a/src/shader/pathtracing/pathtracer.comp
+++ b/src/shader/pathtracing/pathtracer.comp
@@ -3,6 +3,7 @@
 #include "rand/random.glsl"
 #include "raytracing/raytracing.glsl"
 #include "raytracing/camera.glsl"
+#include "bsdf.glsl"
 
 layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
 
@@ -32,8 +33,8 @@ vec3 project(in vec3 a, in vec3 b) {
 void construct_orthonormal_basis(in vec3 up, out vec3 u, out vec3 v, out vec3 w) {
     u = normalize(up);
 
-    vec3 n2 = vec3(1) - u;
-    vec3 n3 = vec3(1) - u.zxy;
+    vec3 n2 = normalize(cross(up, vec3(0, 1.0, 1.0)));
+    vec3 n3 = cross(u, n2);
 
     vec3 w2 = normalize(n2 - (project(u, n2)));
     vec3 w3 = normalize(n3 - project(u, n3) - project(w2, n3));
@@ -64,6 +65,28 @@ vec3 generate_diffuse_ray_direction(in vec3 nor) {
     return normalize(u * hemisphere.x + v * hemisphere.y + w * hemisphere.z);
 }
 
+vec3 trace_direct(in Ray direct_ray) {
+    Hit hit = intersect_scene(direct_ray);
+
+    if (hit.depth < direct_ray.far) {
+
+        Ray ray;
+        ray.origin = direct_ray.origin + direct_ray.direction * hit.depth;
+        ray.direction = generate_diffuse_ray_direction(hit.nor);
+        ray.near = 1e-3;
+        ray.far = 1.0;
+
+        Hit hit = intersect_scene(ray);
+        if (hit.depth == 1.0) {
+            return vec3(1);
+        }
+
+        return vec3(0);
+    }
+
+    return vec3(0);
+}
+
 void main() {
     init_random_state(floatBitsToInt(program_metadata.seconds));
 
@@ -71,23 +94,7 @@ void main() {
 
     Ray camera_ray = construct_camera_ray_pinhole(uv);
 
-    vec3 color = vec3(0);
-
-    Hit result = intersect_scene(camera_ray);
-
-    if (result.depth < camera_ray.far) {
-        Ray ao;
-        ao.origin = camera_ray.origin + camera_ray.direction * result.depth;
-        ao.direction = generate_diffuse_ray_direction(result.nor);
-        ao.near = 1e-3;
-        ao.far = 1e3;
-
-        Hit r2 = intersect_scene(ao);
-
-        if (r2.depth > 1.0) {
-            color = vec3(1);
-        }
-    }
+    vec3 color = trace_direct(camera_ray);
 
     // index of the current pixel as array index
     uint pixel_index = get_pixel_index();
diff --git a/src/shader/pathtracing/raytracing/raytracing.glsl b/src/shader/pathtracing/raytracing/raytracing.glsl
index ebef48c..79fd175 100644
--- a/src/shader/pathtracing/raytracing/raytracing.glsl
+++ b/src/shader/pathtracing/raytracing/raytracing.glsl
@@ -54,7 +54,7 @@ Hit intersect_scene(in Ray ray) {
         if (result.x > ray.near && result.x < hit.depth) {
             hit.uv = result.yz;
             hit.depth = result.x;
-            hit.nor = n;
+            hit.nor = normalize(n);
         }
     }