diff --git a/assets/shaders/ray.frag b/assets/shaders/ray.frag
index 334e4ab..bc106b5 100644
--- a/assets/shaders/ray.frag
+++ b/assets/shaders/ray.frag
@@ -10,12 +10,24 @@ layout (set = 0, binding = 0) uniform Matrices {
 layout (location = 0) in vec2 pos;
 layout (location = 0) out vec4 fragColor;
 
-float sphere(vec3 p, vec3 center, float r) {
-	return length(p-center) - r;
+float opUnion(float v1, float v2) {
+	return min(v1, v2);
+}
+
+float box(vec3 p, vec3 c, vec3 r) {
+	p -= c;
+	vec3 q = abs(p) - r;
+	return length(max(q,0.0)) + min(max(q.x, max(q.y,q.z)), 0.0);
+}
+
+float sphere(vec3 p, vec3 c, float r) {
+	return length(p-c) - r;
 }
 
 float sdf(vec3 pos) {
-	return sphere(pos, vec3(0.0, 0.0, 0.0), 3.0);
+	float d = sphere(pos, vec3(0.0, 0.0, 0.0), 3.0);
+	d = opUnion(d, box(pos, vec3(0.0, -10.0, 0.0), vec3(10.0, 1.0, 10.0)));
+	return d;
 }
 
 float raycast(vec3 dir) {
@@ -23,13 +35,13 @@ float raycast(vec3 dir) {
 	for(int i = 0; i < 64; i++) {
 		float dt = sdf(cam_pos + dir * t);
 		if(dt < 0.0001*t)
-			return float(i) / 64.0;
+			return t;
 		else if(dt > 200.0)
-			return 1.0;
+			return -1.0;
 		t += dt;
 	}
 
-	return 1.0;
+	return -1.0;
 }
 
 vec3 raygen() {
@@ -43,6 +55,10 @@ vec3 raygen() {
 void main() {
 	vec3 dir = raygen();
 	float d = raycast(dir);
+	vec3 point = cam_pos + dir * d;
 
-	fragColor = vec4(d);
+	if(d < 0.0)
+		fragColor = vec4(0.0);
+	else
+		fragColor = vec4(mod(point.y, 1.0));
 }
\ No newline at end of file
diff --git a/assets/shaders/ray.frag.spv b/assets/shaders/ray.frag.spv
index b44de57..1bb15e8 100644
Binary files a/assets/shaders/ray.frag.spv and b/assets/shaders/ray.frag.spv differ
diff --git a/assets/shaders/test b/assets/shaders/test
new file mode 100644
index 0000000..e69de29