diff --git a/ref/vk/shaders/bounce.comp b/ref/vk/shaders/bounce.comp
index 60b3823a..f40c354b 100644
--- a/ref/vk/shaders/bounce.comp
+++ b/ref/vk/shaders/bounce.comp
@@ -95,92 +95,13 @@ bool getHit(vec3 origin, vec3 direction, inout RayPayloadPrimary payload) {
 }
 const int INDIRECT_SCALE = 2;
 
-#define BRDF_TYPE_NONE 0
-#define BRDF_TYPE_DIFFUSE 1
-#define BRDF_TYPE_SPECULAR 2
-int pickBounceDirection(MaterialProperties material, vec3 view, vec3 geometry_normal, vec3 shading_normal, /*float alpha, */out vec3 out_direction, inout vec3 inout_throughput) {
-#if 1
-	// Idiotic sampling, super noisy, bad distribution, etc etc
-	// But we need to start somewhere
-	const int brdf_type = (rand01() > .5) ? BRDF_TYPE_DIFFUSE : BRDF_TYPE_SPECULAR;
-
-	if (any(isnan(geometry_normal))) {
-		inout_throughput = vec3(1.,0.,1.);
-		return brdf_type;
-	}
-
-	// Very bad distribution, don't do this.
-	out_direction = vec3(rand01(), rand01(), rand01()) * 2. - 1.;
-	out_direction *= sign(dot(out_direction, shading_normal));
-
-	if (dot(out_direction, out_direction) < 1e-5 || dot(out_direction, geometry_normal) <= 0.)
-		return BRDF_TYPE_NONE;
-	//out_direction = reflect(-view, shading_normal);
-	out_direction = normalize(out_direction);
-
-	vec3 diffuse, specular;
-	evalSplitBRDF(shading_normal, out_direction, view, material, diffuse, specular);
-
-	/*
-	if (any(isnan(diffuse))) {
-		inout_throughput = vec3(0., 1., 0.);
-		return brdf_type;
-	}
-	*/
-
-	inout_throughput *= (brdf_type == BRDF_TYPE_DIFFUSE) ? diffuse : specular;
-
-	const float throughput_threshold = 1e-3;
-	if (dot(inout_throughput, inout_throughput) < throughput_threshold)
-		return BRDF_TYPE_NONE;
-
-	// FIXME better sampling
-	return brdf_type;
-#else
-	int brdf_type = BRDF_TYPE_DIFFUSE;
-	// FIXME address translucency properly
-	const float alpha = (base_a.a);
-	if (1. > alpha && rand01() > alpha) {
-		brdf_type = BRDF_TYPE_SPECULAR;
-		// TODO: when not sampling randomly: throughput *= (1. - base_a.a);
-		bounce_direction = normalize(refract(direction, geometry_normal, .95));
-		geometry_normal = -geometry_normal;
-		//throughput /= base_a.rgb;
-	} else {
-		if (material.metalness == 1.0f && material.roughness == 0.0f) {
-			// Fast path for mirrors
-			brdf_type = BRDF_TYPE_SPECULAR;
-		} else {
-			// Decide whether to sample diffuse or specular BRDF (based on Fresnel term)
-			const float brdf_probability = getBrdfProbability(material, -direction, shading_normal);
-			if (rand01() < brdf_probability) {
-				brdf_type = BRDF_TYPE_SPECULAR;
-				throughput /= brdf_probability;
-			}
-		}
-
-		const vec2 u = vec2(rand01(), rand01());
-		vec3 brdf_weight = vec3(0.);
-		if (!evalIndirectCombinedBRDF(u, shading_normal, geometry_normal, -direction, material, brdf_type, bounce_direction, brdf_weight))
-			return false;
-		throughput *= brdf_weight;
-	}
-
-	const float throughput_threshold = 1e-3;
-	if (dot(throughput, throughput) < throughput_threshold)
-		return false;
-
-	return true;
-#endif
-}
-
 struct MaterialEx {
 	MaterialProperties prop;
 	vec3 geometry_normal, shading_normal;
 	//TODO float alpha;
 };
 
-int max_bounces = 2;
+int max_bounces = 1;
 
 void computeBounces(MaterialEx mat, vec3 pos, vec3 direction, inout vec3 diffuse, inout vec3 specular) {
 	const float ray_normal_fudge = .01;
@@ -189,7 +110,9 @@ void computeBounces(MaterialEx mat, vec3 pos, vec3 direction, inout vec3 diffuse
 
 	//const int max_bounces = 2;
 	for (int i = 0; i < max_bounces; ++i) {
-		const int brdf_type = pickBounceDirection(mat.prop, -direction, mat.geometry_normal, mat.shading_normal/* TODO, mat.base_color_a.a*/, bounce_direction, throughput);
+		// TODO blue noise
+		const vec2 rnd = vec2(rand01(), rand01());
+		const int brdf_type = brdfGetSample(rnd, mat.prop, -direction, mat.geometry_normal, mat.shading_normal/* TODO, mat.base_color_a.a*/, bounce_direction, throughput);
 
 		if (brdf_type == BRDF_TYPE_NONE)
 			return;
@@ -248,8 +171,8 @@ void computeBounces(MaterialEx mat, vec3 pos, vec3 direction, inout vec3 diffuse
 			specular += throughput * lighting;
 
 		if (any(isnan(throughput))) {
-			diffuse = vec3(1., 0., 0.);
-			specular = vec3(0., 0., 1.);
+			diffuse = 10.*vec3(1., 0., 0.);
+			specular = 10.*vec3(0., 0., 1.);
 		} else {
 			//diffuse = throughput;
 		}
@@ -300,7 +223,7 @@ void main() {
 		mat.geometry_normal = geometry_normal;
 		mat.shading_normal = shading_normal;
 
-		max_bounces = (pix.x > res.x / 2.) ? 2 : 1;
+		//max_bounces = (pix.x > res.x / 2.) ? 2 : 1;
 
 		computeBounces(mat, pos_t.xyz, direction, diffuse, specular);
 	}
diff --git a/ref/vk/shaders/brdf.glsl b/ref/vk/shaders/brdf.glsl
index 03057ae6..7441a8c4 100644
--- a/ref/vk/shaders/brdf.glsl
+++ b/ref/vk/shaders/brdf.glsl
@@ -69,6 +69,46 @@ float ggxV(float a2, float l_dot_n, float h_dot_l, float n_dot_v, float h_dot_v)
 //  return mix(base, layer, fr)
 //}
 
+void brdfComputeGltfModel(vec3 N, vec3 L, vec3 V, MaterialProperties material, out vec3 out_diffuse, out vec3 out_specular) {
+	const float alpha = material.roughness * material.roughness;
+	const float a2 = alpha * alpha;
+	const vec3 H = normalize(L + V);
+	const float h_dot_v = dot(H, V);
+	const float h_dot_n = dot(H, N);
+	const float l_dot_n = dot(L, N);
+	const float h_dot_l = dot(H, L);
+	const float n_dot_v = dot(N, V);
+
+	/* Original for when the color is known already.
+	const vec3 diffuse_color = mix(material.base_color, vec3(0.), material.metalness);
+	const vec3 f0 = mix(vec3(.04), material.base_color, material.metalness);
+	const vec3 fresnel = f0 + (vec3(1.) - f0) * pow(1. - abs(h_dot_v), 5.);
+	*/
+
+	// Use white for diffuse color here, as compositing happens way later in denoiser/smesitel
+	const vec3 diffuse_color = mix(vec3(1.), vec3(0.), material.metalness);
+
+	// Specular does get the real color, as its contribution is light-direction-dependent
+	const vec3 f0 = mix(vec3(.04), material.base_color, material.metalness);
+	const float fresnel_factor = pow(1. - abs(h_dot_v), 5.);
+	const vec3 fresnel = vec3(1.) * fresnel_factor + f0 * (1. - fresnel_factor);
+
+	// This is taken directly from glTF 2.0 spec. It seems incorrect to me: it should not include the base_color twice.
+	// Note: here diffuse_color doesn't include base_color as it is mixed later, but we can clearly see that
+	// base_color is still visible in the direct_diff term, which it shouldn't be. See E357 ~37:00
+	// TODO make a PR against glTF spec with the correct derivation.
+	//out_diffuse = (vec3(1.) - fresnel) * kOneOverPi * diffuse_color * l_dot_n;
+
+	// This is the correctly derived diffuse term that doesn't include the base_color twice
+	out_diffuse = diffuse_color * kOneOverPi * .96 * (1. - fresnel_factor);
+
+	//if (isnan(l_dot_n))
+	if (any(isnan(N)))
+		out_diffuse = 10.*vec3(1., 1., 0.);
+
+	out_specular = fresnel * ggxD(a2, h_dot_n) * ggxV(a2, l_dot_n, h_dot_l, n_dot_v, h_dot_v);
+}
+
 void evalSplitBRDF(vec3 N, vec3 L, vec3 V, MaterialProperties material, out vec3 out_diffuse, out vec3 out_specular) {
 	out_diffuse = vec3(0.);
 	out_specular = vec3(0.);
@@ -116,43 +156,10 @@ material = f_diffuse + f_specular
 #ifdef BRDF_COMPARE
 if (g_mat_gltf2) {
 #endif
-	const float alpha = material.roughness * material.roughness;
-	const float a2 = alpha * alpha;
-	const vec3 H = normalize(L + V);
-	const float h_dot_v = dot(H, V);
-	const float h_dot_n = dot(H, N);
+	brdfComputeGltfModel(N, L, V, material, out_diffuse, out_specular);
 	const float l_dot_n = dot(L, N);
-	const float h_dot_l = dot(H, L);
-	const float n_dot_v = dot(N, V);
-
-	/* Original for when the color is known already.
-	const vec3 diffuse_color = mix(material.base_color, vec3(0.), material.metalness);
-	const vec3 f0 = mix(vec3(.04), material.base_color, material.metalness);
-	const vec3 fresnel = f0 + (vec3(1.) - f0) * pow(1. - abs(h_dot_v), 5.);
-	*/
-
-	// Use white for diffuse color here, as compositing happens way later in denoiser/smesitel
-	const vec3 diffuse_color = mix(vec3(1.), vec3(0.), material.metalness);
-
-	// Specular does get the real color, as its contribution is light-direction-dependent
-	const vec3 f0 = mix(vec3(.04), material.base_color, material.metalness);
-	const float fresnel_factor = pow(1. - abs(h_dot_v), 5.);
-	const vec3 fresnel = vec3(1.) * fresnel_factor + f0 * (1. - fresnel_factor);
-
-	// This is taken directly from glTF 2.0 spec. It seems incorrect to me: it should not include the base_color twice.
-	// Note: here diffuse_color doesn't include base_color as it is mixed later, but we can clearly see that
-	// base_color is still visible in the direct_diff term, which it shouldn't be. See E357 ~37:00
-	// TODO make a PR against glTF spec with the correct derivation.
-	//out_diffuse = (vec3(1.) - fresnel) * kOneOverPi * diffuse_color * l_dot_n;
-
-	// This is the correctly derived diffuse term that doesn't include the base_color twice
-	out_diffuse = l_dot_n * diffuse_color * kOneOverPi * .96 * (1. - fresnel_factor);
-
-	//if (isnan(l_dot_n))
-	if (any(isnan(N)))
-		out_diffuse = 10.*vec3(1., 1., 0.);
-
-	out_specular = l_dot_n * fresnel * ggxD(a2, h_dot_n) * ggxV(a2, l_dot_n, h_dot_l, n_dot_v, h_dot_v);
+	out_diffuse *= l_dot_n;
+	out_specular *= l_dot_n;
 #ifdef BRDF_COMPARE
 } else {
 	// Prepare data needed for BRDF evaluation - unpack material properties and evaluate commonly used terms (e.g. Fresnel, NdotL, ...)
@@ -177,5 +184,133 @@ if (g_mat_gltf2) {
 #endif
 }
 
+vec3 sampleCosineHemisphereAroundVectorUnnormalized(vec2 rnd, vec3 n) {
+	// Ray Tracing Gems, §16.6.2
+	const float a = 1. - 2. * rnd.x;
+	const float b = sqrt(1. - a * a);
+	const float phi = 2. * kPi * rnd.y;
+
+	// TODO const float pdf = a / kPi;
+	return n + vec3(b * cos(phi), b * sin(phi), a);
+}
+
+// brdf.h
+// Calculates rotation quaternion from input vector to the vector (0, 0, 1)
+// Input vector must be normalized!
+vec4 getRotationToZAxis(vec3 v) {
+	// Handle special case when input is exact or near opposite of (0, 0, 1)
+	if (v.z < -0.99999f) return vec4(1.0f, 0.0f, 0.0f, 0.0f);
+
+	return normalize(vec4(v.y, -v.x, 0.0f, 1.0f + v.z));
+}
+// Returns the quaternion with inverted rotation
+vec4 invertRotation(vec4 q)
+{
+	return vec4(-q.x, -q.y, -q.z, q.w);
+}
+// Optimized point rotation using quaternion
+// Source: https://gamedev.stackexchange.com/questions/28395/rotating-vector3-by-a-quaternion
+vec3 rotatePoint(vec4 q, vec3 v) {
+	const vec3 qAxis = vec3(q.x, q.y, q.z);
+	return 2.0f * dot(qAxis, v) * qAxis + (q.w * q.w - dot(qAxis, qAxis)) * v + 2.0f * q.w * cross(qAxis, v);
+}
+// Samples a direction within a hemisphere oriented along +Z axis with a cosine-weighted distribution
+// Source: "Sampling Transformations Zoo" in Ray Tracing Gems by Shirley et al.
+vec3 sampleHemisphere(vec2 u, out float pdf) {
+	float a = sqrt(u.x);
+	float b = 2. * kPi * u.y;
+
+	vec3 result = vec3(
+		a * cos(b),
+		a * sin(b),
+		sqrt(1.0f - u.x));
+
+	pdf = result.z * kOneOverPi;
+
+	return result;
+}
+vec3 sampleCosineHemisphereAroundVectorUnnormalized2(vec2 rnd, vec3 n) {
+	const vec4 qRotationToZ = getRotationToZAxis(n);
+	float pdf;
+	return rotatePoint(invertRotation(qRotationToZ), sampleHemisphere(rnd, pdf));
+}
+
+#define BRDF_TYPE_NONE 0
+#define BRDF_TYPE_DIFFUSE 1
+#define BRDF_TYPE_SPECULAR 2
+
+int brdfGetSample(vec2 rnd, MaterialProperties material, vec3 view, vec3 geometry_normal, vec3 shading_normal, /*float alpha, */out vec3 out_direction, inout vec3 inout_throughput) {
+#if 1
+	// Idiotic sampling, super noisy, bad distribution, etc etc
+	// But we need to start somewhere
+	// TODO pick diffuse-vs-specular based on expected contribution
+	const int brdf_type = BRDF_TYPE_DIFFUSE;// (rand01() > .5) ? BRDF_TYPE_DIFFUSE : BRDF_TYPE_SPECULAR;
+
+	if (any(isnan(geometry_normal))) {
+		inout_throughput = 10.*vec3(1.,0.,1.);
+		return brdf_type;
+	}
+
+	out_direction = sampleCosineHemisphereAroundVectorUnnormalized2(rnd, shading_normal);
+	if (dot(out_direction, out_direction) < 1e-5 || dot(out_direction, geometry_normal) <= 0.)
+		return BRDF_TYPE_NONE;
+
+	out_direction = normalize(out_direction);
+
+	vec3 diffuse = vec3(0.), specular = vec3(0.);
+	brdfComputeGltfModel(shading_normal, out_direction, view, material, diffuse, specular);
+
+	/*
+	if (any(isnan(diffuse))) {
+		inout_throughput = vec3(0., 1., 0.);
+		return brdf_type;
+	}
+	*/
+
+	inout_throughput *= (brdf_type == BRDF_TYPE_DIFFUSE) ? diffuse : specular;
+
+	const float throughput_threshold = 1e-3;
+	if (dot(inout_throughput, inout_throughput) < throughput_threshold)
+		return BRDF_TYPE_NONE;
+
+	// FIXME better sampling
+	return brdf_type;
+#else
+	int brdf_type = BRDF_TYPE_DIFFUSE;
+	// FIXME address translucency properly
+	const float alpha = (base_a.a);
+	if (1. > alpha && rand01() > alpha) {
+		brdf_type = BRDF_TYPE_SPECULAR;
+		// TODO: when not sampling randomly: throughput *= (1. - base_a.a);
+		bounce_direction = normalize(refract(direction, geometry_normal, .95));
+		geometry_normal = -geometry_normal;
+		//throughput /= base_a.rgb;
+	} else {
+		if (material.metalness == 1.0f && material.roughness == 0.0f) {
+			// Fast path for mirrors
+			brdf_type = BRDF_TYPE_SPECULAR;
+		} else {
+			// Decide whether to sample diffuse or specular BRDF (based on Fresnel term)
+			const float brdf_probability = getBrdfProbability(material, -direction, shading_normal);
+			if (rand01() < brdf_probability) {
+				brdf_type = BRDF_TYPE_SPECULAR;
+				throughput /= brdf_probability;
+			}
+		}
+
+		const vec2 u = vec2(rand01(), rand01());
+		vec3 brdf_weight = vec3(0.);
+		if (!evalIndirectCombinedBRDF(u, shading_normal, geometry_normal, -direction, material, brdf_type, bounce_direction, brdf_weight))
+			return false;
+		throughput *= brdf_weight;
+	}
+
+	const float throughput_threshold = 1e-3;
+	if (dot(throughput, throughput) < throughput_threshold)
+		return false;
+
+	return true;
+#endif
+}
 
 #endif //ifndef BRDF_GLSL_INCLUDED