 	_k1.x = dot(_k1, o_tangent);
 	_k1.y = dot(_k1, o_bitangent);
 	_k1.z = dot(_k1, o_normal);
-	
+	_k1 = normalize(_k1);
 	
 	
 	vec3 V = _k1 - _k2;

			float abs_P_Sq = P.x*P.x + P.y*P.y;
			float diffractionCoeff = getFactor(k, F, G, w);
			vec3 waveColor = avgWeighted_XYZ_weight(lambda_iter);
//			brdf += vec4(diffractionCoeff * abs_P_Sq * waveColor, 1.0);
//			maxBRDF += vec4(waveColor, 1.0);	
		}
	}else{
		// iterate twice: once for N_u and once for N_v lower,upper

	vec3 _k1 = normalize(o_light); // light direction, same for every point		
	
	
	float in_angle_deg = 45.0;
	
	float alpha_deg = (90.0-in_angle_deg)/2.0;
	float alpha_rad = (PI*alpha_deg)/180.0;	
