Using advise from Matias, left the 0-1 range for lights, divisiom by PI, and multiplied lights by PI internally.

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -2534,9 +2534,10 @@ void RasterizerSceneGLES3::_setup_directional_light(int p_index, const Transform
 	float sign = li->light_ptr->negative ? -1 : 1;
 
 	Color linear_col = li->light_ptr->color.to_linear();
-	ubo_data.light_color_energy[0] = linear_col.r * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
-	ubo_data.light_color_energy[1] = linear_col.g * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
-	ubo_data.light_color_energy[2] = linear_col.b * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
+	//compensate normalized diffuse range by multiplying by PI
+	ubo_data.light_color_energy[0] = linear_col.r * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
+	ubo_data.light_color_energy[1] = linear_col.g * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
+	ubo_data.light_color_energy[2] = linear_col.b * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
 	ubo_data.light_color_energy[3] = 0;
 
 	//omni, keep at 0
@@ -2674,9 +2675,9 @@ void RasterizerSceneGLES3::_setup_lights(RID *p_light_cull_result, int p_light_c
 				float sign = li->light_ptr->negative ? -1 : 1;
 
 				Color linear_col = li->light_ptr->color.to_linear();
-				ubo_data.light_color_energy[0] = linear_col.r * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
-				ubo_data.light_color_energy[1] = linear_col.g * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
-				ubo_data.light_color_energy[2] = linear_col.b * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
+				ubo_data.light_color_energy[0] = linear_col.r * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
+				ubo_data.light_color_energy[1] = linear_col.g * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
+				ubo_data.light_color_energy[2] = linear_col.b * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
 				ubo_data.light_color_energy[3] = 0;
 
 				Vector3 pos = p_camera_inverse_transform.xform(li->transform.origin);
@@ -2760,9 +2761,9 @@ void RasterizerSceneGLES3::_setup_lights(RID *p_light_cull_result, int p_light_c
 				float sign = li->light_ptr->negative ? -1 : 1;
 
 				Color linear_col = li->light_ptr->color.to_linear();
-				ubo_data.light_color_energy[0] = linear_col.r * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
-				ubo_data.light_color_energy[1] = linear_col.g * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
-				ubo_data.light_color_energy[2] = linear_col.b * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY];
+				ubo_data.light_color_energy[0] = linear_col.r * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
+				ubo_data.light_color_energy[1] = linear_col.g * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
+				ubo_data.light_color_energy[2] = linear_col.b * sign * li->light_ptr->param[VS::LIGHT_PARAM_ENERGY] * M_PI;
 				ubo_data.light_color_energy[3] = 0;
 
 				Vector3 pos = p_camera_inverse_transform.xform(li->transform.origin);

drivers/gles3/shaders/scene.glsl

@@ -915,7 +915,7 @@ LIGHT_SHADER_CODE
 
 #if defined(DIFFUSE_LAMBERT_WRAP)
 	//energy conserving lambert wrap shader
-	light_amount = max(0.0,(dot(N,L) + roughness) / ((1.0 + roughness) * (1.0 + roughness)));
+	light_amount = max(0.0,(dot(N,L) + roughness) / ((1.0 + roughness) * (1.0 + roughness) * M_PI));
 
 #elif defined(DIFFUSE_OREN_NAYAR)
 
@@ -932,8 +932,7 @@ LIGHT_SHADER_CODE
 		vec3 A = 1.0 + sigma2 * (- 0.5 / (sigma2 + 0.33) + 0.17*diffuse_color / (sigma2 + 0.13) );
 		float B = 0.45 * sigma2 / (sigma2 + 0.09);
 
-//		light_amount = dotNL * (A + vec3(B) * s / t) / M_PI;
-		light_amount = dotNL * (A + vec3(B) * s / t);
+		light_amount = dotNL * (A + vec3(B) * s / t) / M_PI;
 	}
 
 #elif defined(DIFFUSE_TOON)
@@ -953,8 +952,7 @@ LIGHT_SHADER_CODE
 		float FD90 = 0.5 + 2.0 * LoH * LoH * roughness;
 		float FdV = 1.0 + (FD90 - 1.0) * SchlickFresnel(NoV);
 		float FdL = 1.0 + (FD90 - 1.0) * SchlickFresnel(NoL);
-		//light_amount = ( (1.0 / M_PI) * FdV * FdL ) * NoL;
-		light_amount = ( FdV * FdL ) * NoL;
+		light_amount = ( (1.0 / M_PI) * FdV * FdL ) * NoL;
 /*
 		float energyBias = mix(roughness, 0.0, 0.5);
 		float energyFactor = mix(roughness, 1.0, 1.0 / 1.51);
@@ -967,8 +965,7 @@ LIGHT_SHADER_CODE
 	}
 #else
 	//lambert
-//	light_amount = dotNL / M_PI;
-	light_amount = dotNL;
+	light_amount = dotNL / M_PI;
 #endif
 
 #if defined(TRANSMISSION_USED)