How to increase ligh energy in a shader

:information_source: Attention Topic was automatically imported from the old Question2Answer platform.
:bust_in_silhouette: Asked By Artium Nihamkin
:warning: Old Version Published before Godot 3 was released.

Hi, I have a 2D sprite with normal map and I use the following fragment shader to give it a 3D effect:

uniform texture normal;
//normal maps expect Y-up, but 2D is Y-down, so must mirror this.
NORMAL = tex(normal,UV).rgb * vec3(2.0,-2.0,1.0) - vec3(1.0,-1.0,0.0);

The problem is that the effect is almost invisible if the energy of the light is low. But if I set it to high, the lightning of the background does not look good.

How can I increase the energy in the shader itself?

Energy 1

Energy 10