Hello, I'm wondering if anyone can explain this Directional Light behavior.
Godot Version: 3.2.1
I'm using the shader below on a sphere. The shader uses the vertex and fragment shader simply to override the built-in Godot shaders, and disables ambient lighting. Also, there is a blank WorldEnvironment node in the SceneTree, so in theory there's no light affecting the sphere from the environment.
The light shader assigns a constant color to DIFFUSE_LIGHT making the sphere dark red. Notice I'm not using +=, so the color should be constant no matter how many lights are in the scene.
However, when I add multiple directional lights, each seems to increase the brightness of the sphere. This effect only occurs with directional lights, not omni or spot lights.
I would like to know why and how to stop it.
If I can figure this out, the next version of my Cel Shader might be able to use multiple directional lights.
shader_type spatial;
render_mode ambient_light_disabled;
void vertex() {VERTEX = VERTEX;}
void fragment() {ALBEDO = vec3(0.0, 0.0, 0.0);}
void light()
{
DIFFUSE_LIGHT = vec3(0.1, 0.0, 0.0);
}
Sphere with one directional light...

Sphere with five directional lights...
