Shader de aplicar tonalidade ( Sepia, black&white) Godot 4

Shader de aplicar tonalidade ( Sepia, black&white) Godot 4

shader_type canvas_item;

uniform vec4 base : source_color;
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;

void fragment() {
    vec3 c = textureLod(SCREEN_TEXTURE, SCREEN_UV, 0.0).rgb;
    float v = dot(c, vec3(0.33333, 0.33333, 0.33333));
    v = sqrt(v);
    COLOR.rgb = base.rgb * v;
}