Blend damage revealed with noise texture mask

I created this shader to reveal damage on an object, using a noise texture as mask to create blots of damage that will eventually grow and cover the whole surface. It requires:

• Base Texture: showing the “untouched” state of the object.
• Damage Texture: showing the damaged state of the object.
• Noise Texture: a NoiseTexture2D that you can generate in Godot itself, used as mask.

You can control the damage amount using the instance parameters:

• Damage Amount: Ranges from 0 to 100, where 100 will show the Damage Texture at 100% visibilty.
• Treshold: From which percentage no damage is yet visible. Defaults at 25%.

Shader code

shader_type spatial;

uniform sampler2D BaseTexture;
uniform sampler2D DamageTexture : hint_default_black;
uniform sampler2D NoiseTexture;
instance uniform float DamageAmount : hint_range(0, 100) = 0;
instance uniform float Treshold = 25.0;

void fragment() {
	vec4 damage_tex = texture(DamageTexture, UV);
	vec4 base_tex = texture(BaseTexture, UV);
	vec4 noise_tex = texture(NoiseTexture, UV);

	float scalar = noise_tex.x * DamageAmount;
	float smooth_step = smoothstep(scalar, DamageAmount, Treshold);

	vec3 output = mix(vec3(damage_tex.xyz), vec3(base_tex.xyz), vec3(smooth_step));

	ALBEDO = output;
}

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