3D Health Bar

World’s simplest health bar.

• Works best on QuadMesh or Sprite3D since these allow billboarding (optional).
• Allows transparancy through Alpha Channel.
• No textures: Just colors.
• Uses an instance variable for health, so you don’t have to make the material unique: It will display amount of health automatically for each instance.

Shader parameters:

• Use Billboard: If true, the Mesh will always face the camera from any angle.
• Color: Color indicating the amount of health.
• Background Color: The background color of the full healthbar, exposed when health is taken away.

Instance shader parameters:

• Health: Controls the lenght of the color, between 0 and 1. Since this is an instance parameter, the material does not have to be made unique.

Shader code

shader_type spatial;
render_mode unshaded;

uniform bool use_billboard;
uniform vec4 color : source_color = vec4(1.0, 1.0, 1.0, 1.0);
uniform vec4 background_color : source_color = vec4(1.0, 1.0, 1.0, 1.0);
instance uniform float health : hint_range(0.0, 1.0) = 0.5;

void vertex() {
	if (use_billboard){
        MODELVIEW_MATRIX = VIEW_MATRIX * mat4(INV_VIEW_MATRIX[0], INV_VIEW_MATRIX[1], INV_VIEW_MATRIX[2], MODEL_MATRIX[3]);
	}
}

void fragment() {
	ALBEDO = UV.x < health ? color.rgb : background_color.rgb;
	ALPHA = UV.x < health ? color.a : background_color.a;
}

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