Bird
Raised Fist0
Unityframework~5 mins

Unlit vs lit shaders in Unity

Choose your learning style10 modes available
LearnWhyDeepVisualTryChallengeProjectRecallPerf
Introduction

Shaders control how objects look in a game. Unlit shaders show colors without light effects. Lit shaders change appearance based on light.

When you want a flat color or texture that doesn't change with light, like UI elements or cartoon styles.
When you want realistic surfaces that react to light, like shiny metals or rough walls.
When you need simple graphics that don't need lighting to save performance.
When you want shadows and highlights on objects to make them look 3D.
When creating special effects that ignore scene lighting, like glowing signs.
Syntax
Unity
Shader "Custom/UnlitShader" {
  SubShader {
    Pass {
      // Unlit shader code here
    }
  }
}

Shader "Custom/LitShader" {
  Properties {
    _Color ("Color", Color) = (1,1,1,1)
  }
  SubShader {
    Tags { "RenderType"="Opaque" }
    LOD 200
    Pass {
      // Lit shader code here
    }
  }
}

Unlit shaders do not use lighting calculations.

Lit shaders include lighting and shading calculations for realism.

Examples
This unlit shader colors everything red without any light effect.
Unity
Shader "Custom/UnlitColor" {
  SubShader {
    Pass {
      CGPROGRAM
      #pragma vertex vert
      #pragma fragment frag

      struct appdata {
        float4 vertex : POSITION;
      };

      struct v2f {
        float4 pos : SV_POSITION;
      };

      v2f vert(appdata v) {
        v2f o;
        o.pos = UnityObjectToClipPos(v.vertex);
        return o;
      }

      fixed4 frag(v2f i) : SV_Target {
        return fixed4(1, 0, 0, 1); // red color
      }
      ENDCG
    }
  }
}
This lit shader colors the object green and reacts to light for shading.
Unity
Shader "Custom/LitSimple" {
  Properties {
    _Color ("Color", Color) = (0,1,0,1)
  }
  SubShader {
    Tags { "RenderType"="Opaque" }
    LOD 200
    CGPROGRAM
    #pragma surface surf Standard

    fixed4 _Color;

    struct Input {
      float3 worldNormal;
      float3 worldPos;
    };

    void surf(Input IN, inout SurfaceOutputStandard o) {
      o.Albedo = _Color.rgb;
      o.Metallic = 0.0;
      o.Smoothness = 0.5;
    }
    ENDCG
  }
}
Sample Program

This program defines two shaders: one unlit that shows red color always, and one lit that shows green color reacting to lights in the scene.

Unity
// This example shows a simple unlit shader and a lit shader in Unity

// Unlit shader colors object red without lighting
Shader "Custom/UnlitRed" {
  SubShader {
    Pass {
      CGPROGRAM
      #pragma vertex vert
      #pragma fragment frag

      struct appdata {
        float4 vertex : POSITION;
      };

      struct v2f {
        float4 pos : SV_POSITION;
      };

      v2f vert(appdata v) {
        v2f o;
        o.pos = UnityObjectToClipPos(v.vertex);
        return o;
      }

      fixed4 frag(v2f i) : SV_Target {
        return fixed4(1, 0, 0, 1); // red color
      }
      ENDCG
    }
  }
}

// Lit shader colors object green and reacts to light
Shader "Custom/LitGreen" {
  Properties {
    _Color ("Color", Color) = (0,1,0,1)
  }
  SubShader {
    Tags { "RenderType"="Opaque" }
    LOD 200
    CGPROGRAM
    #pragma surface surf Standard

    fixed4 _Color;

    struct Input {
      float3 worldNormal;
      float3 worldPos;
    };

    void surf(Input IN, inout SurfaceOutputStandard o) {
      o.Albedo = _Color.rgb;
      o.Metallic = 0.0;
      o.Smoothness = 0.5;
    }
    ENDCG
  }
}
OutputSuccess
Important Notes

Unlit shaders are faster because they skip lighting calculations.

Lit shaders give more realistic visuals but use more processing power.

Use unlit for UI or stylized looks, lit for realistic 3D objects.

Summary

Unlit shaders show colors without light effects.

Lit shaders calculate light and shadows for realism.

Choose shader type based on your visual and performance needs.

Practice

(1/5)
1. What is the main difference between Unlit and Lit shaders in Unity?
easy
A. Unlit shaders do not react to lighting, Lit shaders do
B. Unlit shaders are slower than Lit shaders
C. Lit shaders ignore shadows, Unlit shaders show shadows
D. Lit shaders only work on 2D objects

Solution

  1. Step 1: Understand Unlit shader behavior

    Unlit shaders display colors without any lighting or shadow effects.

  2. Step 2: Understand Lit shader behavior

    Lit shaders calculate lighting and shadows to create realistic visuals.

  3. Final Answer:

    Unlit shaders do not react to lighting, Lit shaders do -> Option A

  4. Quick Check:

    Lighting reaction = Unlit no, Lit yes [OK]
Hint: Unlit means no light effects, Lit means light and shadows [OK]
Common Mistakes:
  • Thinking Unlit shaders are slower
  • Believing Lit shaders ignore shadows
  • Assuming Lit shaders only work on 2D
2. Which of the following is the correct way to assign an Unlit shader to a material in Unity's Shader dropdown?
easy
A. Shaders > Unlit > Color
B. Shaders > Legacy Shaders > Transparent
C. Shaders > Standard
D. Shaders > Lit > PBR

Solution

  1. Step 1: Locate Unlit shaders in Unity

    Unlit shaders are found under the menu path: Shaders > Unlit > Color.

  2. Step 2: Confirm correct shader assignment

    Assigning 'Unlit > Color' applies an unlit shader that ignores lighting.

  3. Final Answer:

    Shaders > Unlit > Color -> Option A

  4. Quick Check:

    Unlit shader path = Shaders > Unlit > Color [OK]
Hint: Unlit shaders are under Shaders > Unlit in dropdown [OK]
Common Mistakes:
  • Choosing Standard shader which is lit
  • Selecting Legacy shaders unrelated to unlit
  • Picking Lit shaders for unlit materials
3. Given this Unity shader code snippet, what will be the visual result on a 3D object?
Shader "Custom/Example" {
  SubShader {
    Tags { "RenderType"="Opaque" }
    Pass {
      CGPROGRAM
      #pragma vertex vert
      #pragma fragment frag
      struct appdata { float4 vertex : POSITION; };
      struct v2f { float4 pos : SV_POSITION; };
      v2f vert(appdata v) { v2f o; o.pos = UnityObjectToClipPos(v.vertex); return o; }
      fixed4 frag(v2f i) : SV_Target { return fixed4(1,0,0,1); }
      ENDCG
    }
  }
}
medium
A. The object will flicker between colors
B. The object will be shaded with light and shadows
C. The object will be invisible
D. The object will appear bright red without lighting effects

Solution

  1. Step 1: Analyze the fragment shader output

    The fragment shader returns fixed4(1,0,0,1), which is solid red color.

  2. Step 2: Check for lighting calculations

    No lighting or normal calculations exist, so color is unlit and constant.

  3. Final Answer:

    The object will appear bright red without lighting effects -> Option D

  4. Quick Check:

    Fragment color fixed red, no lighting = unlit red [OK]
Hint: No lighting code means solid color output [OK]
Common Mistakes:
  • Assuming lighting affects color here
  • Thinking object is invisible without lighting
  • Expecting color changes or flickering
4. You wrote a Lit shader but the object appears completely black in your scene. What is the most likely cause?
medium
A. The object has no mesh assigned
B. The shader is missing normal vector calculations
C. The shader is set to Unlit accidentally
D. The camera is disabled

Solution

  1. Step 1: Understand Lit shader requirements

    Lit shaders need normal vectors to calculate lighting properly.

  2. Step 2: Identify missing normal vector effect

    If normals are missing or incorrect, lighting calculations fail, causing black appearance.

  3. Final Answer:

    The shader is missing normal vector calculations -> Option B

  4. Quick Check:

    Missing normals = no lighting = black object [OK]
Hint: Lit shaders need normals for lighting; missing normals cause black [OK]
Common Mistakes:
  • Blaming mesh or camera instead of shader code
  • Confusing Unlit shader with Lit shader issues
  • Ignoring normal vector importance
5. You want to optimize a mobile game by reducing lighting calculations but still want some color variation. Which shader approach is best?
hard
A. Use Unlit shaders with no color variation
B. Use fully Lit shaders with multiple lights
C. Use Unlit shaders with vertex colors for variation
D. Use Lit shaders but disable shadows

Solution

  1. Step 1: Consider performance needs

    Reducing lighting calculations improves performance on mobile devices.

  2. Step 2: Choose shader with color variation but no lighting

    Unlit shaders with vertex colors provide color changes without expensive lighting.

  3. Final Answer:

    Use Unlit shaders with vertex colors for variation -> Option C

  4. Quick Check:

    Unlit + vertex colors = color variation without lighting cost [OK]
Hint: Unlit + vertex colors = color without lighting cost [OK]
Common Mistakes:
  • Using full Lit shaders which are costly
  • Choosing Unlit with no color variation loses visual interest
  • Disabling shadows alone doesn't reduce lighting cost fully
Recommended

Ready to prove it?

Pass the test and this pattern moves unknown strong while earning +1 Grip toward your certificate.

10 questions~5 mineasy hard