Unity: Textures & Materials — How to Make a Game (Beginners)

This quick guide covers what textures and materials are, how they work with shaders, and how to wire them up in Unity (URP/Standard). Keep it open while you build.

1) Core Ideas

• Texture: an image (PNG/JPG/TGA/EXR) that stores visual data like color, bumps, metalness, etc.
• Material: a recipe that tells Unity how to draw a surface; it plugs textures into a shader.
• Shader: the math the GPU uses to render; PBR shaders (Standard/URP/HDRP) expect specific texture maps.

2) Essential PBR Texture Maps

3) Importing Textures (Settings That Matter)

1. Drag textures into the Project window.
2. Select a texture and set:
   • Texture Type: Color maps → Default (sRGB ON); Normal → Normal map; Data maps (metallic/roughness/ao) → Default (sRGB OFF).
   • Compression: Normal quality is fine to start.
   • Generate Mip Maps: ON for 3D surfaces.
   • Aniso Level: Increase (2–8) for floors/walls viewed at glancing angles.

4) Make a Material & Wire Textures (URP Lit Example)

1. Create → Material (e.g., Mat_BrickWall).
2. Inspector → Shader: Universal Render Pipeline/Lit.
3. Assign maps:
   • Base Map: Albedo/BaseColor texture.
   • Normal Map: Normal texture (apply fix prompt).
   • Metallic/Smoothness: If you have Metallic (Smoothness in Alpha), use it; if you only have Roughness, invert to Smoothness first.
   • AO: Assign if the shader slot is available.
   • Emission: Enable Emission and assign color/map; for visible glow add Bloom in Post Processing.
4. Tiling & Offset: Adjust to fit large surfaces (e.g., 2×2 or 3×3).
5. Apply: Drag the material onto a mesh in the Scene view or set it in the Mesh Renderer.

5) 5‑Minute Mini Tutorial

1. Create a Plane (floor) and a Cube: GameObject → 3D Object.
2. Import floor textures (albedo, normal, roughness, AO).
3. Create Mat_Floor (URP Lit) and assign maps as above.
4. Set Tiling to repeat nicely (e.g., 3×3).
5. Ensure a Directional Light exists and shadows are enabled.
6. (URP) Add a Global Volume with Bloom if you use Emission.

6) Materials, Shaders, and Pipelines

• Standard (Built‑in): PBR with Metallic workflow.
• URP Lit: Efficient PBR for most platforms (great default).
• HDRP Lit: High‑end visuals (PC/console).
• Shader Graph: Visual tool for custom shaders (toon, dissolve, etc.).

7) UVs, Tiling, and Seams

• UVs tell Unity how to place textures on a mesh.
• If tiling is obvious, use seamless textures, vary tiling/offset, or blend detail maps.
• Stretched textures often mean poor UV unwrap (fix in Blender/Maya).

8) Transparency & Cutouts

• Surface Type: Opaque, Transparent, or Alpha Clipping.
• Transparent = glass/water (alpha blending). Alpha Clipping = leaves (hard edge, cheaper).

9) Performance Tips

• Use reasonable texture sizes (512–1024 for props).
• Atlas small textures to reduce draw calls.
• Share materials across objects (fewer materials = better batching).
• Enable GPU Instancing on widely reused materials.
• Use platform compression (ASTC/ETC2 mobile, DXT/BC desktop).

10) Common Pitfalls & Fixes

• Normal looks flat/weird: Mark as Normal map; sRGB OFF.
• Too shiny/dull: Smoothness wrong. If using Roughness, invert to Smoothness.
• Metal looks gray: Check albedo (metals take color from albedo) and set Metallic correctly.
• AO not visible: Correct slot and proper lighting; AO is a multiplier.
• Emission not glowing: Enable Bloom in post processing and raise intensity.

11) Tiny Script: Tweak a Material at Runtime (URP)

using UnityEngine;

public class MaterialTweaker : MonoBehaviour
{
    public Renderer targetRenderer; // assign in Inspector
    public Texture2D newAlbedo;
    public Color tint = Color.white;

    void Start()
    {
        var block = new MaterialPropertyBlock();
        targetRenderer.GetPropertyBlock(block);

        block.SetColor("_BaseColor", tint);      // URP Lit color
        block.SetTexture("_BaseMap", newAlbedo); // URP Lit albedo slot
        block.SetFloat("_Metallic", 0.7f);
        block.SetFloat("_Smoothness", 0.6f);

        targetRenderer.SetPropertyBlock(block);
    }
}

For Built‑in/Standard shader, use property names like _Color, _MainTex, _Metallic, _Glossiness.

12) Student Checklist

• Correct Texture Type & sRGB settings
• Normal map recognized as Normal map
• Metallic/Smoothness correct (or Roughness inverted)
• AO/Emission assigned when available
• Scene lighting ok; shadows on
• Tiling/Offset tuned on large surfaces
• (URP) Global Volume with Bloom for emission glow
• Texture sizes & compression set for target platform