Materials and textures in Unity - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Unity C# code when applying a texture?

Consider the following Unity C# script snippet that assigns a texture to a material. What will be the color of the material's main texture pixel at (0,0) after this code runs?

Unity

Texture2D tex = new Texture2D(2, 2);
tex.SetPixel(0, 0, Color.red);
tex.SetPixel(1, 0, Color.green);
tex.SetPixel(0, 1, Color.blue);
tex.SetPixel(1, 1, Color.white);
tex.Apply();

Material mat = new Material(Shader.Find("Standard"));
mat.mainTexture = tex;

Color pixelColor = ((Texture2D)mat.mainTexture).GetPixel(0, 0);
Debug.Log(pixelColor);

A RGBA(1.000, 0.000, 0.000, 1.000)

B RGBA(0.000, 0.000, 1.000, 1.000)

C RGBA(0.000, 1.000, 0.000, 1.000)

D RGBA(1.000, 1.000, 1.000, 1.000)

💡 Hint

Remember that SetPixel sets the color at the specified coordinates before Apply() updates the texture.

The pixel at (0,0) was set to Color.red, so when we read it back, it returns red.

🧠 Conceptual

intermediate

Which Unity shader property controls the smoothness of a material?

In Unity's Standard Shader, which property name is used to control how smooth or shiny a material appears?

A "_Emission"

B "_Metallic"

C "_BumpMap"

D "_Glossiness"

💡 Hint

Think about the term that relates to surface reflection sharpness.

The "_Glossiness" property controls the smoothness or shininess of the material's surface.

🔧 Debug

advanced

Why does this texture not appear on the material in Unity?

Look at this code snippet. The texture is created and assigned to the material, but the object remains untextured in the scene. What is the most likely cause?

Unity

Texture2D tex = new Texture2D(128, 128);
// Forgot to call tex.Apply()
for (int y = 0; y < 128; y++) {
    for (int x = 0; x < 128; x++) {
        tex.SetPixel(x, y, Color.yellow);
    }
}
Material mat = new Material(Shader.Find("Standard"));
mat.mainTexture = tex;

A The material was not assigned to any renderer component.

B The texture size is too large and causes a memory overflow.

C The texture was never applied with tex.Apply(), so changes are not updated.

D The shader "Standard" does not support textures.

💡 Hint

Remember that Texture2D changes require a specific method call to update.

Without calling tex.Apply(), the texture changes are not sent to the GPU, so the material shows no texture.

📝 Syntax

advanced

Which option correctly creates a tiled texture offset in Unity C#?

You want to tile a texture twice in both X and Y directions and offset it by 0.5 on X axis. Which code snippet correctly sets this on a material?

A

mat.mainTextureScale = new Vector2(2, 2);
mat.mainTextureOffset = new Vector2(0.5f, 0);

B

mat.SetTextureScale("_MainTex", new Vector2(2, 2));
mat.SetTextureOffset("_MainTex", new Vector2(0.5f, 0));

C

mat.mainTextureScale = new Vector2(0.5f, 0);
mat.mainTextureOffset = new Vector2(2, 2);

D

mat.SetTextureScale("_MainTex", new Vector2(0.5f, 0));
mat.SetTextureOffset("_MainTex", new Vector2(2, 2));

💡 Hint

Remember that mainTextureScale and mainTextureOffset are properties, but SetTextureScale and SetTextureOffset require the texture property name.

Using SetTextureScale and SetTextureOffset with "_MainTex" is the correct way to set tiling and offset for the main texture.

🚀 Application

expert

How many unique colors will this procedural texture contain?

This Unity C# code creates a 4x4 texture where each pixel color depends on its coordinates. How many unique colors does the resulting texture have?

Unity

Texture2D tex = new Texture2D(4, 4);
for (int y = 0; y < 4; y++) {
    for (int x = 0; x < 4; x++) {
        Color c = (x == y) ? Color.black : Color.white;
        tex.SetPixel(x, y, c);
    }
}
tex.Apply();

A 2

B 4

C 8

D 16

💡 Hint

Think about how many pixels are black and how many are white.

Pixels on the diagonal (where x == y) are black, all others are white, so only two unique colors exist.