Creating A Gradient Texture And Applying It At Runtime

Hi, I wanted to create a gradient from a transparent white to a opaque black for my quad to overlay onto a different texture. The problem is that it doesn't seem like the texture is being applied correctly to the quad.

GradientTexture Script:

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Code (csharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class GradientTexture : MonoBehaviour {
6.     [Header("Type of Gradient")]
7.     [Tooltip("0 = downward to black")]
8.     public int type = 0;
9.  
10.     void Start () {
11.         float width = transform.lossyScale.x;
12.         float height = transform.lossyScale.y;
13.  
14.         Gradient gradient = new Gradient();
15.         Texture2D texture = new Texture2D(Mathf.CeilToInt(width), Mathf.CeilToInt(height));
16.         texture.alphaIsTransparency = true;
17.  
18.         switch(type) {
19.         case(0): {
20.                 gradient.SetKeys(DARKNESS_COLOR_KEY, DARKNESS_ALPHA_KEY);
21.  
22.                 float yStep = 1F / height;
23.  
24.                 print("Height: " + height);
25.                 print("yStep: " + yStep);
26.  
27.                 for(int y = 0; y < Mathf.CeilToInt(height); y++) {
28.                     Color color = gradient.Evaluate(y * yStep);
29.                     print("Y: " + y + " | R: " + color.r + " G: " + color.g + " B: " + color.b + " A: " + color.a);
30.  
31.                     for(int x = 0; x < Mathf.CeilToInt(width); x++) {
32.                         texture.SetPixel(Mathf.CeilToInt(x), Mathf.CeilToInt(y), color);
33.                     }
34.                 }
35.                    
36.                 break;
37.             }
38.         }
39.  
40.         GetComponent<Renderer>().material.mainTexture = texture;
41.     }
42.  
43.     public static GradientColorKey[] DARKNESS_COLOR_KEY = {new GradientColorKey(Color.black, 0), new GradientColorKey(Color.black, 1)};
44.     public static GradientAlphaKey[] DARKNESS_ALPHA_KEY = {new GradientAlphaKey(0, 0), new GradientAlphaKey(1, 1)};
45.  
46. }
47.  

I believe I'm creating the gradient correctly, as the print shows that as the y increases the alpha increments to 1. Before running, the quad takes on the default-checker texture from Unity. After the game finishes loading, the quad is completely invisible.

Here is the quad object ("Darkness") and the material it uses:

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It also creates a strange rendering artifact along its diagonals during run:

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Finally, here is the desired effect:

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Sorry if I misunderstand most responses; I am entirely new to Unity, graphics, and C#, and only have experience in Java.

 

I found the problem, I forgot the apply the texture (texture.Apply()).

 

Hi,
What is the advantage of creating the texture procedurally vs using a ready made texture in your game context ?

 

A lot