Unity - SpriteRenderer. Trying to make sprite from code using Texture2d.whitetexture

Question

I have been trying to write a method that fills a rectangle with a color. I've tried it as a new 2D and 3D project just in case, but this gives the same results.

Basically, i want the script to make a new GameObject, give it a SpriteRenderer component and then fill the given rectangle with the given color.

I have tried to work from the Unity docs and other sources of info, but no matter how much I look around, this now looks correct to me but doesnt work.

The result (as pictured) shows the new object with the sprite renderer and even shows the right size (there are blue 'corner' icons in the scene view I can see but no sprite or rectangle of any kind.

using UnityEngine;


public class GameBoard : MonoBehaviour
{
    const ushort cellCount_x = 10;
    const ushort cellCount_y = 24; // only 20 will be visible to player
    const ushort cellsize = 50;

    GameObject testBlock;
    SpriteRenderer testBlockRen;

    private void Start()
    {
        testBlock = new GameObject();
        testBlockRen = testBlock.AddComponent<SpriteRenderer>();
        testBlockRen.sprite = CreateRectSprite(new Rect(0, 0, cellsize, cellsize), Color.red);
    }

    Sprite CreateRectSprite(Rect rect, Color color)
    {
        Texture2D tex = Texture2D.whiteTexture;
        tex.SetPixel(0, 0, color);
        tex.Resize((int)rect.width, (int)rect.height);
        Sprite sprite = Sprite.Create(tex, rect, Vector2.zero);
        return sprite;
    }
}

By the way: I have made sure the camera 'z' is less than 0 (it's -10). And the camera is centred where the sprite is supposed to appear.

Note: I can get a sprite to render fine if I create a texture in gimp and then use Resources.Load() . But I am trying to create the sprite using no source texture whatsoever (other than Texture2d.whitetexture)

Answer 1

You can make sprite with code by using Sprite.Create

https://docs.unity3d.com/ScriptReference/Sprite.Create.html

Sprite.Create creates a new Sprite which can be used in game applications. A texture needs to be loaded and assigned to Create in order to control how the new Sprite will look. In the script example below a new Sprite is displayed when the button is pressed. The new sprite is created in Start.

red rectangle

using UnityEngine;

public class SimpleRectangle: MonoBehaviour
{
    private Sprite mySprite;
    private SpriteRenderer sr;
    public Color color = Color.red;

    void Awake()
    {
        sr = GetComponent<SpriteRenderer>();
        sr.color = color;

        transform.position = new Vector3(1.5f, 1.5f, 0.0f);
    }

    void Start()
    {
        Texture2D tex = new Texture2D(500,250);
        mySprite = Sprite.Create(tex, new Rect(0.0f, 0.0f, tex.width, tex.height), new Vector2(0.5f, 0.5f), 100.0f);
        sr.sprite = mySprite;
    }
}

another example , simple checker texture with code: try to change height and width in editor

using UnityEngine;

[ExecuteInEditMode]
public class SimpleChecker: MonoBehaviour
{
    [Range(1,10)]
    public int height = 10,width = 10;

    private void Update() {
    Texture2D texture = new Texture2D(128, 128);
    GetComponent<SpriteRenderer>().sprite = Sprite.Create(CreateTexture(texture), new Rect(0.0f, 0.0f, texture.width, texture.height), new Vector2(0.5f, 0.5f), 100.0f);

    }
    public Texture2D CreateTexture(Texture2D texture){

        for (int y = 0; y < texture.height; y++)
        {
            for (int x = 0; x < texture.width; x++)
            {
                Color color = (x/height % 2 + y/width % 2 ) == 1 ? Color.white : Color.black;
                texture.SetPixel(x, y, color);
            }
        }
        texture.Apply();
    return texture;
    }
}

Update

your code didn't work because you forgot to use tex.Apply();

using UnityEngine;


public class GameBoard : MonoBehaviour
{
  const ushort cellCount_x = 10;
    const ushort cellCount_y = 24; // only 20 will be visible to player
    const ushort cellsize = 50;

    GameObject testBlock;
    SpriteRenderer testBlockRen;

    private void Start()
    {
        testBlock = new GameObject();
        testBlockRen = testBlock.AddComponent<SpriteRenderer>();
        testBlockRen.sprite = CreateRectSprite(new Rect(0, 0, cellsize, cellsize),Color.red);
    }

    Sprite CreateRectSprite(Rect rect,Color color)
    {
        Texture2D tex = Texture2D.whiteTexture;
        tex.Resize((int)rect.width, (int)rect.height);
        for (int x = 0; x < (int)rect.width; x++){
             for (int y = 0; y < rect.height; y++){
                 tex.SetPixel(x, y, color); 
             }
         }
        tex.Apply();
        Sprite sprite = Sprite.Create(tex, rect, Vector2.zero);
        return sprite;
    }
}