Hide part of the GUITexture in Unity

Question

I have a Health Bar in my Unity game and it's implemented as a GUITexture with gradient image from red to green.

Now I can reduce it's width from max width to 0, but is still scaled gradient.

public void UpdateHealthBar(int hitPoints) {
    healthBar.pixelInset = new Rect(
        healthBar.pixelInset.x, healthBar.pixelInset.y,
        3* hitPoints, healthBar.pixelInset.height);
}

But I want to hide (make transparent) the right part of this health bar in game progress.

How can I do this? Thanks!

Answer 1

Or you can use GUI.DrawTextureWithTexCoords()

public Texture2D texture;
public float hp = 100f;
public const float hpMax = 100f;

void OnGUI()
{
    GUI.DrawTextureWithTexCoords (new Rect (0, 0, hp, 20), texture, new Rect (0f, 0f, hp/hpMax, 1f));
}

Answer 2

As Bart suggested, you can use GUI.BeginGroup

Here is an example

public Texture2D texture;
public Rect textureCrop = new Rect( 0.1f, 0.1f, 0.5f, 0.25f );
public Vector2 position = new Vector2( 10, 10 );

void OnGUI()
{
    GUI.BeginGroup( new Rect( position.x, position.y, texture.width * textureCrop.width, texture.height * textureCrop.height ) );
    GUI.DrawTexture( new Rect( -texture.width * textureCrop.x, -texture.height * textureCrop.y, texture.width, texture.height ), texture );
    GUI.EndGroup();
}