fixed4 c = lerp(_ColorA, _ColorB, tex.y / _Middle) * step(tex.y, _Middle);
c += lerp(_ColorB, _ColorC, (tex.y - _Middle) / (1 - _Middle)) * step(_Middle, tex.y);

private Texture2D _tex; //Texture that will go into the shader
private Renderer _rend; //Renderer of the object

private void Awake () {
    _rend = this.GetComponent<Renderer> ();

    //create new texture, width == amount of colors
    _tex = new Texture2D (4, 1);

    //Set each pixel to specified color (StarGradient is function below)
    _tex.SetPixels32 (StarGradient (
        new Color32 (255, 186, 0, 1),
        new Color32 (224, 100, 45, 1),
        new Color32 (118, 73, 41, 1),
        new Color32 (60, 73, 55, 1))
    );
    _tex.filterMode = FilterMode.Trilinear;
    _tex.wrapMode = TextureWrapMode.Clamp;
    _tex.Apply ();

    //Pass _tex to the material
    _rend.material.SetTexture ("_RampTex", _tex);
}

//Returns a Color32 array of specified colors
private Color32[] StarGradient(Color32 a, Color32 b, Color32 c, Color32 d) {
    Color32[] _colors = new Color32[4];
    _colors [0] = a;
    _colors [1] = b;
    _colors [2] = c;
    _colors [3] = d;
    return _colors;
}

private void Awake () {
    _rend = this.GetComponent<Renderer> ();

    //create new texture, width == amount of colors
    _tex = new Texture2D (4, 1);

    //Set each pixel to specified color (StarGradient is function below)
    _tex.SetPixels32 (StarGradient (
        new Color32 (255, 186, 0, 1),
        new Color32 (224, 100, 45, 1),
        new Color32 (118, 73, 41, 1),
        new Color32 (60, 73, 55, 1))
    );
    _tex.filterMode = FilterMode.Trilinear;
    _tex.wrapMode = TextureWrapMode.Clamp;
    _tex.Apply ();

    //Pass _tex to the material
    _rend.material.SetTexture ("_RampTex", _tex);
}

//Returns a Color32 array of specified colors
private Color32[] StarGradient(Color32 a, Color32 b, Color32 c, Color32 d) {
    Color32[] _colors = new Color32[4];
    _colors [0] = a;
    _colors [1] = b;
    _colors [2] = c;
    _colors [3] = d;
    return _colors;
}

SubShader {
     Tags {"Queue"="Background"  "IgnoreProjector"="True"}
     LOD 100

     ZWrite On

     Pass {
     CGPROGRAM
     #pragma vertex vert
     #pragma fragment frag
     #include "UnityCG.cginc"

     fixed4 _ColorTop;
     fixed4 _ColorMidTop;
     fixed4 _ColorMidBot;
     fixed4 _ColorBot;

      float  _MiddleBot;
      float  _MiddleTop;

     struct v2f {
         float4 pos : SV_POSITION;
         float4 texcoord : TEXCOORD0;
     };

     v2f vert (appdata_full v) {
         v2f o;
         o.pos = UnityObjectToClipPos (v.vertex);
         o.texcoord = v.texcoord;
         return o;
     }

     fixed4 frag (v2f i) : COLOR {

         fixed4 c = lerp(_ColorBot, _ColorMidBot, i.texcoord.y / _MiddleBot) * step(i.texcoord.y, _MiddleBot);
         c += lerp(_ColorMidBot, _ColorMidTop, (i.texcoord.y - _MiddleBot) /(_MiddleTop - _MiddleBot) ) * step(_MiddleBot,i.texcoord.y) * step(i.texcoord.y,_MiddleTop);
         c += lerp(_ColorMidTop, _ColorTop, (i.texcoord.y - _MiddleTop) / (1 - _MiddleTop)) * step(_MiddleTop, i.texcoord.y);
         c.a = 1;

         return c;
     }
     ENDCG
     }
 }