Making shader not ignore Light on transparent areas ?

Hello, i need this shader to ignore light just where the actually is no transparency on a sprite. Right now it ignores light for the full sprite size like 16x16, you can see that the light is blocked in the screenshot.

How i do it right now is to add a custom outline to everysprite pixel by pixel with the sprite editor and that is consuming a huge amount of time.

How can i get this shader to not ignore the lighting on transparent areas ? But it should ignore lighting at the filled areas, where the beam is for example.

Thank you for your time!

Justin

 Shader "Custom/BloomShader"
 {
 
     Properties
     {
 
 
         [PerRendererData] _MainTex ("Sprite Texture", 2D) = "white" {}
         _Color ("Tint", Color) = (1,1,1,1)
         [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
         _BloomThreshold ("BloomThreshold", Float) = 2.5
     }
 
     SubShader
     {
         Tags
         { 
             "Queue"="Transparent" 
             "IgnoreProjector"="True" 
             "RenderType"="Transparent" 
             "PreviewType"="Plane"
             "CanUseSpriteAtlas"="True"
         }
 
         Cull Off
         Lighting Off
         ZWrite Off
         Blend One OneMinusSrcAlpha
 
         Pass
         {
         CGPROGRAM
 
         //    #pragma surface surf Lambert alpha
 
             #pragma vertex vert
             #pragma fragment frag
             #pragma target 2.0
             #pragma multi_compile _ PIXELSNAP_ON
             #pragma multi_compile _ ETC1_EXTERNAL_ALPHA
             #include "UnityCG.cginc"
             
             struct appdata_t
             {
                 float4 vertex   : POSITION;
                 float4 color    : COLOR;
                 float2 texcoord : TEXCOORD0;
             };
 
             struct v2f
             {
                 float4 vertex   : SV_POSITION;
                 fixed4 color    : COLOR;
                 float2 texcoord  : TEXCOORD0;
             };
             
             fixed4 _Color;
             fixed _BloomThreshold;
 
             v2f vert(appdata_t IN)
             {
                 v2f OUT;
                 OUT.vertex = UnityObjectToClipPos(IN.vertex);
                 OUT.texcoord = IN.texcoord;
 
                 OUT.color = IN.color * _Color;
                 #ifdef PIXELSNAP_ON
                 OUT.vertex = UnityPixelSnap (OUT.vertex);
                 #endif
 
                 return OUT;
             }
 
             sampler2D _MainTex;
             sampler2D _AlphaTex;
 
             // http://theorangeduck.com/page/avoiding-shader-conditionals
             fixed when_gt(fixed x, fixed y) {
               return max(sign(x - y), 0.0);
             }
 
             fixed4 SampleSpriteTexture (float2 uv)
             {
                 fixed4 color = tex2D (_MainTex, uv);
 
 #if ETC1_EXTERNAL_ALPHA
                 // get the color from an external texture (usecase: Alpha support for ETC1 on android)
                 color.a = tex2D (_AlphaTex, uv).r;
 #endif //ETC1_EXTERNAL_ALPHA
 
                 return color;
             }
 
             fixed4 frag(v2f IN) : SV_Target
             {
                 fixed4 tex = SampleSpriteTexture (IN.texcoord);
                 fixed4 c = tex * IN.color;
                 c += 1 * when_gt(tex.r + tex.g +tex.b , _BloomThreshold); // if r+g+b > threshold, then make this color brighter than 1
                 c.rgb *= c.a;
                 return c;
             }
         ENDCG
         }
     }
 }