Different behavious of shader in unity's build in simulator and ios device

Hello

I am trying to draw object on plane , i have used the shader . shader is working fine on Unit's simulator but when i make a build for ios device and run that code on device object on plane is not being drawn properly . Below is the shader i am using .Anyone having idea, whats wrong ?

Shader "GLSL planar shadow_Texture" { Properties {

   _ShadowTex ("Shadow Image", 2D) = "white" {} 
   
   }

SubShader { Tags { "Queue" = "Transparent" }

   Pass {   
      Tags { "LightMode" = "ForwardBase" } 


          
         // rendering of projected shadow
      Offset -1.0, -2.0 
      
      ZWrite Off // don't occlude other objects
      Blend SrcAlpha OneMinusSrcAlpha
     
         // make sure shadow polygons are on top of shadow receiver
         
 
      GLSLPROGRAM
      
      uniform sampler2D _ShadowTex;  
 
      varying vec4 textureCoordinates_shadow; 
 
      // User-specified uniforms
      uniform vec4 _ShadowColor;
      uniform mat4 _World2Receiver; // set by script
          
          
      uniform vec3 _WorldSpaceCameraPos; 

// // camera position in world space // uniform mat4 _Object2World; // model matrix // uniform mat4 _World2Object; // inverse model matrix // // (apart from the factor unity_Scale.w)

      varying vec3 varyingNormalDirection; 
         // normalized surface normal vector
      varying vec3 varyingViewDirection; 
         // normalized view direction 
         
         
      // The following built-in uniforms ) 
      // are also defined in "UnityCG.glslinc", 
      // i.e. one could #include "UnityCG.glslinc" 
      uniform mat4 _Object2World; // model matrix
      uniform mat4 _World2Object; // inverse model matrix
      uniform vec4 unity_Scale; // w = 1/uniform scale; 
         // should be multiplied to _World2Object 
      uniform vec4 _WorldSpaceLightPos0; 
         // position or direction of light source
 
      #ifdef VERTEX
 
      void main()
      {            
      
          textureCoordinates_shadow = gl_MultiTexCoord0;
          
         mat4 modelMatrix = _Object2World;
         mat4 modelMatrixInverse = _World2Object * unity_Scale.w;
         modelMatrixInverse[3][3] = 1.0; 
         mat4 viewMatrix = gl_ModelViewMatrix * modelMatrixInverse;
         
         //  soft shadow 
         varyingNormalDirection = normalize(
            vec3(vec4(gl_Normal, 0.0) * modelMatrixInverse));
         varyingViewDirection = normalize(_WorldSpaceCameraPos 
            - vec3(modelMatrix * gl_Vertex));
         
 
         vec4 lightDirection;
         if (0.0 != _WorldSpaceLightPos0.w) 
         {
            // point or spot light
            lightDirection = normalize(
               modelMatrix * gl_Vertex - _WorldSpaceLightPos0);
         } 
         else 
         {
            // directional light
            lightDirection = -normalize(_WorldSpaceLightPos0); 
         }
 
         vec4 vertexInWorldSpace = modelMatrix * gl_Vertex;
         vec4 world2ReceiverRow1 = 
            vec4(_World2Receiver[0][1], _World2Receiver[1][1], 
            _World2Receiver[2][1], _World2Receiver[3][1]);
         float distanceOfVertex = 
            dot(world2ReceiverRow1, vertexInWorldSpace); 
            // = (_World2Receiver * vertexInWorldSpace).y 
            // = height over plane 
         float lengthOfLightDirectionInY = 
            dot(world2ReceiverRow1, lightDirection); 
            // = (_World2Receiver * lightDirection).y 
            // = length in y direction
 
         if (distanceOfVertex > 0.0 && lengthOfLightDirectionInY < 0.0)
         {
            lightDirection = lightDirection 
               * (distanceOfVertex / (-lengthOfLightDirectionInY));
         }
         else
         {
            lightDirection = vec4(0.0, 0.0, 0.0, 0.0); 
               // don't move vertex
         }
 
         gl_Position = gl_ProjectionMatrix * (viewMatrix 
            * (vertexInWorldSpace + lightDirection));
      }
 
      #endif
 
      #ifdef FRAGMENT
 
      void main()
      {
          
          
      
          
          gl_FragColor = 
            texture2D(_ShadowTex, vec2(textureCoordinates_shadow));
          

// gl_FragColor = _ShadowColor;

      }
 
      #endif
 
      ENDGLSL
   }

} }