I want to fade out this Texture Masking Shader (using Rendertextures) and I need your help

Question

So I just spent more than 8 hours researching on Google, Answers, Stackoverflow etc. why this wouldn't work, to no avail:

I followed this tutorial here: http://studio.openxcell.com/remove-dustfog-object-unity-swipe.html

I used the instructions and shaders in there to make this "dust cleaning" effect work - but I have a problem fading out the image. Here's what I tried to do, in Properties I added an _Alpha Property as a Float:

     Properties {
         _MainTex ("Main", 2D) = "white" {}
         _MaskTex ("Mask", 2D) = "white" {}
         _Alpha ("Alpha", Float) = 0.5
     }

Then I would try to insert that _Alpha Variable into this line of code (instead of the "1.0" that was there previously):

             fixed4 frag(vert2frag input) : COLOR
             {
                 fixed4 main_color = tex2D(_MainTex, input.texcoord);
                 fixed4 mask_color = tex2D(_MaskTex, input.texcoord);
                 fixed4 _Alpha;
                 
                 return fixed4(main_color.r, main_color.g, main_color.b, main_color.a * (_Alpha - mask_color.a));
             }

So far so good, but instead of letting me change the Alpha Channel of the Texture it produces a strange "flickering" of the image on Mac, and on Windows it gives me this error:

Shader error in 'TextureMasking': incorrect number of arguments to numeric-type constructor at line 52 (on d3d11)

I really need help, I want a dust-cleaning effect for my sprites but also want to alpha-fade this. It seems like NO one has done this before (which seems strange) and I can't find anything on the Asset Store (I would gladly pay for it at this point).

Can anyone help?

Answer 1

Answer by illogicalcrow · Mar 10, 2015 at 09:51 PM

Pretty sure you have 'fixed4 _Alpha' in your frag shader when it shouldn't be. 'uniform float _Alpha' should be somewhere just under CGPROGRAM outside of the functions/structs and you'll be able to access the property in the frag function without issue.

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kbm · Mar 10, 2015 at 11:19 PM 0

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Thanks for your reply. Unfortunately, when I put the "fixed4 _Alpha" underneath CGPROGRA$$anonymous$$ like this:

 Shader "Texture$$anonymous$$asking" {
     Properties {
         _$$anonymous$$ainTex ("$$anonymous$$ain", 2D) = "white" {}
         _$$anonymous$$askTex ("$$anonymous$$ask", 2D) = "white" {}
         _Alpha ("Alpha", Float) = 0.5
     }
 
     SubShader {
         Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
         ZWrite Off
         ZTest Off
         Blend SrcAlpha One$$anonymous$$inusSrcAlpha
         Pass {
             CGPROGRA$$anonymous$$
             #pragma vertex vert
             #pragma fragment frag
             #pragma fragmentoption ARB_precision_hint_fastest
             #include "UnityCG.cginc"
 
             uniform sampler2D _$$anonymous$$ainTex;
             uniform sampler2D _$$anonymous$$askTex;
             uniform float4 _$$anonymous$$ainTex_ST;
             uniform float4 _$$anonymous$$askTex_ST;
             uniform fixed4 _Alpha;
 
             struct app2vert
             {
                 float4 position: POSITION;
                 float2 texcoord: TEXCOORD0;
             };
 
             struct vert2frag
             {
                 float4 position: POSITION;
                 float2 texcoord: TEXCOORD0;
             };
 
             vert2frag vert(app2vert input)
             {
                 vert2frag output;
                 output.position = mul(UNITY_$$anonymous$$ATRIX_$$anonymous$$VP, input.position);
                 output.texcoord = TRANSFOR$$anonymous$$_TEX(input.texcoord, _$$anonymous$$ainTex);
                 return output;
             }
             
             fixed4 frag(vert2frag input) : COLOR
             {
                 fixed4 main_color = tex2D(_$$anonymous$$ainTex, input.texcoord);
                 fixed4 mask_color = tex2D(_$$anonymous$$askTex, input.texcoord);
                 
                 return fixed4(main_color.r, main_color.g, main_color.b, main_color.a * (_Alpha - mask_color.a));
             }
             
             ENDCG
         }
     }
 }

It gives me an error:

Shader error in 'Texture$$anonymous$$asking': incorrect number of arguments to numeric-type constructor at line 52 (on d3d11)

It seems to only accept the _Alpha variable when it's inside the frag, but then it's bugging out..

Answer 2

Answer by kbm · Mar 11, 2015 at 02:38 PM

Alright, I solved it:

Instead of

 uniform fixed4 _Alpha;

I needed to write

 uniform float _Alpha;

Thanks for your help! :)

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Answer 3

Answer by Cloggin · May 18, 2017 at 11:08 AM

Found a PDF of the original tutorial - which is no longer available at that link: http://www.bitong-wang.com/wp-content/uploads/2016/03/DustRemoveEffect.pdf

Also, the Wayback Machine has the original page, minus a few graphics: https://web.archive.org/web/20160911073339/http://studio.openxcell.com/remove-dustfog-object-unity-swipe.html

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I want to fade out this Texture Masking Shader (using Rendertextures) and I need your help

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