Make black colour in shader white?

[elvisish]

This shader fades between black and transparent, where white is defined as transparent. i'm trying to understand how i could change it so it fades from transparent to white:

sampler2D Texture0;
float time;
float4 a, b;

float STEP = 1/3.0;

float4 ps_main(float2 In : TEXCOORD0) : COLOR0
{ 
    //Source color
    float4 ret = tex2D(Texture0, In);
    float3 fade = 1;

    //Step A: black to A
    if(time < STEP)
    {
        fade *= a.rgb * (time/STEP);
    }
    //Step B: A to B
    else if(time >= STEP && time <= 2*STEP)
    {
        fade = lerp(a.rgb, b.rgb, (time-STEP)/STEP);
    }
    //Step C: B to white
    else if(time < 1)
    {
        fade = 1 - (1-b)*((1-time)/STEP);
    }

    //Apply fade
    ret.rgb *= fade;
    return ret;
}

technique Shader { pass P0 { PixelShader = compile ps_2_0 ps_main(); } }

[FlipSwitchX]

Which shader is this and what effect are you trying to pull off exactly? Because if you want to go from white to transparent you could use another shader called simple mask (pretty sure that's what it's called), forgot the group of shaders it is part of, I'd check for you but I'm on my phone. Anyway with this mask you can easily set it to white and then fade just the shader out, revealing your character is what it's for I'm assuming.

[elvisish]

Here's the full shader in zip: https://www.dropbox.com/s/jwfypapksonoj2k/SonicFade.zip

I still have no idea how to make it go through the colors to white instead of black?

[SHINGEN]

Here's the full shader in zip: https://www.dropbox.com/s/jwfypapksonoj2k/SonicFade.zip

I still have no idea how to make it go through the colors to white instead of black?

Did you ever work it out in the end? If so how did you do it as im looking for the exact same thing. A sonicfade that goes to white instead of black but as a dx11 shader

[elvisish]

Yeah, @fnkycoldmadeanr helped me with this:Attachment 27159 - it's slightly different now in that the amount is the opposite end of the time slider; I've included an example mfa that shows it flashing in and flashing out if you press F.

Unfortunately, I have no idea how to convert it to DX11, I'm afraid! Eventually I'll probably just take the SonicFade regular hlsl and fxc and just mod in the differences.