shaders/cgshaderfractal/Mandelbrot.cg

// Based on the example code by Arkadiusz Waliszewski (arsil@acm.org).
//----------------------------------------------------------------------------

struct vert2frag 
{
    float4 HPosition    : HPOS;
    float2 ScreenCoords : TEX0;
};

struct frag2screen
{
    float3 COL : COLOR;
};

frag2screen main(vert2frag In)
{
    frag2screen Out;

    float KillValue = 8.0;

    float4 Color    = float4(0   ,    0,     0,    0);
    float4 ColorAdd = float4(0.01, 0.01, 0.015, 0.01);

    float2 AB = float2(0, 0);

    float2 ABSrt;

    for( int i = 0; i < 64; i++ )
    {
        ABSrt = AB * AB;
        AB = float2(ABSrt.x - ABSrt.y - In.ScreenCoords.x,  2 * AB.x * AB.y + In.ScreenCoords.y);
        if ((ABSrt.x + ABSrt.x) < KillValue)
        {
            Color += ColorAdd;
        }
    }

    Out.COL = Color.xyz;

    return Out;
}