//-----------------------------------------------------------------------------
//GLSL
//-----------------------------------------------------------------------------
[vert.glsl]

#version 120

attribute vec2 in_Position;

uniform vec2 in_screen_res;

uniform float in_step;
varying vec2 pass_pos;
varying vec2 pass_p[8];

void main()
{
    //JFA ALGO
    pass_pos = ((vec2(1.0) + in_Position) * 0.5);

    float k = in_step;

    vec2 p2 = pass_pos;
    pass_p[0] = p2 + vec2(-k, -k);
    pass_p[1] = p2 + vec2( 0, -k);
    pass_p[2] = p2 + vec2( k, -k);
    pass_p[3] = p2 + vec2(-k,  0);
    pass_p[4] = p2 + vec2( k,  0);
    pass_p[5] = p2 + vec2(-k,  k);
    pass_p[6] = p2 + vec2( 0,  k);
    pass_p[7] = p2 + vec2( k,  k);

    gl_Position = vec4(in_Position, 0.0, 1.0);
}

[frag.glsl]

#version 120

#if defined GL_ES
precision highp float;
#endif

uniform sampler2D in_texture;

varying vec2 pass_pos;
varying vec2 pass_p[8];

void main(void)
{
    vec4 src_color = texture2D(in_texture, pass_pos);
    vec4 neigh_color;

    for (int i = 0; i < 8; ++i)
    {
        neigh_color = texture2D(in_texture, pass_p[i]);

        if (neigh_color.z > 0.0 && src_color.z == 0.0)
            src_color = neigh_color;
        else if (neigh_color.z > 0.0 && src_color.z > 0.0 &&
                 length(neigh_color.xy - pass_pos) < length(src_color.xy - pass_pos))
            src_color = neigh_color;

    }

    gl_FragColor = src_color;
}

//-----------------------------------------------------------------------------
//HLSL
//-----------------------------------------------------------------------------
[vert.hlsl]

void main(float2 in_Position : POSITION,
          out float2 pass_Position : TEXCOORD0,
          out float4 out_Position : POSITION)
{
    pass_Position = in_Position;
    out_Position = float4(in_Position, 0.0, 1.0);
}

[frag.hlsl]

void main(in float2 pass_Position : TEXCOORD0,
          uniform sampler2D in_Texture,
          uniform float in_Flag,
          uniform float3 in_Point,
          uniform float3 in_Color,
          out float4 out_FragColor : COLOR)
{
    out_FragColor = float4(0.0);
}