uniform float4x4 ViewProj;
uniform texture2d image;

uniform float2 tex_size;
uniform int range;
uniform float4 glow_color;

sampler_state def_sampler {
	Filter   = Linear;
	AddressU = Clamp;
	AddressV = Clamp;
};

struct VertInOut {
	float4 pos : POSITION;
	float2 uv  : TEXCOORD0;
};

VertInOut VSDefault(VertInOut vert_in)
{
	VertInOut vert_out;
	vert_out.pos = mul(float4(vert_in.pos.xyz, 1.0), ViewProj);
	vert_out.uv  = vert_in.uv;
	return vert_out;
}

float4 OuterGlow(float2 uv)
{
        float radiusX = 1 / tex_size.x;
        float radiusY = 1 / tex_size.y;
        float inner = 0;
        float outter = 0;
        int count = 0;
        for (int k = -range; k <= range; ++k)
        {
                for (int j = -range; j <= range; ++j)
                {
			float4 m = image.Sample(def_sampler, float2(uv.x + k * radiusX , uv.y + j * radiusY));
			outter += 1 - m.a;
			inner += m.a;
			count += 1;
                }
        }
        inner /= count;
        outter /= count;

	float4 v_color =  float4(1.0, 1.0, 1.0, 1.0);
                
        float4 col = image.Sample(def_sampler, uv) * v_color;
        float out_alpha = max(col.a, inner*2);
	out_alpha = min(1, out_alpha);
        float in_alpha = min(out_alpha, outter);

	if(col.a < 0.9){
		col.rgb = col.rgb + (1-col.a) * 1 * glow_color.a * glow_color.rgb;
		col.a = out_alpha;
	}
        return col;
}

float4 PSOuterFlow(VertInOut vert_in) : TARGET
{
	return OuterGlow(vert_in.uv);
}

technique Draw
{
	pass
	{
		vertex_shader = VSDefault(vert_in);
		pixel_shader  = PSOuterFlow(vert_in);
	}
}