/*
 * Copyright 2008 (c) muta
 * 
 * http://unbland.net/
 * http://unbland.net/blog/
 * 
 * Licensed under the MIT License
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
<languageVersion : 1.0;>
kernel RadialBlur
<
    namespace   : "org.unbland";
    vendor      : "muta";
    version     : 1;
>
{
    parameter float2 center
    <
        minValue     : float2(1.0, 1.0);
        maxValue     : float2(4096.0, 4096.0);
        //defaultValue : float2(1.0, 1.0);
        defaultValue : float2(160.0, 160.0);
    >;
    
    parameter float amount
    <
        minValue     : float(1.0);
        maxValue     : float(100.0);
        defaultValue : float(1.0);
    >;
    
    parameter float rotation
    <
        minValue     : float(-90.0);
        maxValue     : float(90.0);
        defaultValue : float(0.0);
    >;
    
    input  image4 source;
    output pixel4 result;

    void evaluatePixel()
    {
        float  numSamples = 9.0;
        float  base = 4.0;
        float2 coord = outCoord();
        float2 dist = coord - center;
        float  radian = atan(dist.y, dist.x) + radians(rotation);
        float  rate = amount / 200.0 * length(dist) / numSamples;
        float2 n = float2(cos(radian), sin(radian));
        
        float  d;
        float2 p;
        float4 c;
        
        float4 color = float4(0.0, 0.0, 0.0, 1.0);
        float  w = 0.0;
        
        d = (0.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (1.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (2.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (3.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (4.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c * 3.0;
            w += 3.0;
        }
        
        d = (5.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (6.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (7.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        d = (8.0 - base) * rate;
        p.x = d * n.x + coord.x;
        p.y = d * n.y + coord.y;
        c = sampleNearest(source, p);
        
        if (c.a != 0.0)
        {
            color += c;
            w += 1.0;
        }
        
        result = color / w;
    }
}