#include "shaders/utilityLib/fragDeferredRead.glsl"

uniform sampler2D randomBuf; //A buffer to an image containing random directions.
uniform vec2 frameBufSize;
varying vec2 texCoords;

vec2 getRandom(vec2 coord)
{
  float randBufSize = 64.0;
  return normalize(texture2D(randomBuf, frameBufSize * coord / randBufSize).xy * 2.0 - 1.0);
}

float doAmbientOcclusion(vec2 tcoord, vec2 uv, vec3 p, vec3 cnorm)
{
  float g_scale = 5.5;
  float g_bias = .02;
  float g_intensity = 5.5;
  vec3 diff = getPos(tcoord+uv)-p;
  vec3 v = normalize(diff);
  float d = length(diff)*g_scale;
 
  return max(0.0, dot(cnorm, v)-g_bias)*(1.0/(1.0+d))*g_intensity;
}

void main( void )
{
  vec2 vec[8];
  vec[0] = vec2(1,0);
  vec[1] = vec2(-1,0);
  vec[2] = vec2(0,1);
  vec[3] = vec2(0,-1);
  vec[4] = vec2(.707, .707);
  vec[5] = vec2(-.707, .707);
  vec[6] = vec2(.707, -.707);
  vec[7] = vec2(-.707, -.707);

  vec3 p = getPos(texCoords);
  vec3 n = getNormal(texCoords);
  vec2 rand = getRandom(texCoords);

  float ao = 0.0;
  float rad = 0.25/p.z;

  int iterations = 4; //Larger this value the higher the quality.
  for (int j=0; j < iterations; ++j) {
    vec2 coord1 = reflect(vec[j], rand)*rad;
    vec2 coord2 = vec2(coord1.x*.707 - coord1.y*0.707,
                       coord1.x*.707 + coord1.y*.707);
    ao += doAmbientOcclusion(texCoords, coord1*.25, p, n);
    ao += doAmbientOcclusion(texCoords, coord1*.5, p, n);
    ao += doAmbientOcclusion(texCoords, coord1*.75, p, n);
    ao += doAmbientOcclusion(texCoords, coord1*1., p, n);
  }
  ao /= iterations*4.0;
  ao = 1-clamp(ao, 0, 1);
  gl_FragColor = vec4(ao, ao, ao, 1);
}

uniform sampler2D buf0;
uniform vec2 frameBufSize;
varying vec2 texCoords;

void main( void )
{
  float blur[7]; //This vector represents some blur distribution. The one bellow is made up.
  blur[0] = 1;
  blur[1] = 1;
  blur[2] = 2;
  blur[3] = 3;
  blur[4] = 2;
  blur[5] = 1;
  blur[6] = 1;
  float dev = 11.0;
  float width = 3.5;

  vec4 outCol = vec4(0.0, 0.0, 0.0, 0.0);
  for (int i = 0; i < 7; ++i ) {
    outCol += texture2D(buf0, texCoords+vec2(width*(i-3), 0)/frameBufSize)/dev*blur[i];
  }
  gl_FragColor = outCol;
}