out vec4 FragColor;
uniform sampler2D uTexMain;
uniform sampler2D uTexMotion;
uniform float uBlurStrength;

in vec2 aUv;

vec2 rand_hash22( vec2 p )
{
   vec3 p3 = fract(vec3(p.xyx) * 213.8976123);
   p3 += dot(p3, p3.yzx+19.19);
   return fract(vec2((p3.x + p3.y)*p3.z, (p3.x+p3.z)*p3.y));
}

void main()
{
   vec2 vcenter = (aUv-vec2(0.5))*vec2(2.0);
   vec2 vrand = rand_hash22( aUv ) * 2.0 - vec2(1.0);
   vec2 vrand1 = rand_hash22( vrand ) * 2.0 - vec2(1.0);
   
   vec2 vdir = texture( uTexMotion, aUv ).xy * uBlurStrength;

   vec4 vcolour0 = texture( uTexMain, aUv + vdir*vrand.x );
   vec4 vcolour1 = texture( uTexMain, aUv + vdir*vrand.y );
   vec4 vcolour2 = texture( uTexMain, aUv + vdir*vrand1.x );
   vec4 vcolour3 = texture( uTexMain, aUv + vdir*vrand1.y );

   FragColor = ( vcolour0 + vcolour1 + vcolour2 + vcolour3 ) * 0.25;
}