Ambient Occlusion

uniform sampler2D Depthmap;
uniform mat4 cam_view;
uniform mat4 cam_proj;

const float Radius = 4.;
const float Samples = 8.;

varying vec3 v_vPosition;
varying vec2 v_vTexcoord;
varying vec3 v_vNormal;
/////////////////////Hash/////////////////////////////////
vec3 Hash3(vec3 pp)
{
	return normalize(fract(cos(pp*mat3(94.55,-69.38,-89.27,78.69,-34.54,23.67,-68.45,90.13,-57.85))*825.79)-.5);
}
//////////////////Color To Depth//////////////////////////
float ColorToDepth(vec4 map)
{	
	return (map.r + (map.g / 256.) + (map.b / 65536.)) * 1000.;
}
//////////////////Camera Position//////////////////////////
vec3 CameraPosition(mat4 view)
{
    float camX = - (view[3][0] * view[0][0] + view[3][1] * view[0][1] + view[3][2] * view[0][2]);
    float camY = - (view[3][0] * view[1][0] + view[3][1] * view[1][1] + view[3][2] * view[1][2]);
    float camZ = - (view[3][0] * view[2][0] + view[3][1] * view[2][1] + view[3][2] * view[2][2]);
	
	return vec3( camX, camY, camZ );
}
//////////////////World To Screen/////////////////////////
vec2 WorldToScreen(vec3 pos, mat4 proj, mat4 view) 
{
	float bound = view[0][2] * pos.x + view[1][2] * pos.y + view[2][2] * pos.z + view[3][2];
	
    if (bound < 0.) { return vec2(-1., -1.); }
	
    float cx = proj[2][0]+proj[0][0]*(view[0][0] * pos.x + view[1][0] * pos.y + view[2][0] * pos.z + view[3][0])/bound;
    float cy = proj[2][1]+proj[1][1]*(view[0][1] * pos.x + view[1][1] * pos.y + view[2][1] * pos.z + view[3][1])/bound;

    return vec2( .5 + .5 * cx, .5 + .5 * cy );
}
///////////////////////////////////////////////////////////////
void main()
{
	float ao = 0.;
	float bias = 0.001;
	
	vec3 camPosition = CameraPosition( cam_view );
	
    for(float i = 1.; i < 360.; i+=(360./Samples))
	{ 
		for( float j = -90.; j < 90.; j += (180./Samples))
		{
		float R = cos(radians(i)) * -sin(radians(j));
		
		vec3 Noise = Hash3( v_vPosition - (R * Radius));
		
		float D = distance( v_vPosition - (Noise * Radius), camPosition );
		
		vec2 coords = WorldToScreen( v_vPosition - (Noise * Radius), cam_proj, cam_view );
		
		float Sample_Depth = ColorToDepth( texture2D( Depthmap, coords) ) + bias;

		ao += (sign(floor(Sample_Depth / D))) / (Samples*10.);
		}
    }
	ao = clamp(ao/0.5, 0.,1.);
    gl_FragColor = vec4(ao,ao,ao,1.);
}