v4k-git-backup/demos/art/fx/fxSSAO.fs

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// based on code by arkano22. See: http://www.gamedev.net/forums/topic/550699-ssao-no-halo-artifacts/
// - rlyeh, public domain
uniform vec2 camerarange = vec2(1.0, 1024.0);
// uniform sampler2D som; // Depth texture (iChannel1)
#if 0
uniform sampler2D rand; // Random texture (iChannel2)
vec2 getRandom(vec2 uv) {
vec3 random = texture2D(rand, uv.st);
return random*2.0-vec3(1.0);
}
#else
#define MOD3 vec3(.1031,.11369,.13787)
float hash12(vec2 p) {
vec3 p3 = fract(vec3(p.xyx) * MOD3);
p3 += dot(p3, p3.yzx + 19.19);
return fract((p3.x + p3.y) * p3.z);
}
vec2 hash22(vec2 p) {
vec3 p3 = fract(vec3(p.xyx) * MOD3);
p3 += dot(p3, p3.yzx+19.19);
return fract(vec2((p3.x + p3.y)*p3.z, (p3.x+p3.z)*p3.y));
}
vec3 getPosition(vec2 uv) {
float fl = textureLod(iChannel0, vec2(0.), 0.).x;
float d = textureLod(iChannel0, uv, 0.).w;
vec2 p = uv*2.-1.;
mat3 ca = mat3(1.,0.,0.,0.,1.,0.,0.,0.,-1./1.5);
vec3 rd = normalize( ca * vec3(p,fl) );
vec3 pos = rd * d;
return pos;
}
vec2 getRandom(vec2 uv) {
return normalize(hash22(uv*126.1231) * 2. - 1.);
}
#endif
float pw = 1.0/iResolution.x*0.5;
float ph = 1.0/iResolution.y*0.5;
float readDepth(in vec2 coord) {
if (coord.x<0||coord.y<0) return 1.0;
float nearZ = camerarange.x;
float farZ =camerarange.y;
float posZ = texture(iChannel1, coord).x;
return (2.0 * nearZ) / (nearZ + farZ - posZ * (farZ - nearZ));
}
float compareDepths(in float depth1, in float depth2,inout int far) {
float diff = (depth1 - depth2)*100; //depth difference (0-100)
float gdisplace = 0.2; //gauss bell center
float garea = 2.0; //gauss bell width 2
//reduce left bell width to avoid self-shadowing
if (diff<gdisplace){
garea = 0.1;
}else{
far = 1;
}
float gauss = pow(2.7182,-2*(diff-gdisplace)*(diff-gdisplace)/(garea*garea));
return gauss;
}
float calcAO(float depth, vec2 uv, float dw, float dh) {
float temp = 0;
float temp2 = 0;
float coordw = uv.x + dw/depth;
float coordh = uv.y + dh/depth;
float coordw2 = uv.x - dw/depth;
float coordh2 = uv.y - dh/depth;
if (coordw < 1.0 && coordw > 0.0 && coordh < 1.0 && coordh > 0.0){
vec2 coord = vec2(coordw , coordh);
vec2 coord2 = vec2(coordw2, coordh2);
int far = 0;
temp = compareDepths(depth, readDepth(coord),far);
//DEPTH EXTRAPOLATION:
if (far > 0){
temp2 = compareDepths(readDepth(coord2),depth,far);
temp += (1.0-temp)*temp2;
}
}
return temp;
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
//randomization texture:
vec2 uv = fragCoord.xy / iResolution.xy;
vec2 random = getRandom( uv + vec2(iTime) );
//initialize stuff:
float depth = readDepth(uv);
float ao = 0.0;
for(int i=0; i<4;++i) {
//calculate color bleeding and ao:
ao+=calcAO(depth, uv, pw, ph);
ao+=calcAO(depth, uv, pw, -ph);
ao+=calcAO(depth, uv, -pw, ph);
ao+=calcAO(depth, uv, -pw, -ph);
ao+=calcAO(depth, uv, pw*1.2, 0);
ao+=calcAO(depth, uv, -pw*1.2, 0);
ao+=calcAO(depth, uv, 0, ph*1.2);
ao+=calcAO(depth, uv, 0, -ph*1.2);
//sample jittering:
pw += random.x*0.0007;
ph += random.y*0.0007;
//increase sampling area:
pw *= 1.7;
ph *= 1.7;
}
//final values, some adjusting:
vec4 texel = texture(iChannel0, uv);
float finalAO = 1.0-(ao/32.0); finalAO = 0.5+finalAO*0.5;
fragColor = vec4(texel.rgb * vec3(finalAO), texel.a);
//fragColor = vec4(vec3(finalAO), texel.a); // << debug
}