stk-code_catmod/data/shaders/ssao.frag

66 lines
2.3 KiB
GLSL
Raw Normal View History

2014-05-12 12:39:33 -04:00
// From paper http://graphics.cs.williams.edu/papers/AlchemyHPG11/
// and improvements here http://graphics.cs.williams.edu/papers/SAOHPG12/
uniform sampler2D dtex;
2015-01-12 16:47:53 -05:00
uniform float radius;
2016-06-28 15:55:51 -04:00
uniform float k;
uniform float sigma;
2014-05-12 12:39:33 -04:00
out float AO;
const float tau = 7.;
2014-07-16 18:12:54 -04:00
const float beta = 0.002;
2014-05-12 12:39:33 -04:00
const float epsilon = .00001;
#define SAMPLES 16
2016-06-28 15:55:51 -04:00
const float invSamples = 0.0625; // 1. / SAMPLES
2014-05-12 12:39:33 -04:00
vec3 getXcYcZc(int x, int y, float zC)
{
// We use perspective symetric projection matrix hence P(0,2) = P(1, 2) = 0
2016-06-28 15:55:51 -04:00
float xC= (2. * (float(x)) / screen.x - 1.) * zC / ProjectionMatrix[0][0];
float yC= (2. * (float(y)) / screen.y - 1.) * zC / ProjectionMatrix[1][1];
return vec3(xC, yC, zC);
}
2014-05-12 12:39:33 -04:00
void main(void)
{
vec2 uv = gl_FragCoord.xy / screen;
float lineardepth = textureLod(dtex, uv, 0.).x;
int x = int(gl_FragCoord.x), y = int(gl_FragCoord.y);
vec3 FragPos = getXcYcZc(x, y, lineardepth);
2014-05-12 12:39:33 -04:00
// get the normal of current fragment
vec3 ddx = dFdx(FragPos);
vec3 ddy = dFdy(FragPos);
vec3 norm = normalize(cross(ddy, ddx));
2014-05-12 12:39:33 -04:00
float r = radius / FragPos.z;
2016-06-28 15:55:51 -04:00
float phi = 3. * float((x ^ y) + x * y);
2014-05-12 12:39:33 -04:00
float bl = 0.0;
2016-06-28 15:55:51 -04:00
float m = log2(r) + 6. + log2(invSamples);
2014-05-12 12:39:33 -04:00
float theta = 2. * 3.14 * tau * .5 * invSamples + phi;
vec2 rotations = vec2(cos(theta), sin(theta)) * screen;
vec2 offset = vec2(cos(invSamples), sin(invSamples));
2014-05-12 12:39:33 -04:00
for(int i = 0; i < SAMPLES; ++i) {
2016-06-28 15:55:51 -04:00
float alpha = (float(i) + .5) * invSamples;
rotations = vec2(rotations.x * offset.x - rotations.y * offset.y, rotations.x * offset.y + rotations.y * offset.x);
2014-05-12 12:39:33 -04:00
float h = r * alpha;
2015-01-12 16:47:53 -05:00
vec2 localoffset = h * rotations;
2014-05-12 12:39:33 -04:00
m = m + .5;
2015-01-12 16:47:53 -05:00
ivec2 ioccluder_uv = ivec2(x, y) + ivec2(localoffset);
2014-05-12 12:39:33 -04:00
2016-06-28 15:55:51 -04:00
if (ioccluder_uv.x < 0 || ioccluder_uv.x > int(screen.x) || ioccluder_uv.y < 0 || ioccluder_uv.y > int(screen.y)) continue;
2014-05-12 12:39:33 -04:00
2015-01-12 16:47:53 -05:00
float LinearoccluderFragmentDepth = textureLod(dtex, vec2(ioccluder_uv) / screen, max(m, 0.)).x;
vec3 OccluderPos = getXcYcZc(ioccluder_uv.x, ioccluder_uv.y, LinearoccluderFragmentDepth);
2014-05-12 12:39:33 -04:00
vec3 vi = OccluderPos - FragPos;
2016-06-28 15:55:51 -04:00
bl += max(0., dot(vi, norm) - FragPos.z * beta) / (dot(vi, vi) + epsilon);
2014-05-12 12:39:33 -04:00
}
2015-01-12 14:13:11 -05:00
AO = max(pow(1.0 - min(2. * sigma * bl * invSamples, 0.99), k), 0.);
2015-01-12 14:04:39 -05:00
}