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/* -------- Utils Functions --------- */
vec2 sample_disk(float nsample, float invsamplenbr)
{
vec3 Xi = hammersley_3d(nsample, invsamplenbr);
float x = Xi.x * Xi.y;
float y = Xi.x * Xi.z;
return vec2(x, y);
}
vec3 sample_hemisphere(float nsample, float invsamplenbr, vec3 N, vec3 T, vec3 B)
{
vec3 Xi = hammersley_3d(nsample, invsamplenbr);
float z = Xi.x; /* cos theta */
float r = sqrt( 1.0f - z*z ); /* sin theta */
float x = r * Xi.y;
float y = r * Xi.z;
Ht = vec3(x, y, z); /* Global variable */
return from_tangent_to_world(Ht, N, T, B);
}
#ifdef USE_SSAO
#if 0 /* Cheap */
float ssao(vec3 viewpos, vec3 viewnor, out float result)
{
float dist = unfssaoparam.z;
setup_noise(gl_FragCoord.xy); /* Noise to dither the samples */
/* get uv of the shading point */
vec4 projvec = gl_ProjectionMatrix * vec4(viewpos, 1.0);
vec2 uv = (projvec.xy / projvec.w) * 0.5 + 0.5;
vec2 offset;
offset.x = gl_ProjectionMatrix[0][0] * dist / projvec.w;
offset.y = gl_ProjectionMatrix[1][1] * dist / projvec.w;
/* convert from -1.0...1.0 range to 0.0..1.0 for easy use with texture coordinates */
offset *= 0.5;
float factor = 0.0;
/* We don't need as much samples for ssao */
for (float i = 0; i < unfssaoparam.x; i++) {
vec2 Xi = sample_disk(i, 1/unfssaoparam.x);
vec2 uvsample = uv + Xi * offset;
if (uvsample.x > 1.0 || uvsample.x < 0.0 || uvsample.y > 1.0 || uvsample.y < 0.0)
continue;
float sampledepth = frontface_depth(ivec2(uvsample * unfclip.zw));
/* Background Case */
if (sampledepth == 1.0)
continue;
vec3 samplepos = position_from_depth(uvsample, sampledepth);
vec3 dir = samplepos - viewpos;
float len = length(dir);
float f = dot(dir, viewnor);
/* use minor bias here to cancel self shadowing */
if (f > 0.05 * len + 0.0001)
factor += f / (len + len * len * len);
}
result = saturate(1.0 - factor / unfssaoparam.x);
}
#else /* Expensive */
void ssao(vec3 viewpos, vec3 viewnor, out float result)
{
float dist = unfssaoparam.z;
setup_noise(gl_FragCoord.xy); /* Noise to dither the samples */
vec3 T;
make_orthonormals(viewnor, T, B); /* Generate tangent space */
float homcoord = (gl_ProjectionMatrix[3][3] == 0.0) ? gl_ProjectionMatrix[2][3] * viewpos.z : dist;
float factor = 0.0;
float weight = 0.0;
for (float i = 0; i < unfssaoparam.x; i++) {
vec3 Xi = sample_hemisphere(i, 1/unfssaoparam.x, viewnor, T, B);
float pdf = dot(Xi, viewnor);
weight += pdf;
/* Raymarch */
/* We jitter the starting position by a percentage of the normal
* offset to a v o i d banding artifact for thin objects but
* we still finish at the same final position to a v o i d
* less sampling at the edges of the occlusion effect */
vec3 offset = dist * Xi / unfssaoparam.y;
vec3 ray = (jitternoise.y - 0.5) * -offset;
vec3 endoffset = offset - ray;
for (float j = unfssaoparam.y; j > 0.0; j--) {
ray += (j == 1) ? endoffset : offset;
vec4 co = unfpixelprojmat * vec4(ray + viewpos, 1.0);
co.xy /= co.w;
/* Discard ray leaving screen */
if (co.x > unfclip.z || co.x < 0.0 || co.y > unfclip.w || co.y < 0.0)
break;
float sampledepth = frontface_depth(ivec2(co.xy), 0);
/* Background Case */
if (sampledepth == 1.0)
continue;
/* We have a hit */
if (sampledepth > ray.z + viewpos.z + homcoord * 0.002
#ifdef USE_BACKFACE
&& backface_depth(ivec2(co.xy), 0) < ray.z + viewpos.z
#endif
)
{
factor += pdf;
break;
}
}
}
result = saturate(1.0 - (factor / weight) * unfssaoparam.w);
}
#endif
#else
void ssao(vec3 viewpos, vec3 viewnor, out float result)
{
result = 1.0;
}
#endif
/* -------- BSDF --------- */
/* -------- Preview Lights --------- */
/* -------- Physical Lights --------- */
/* -------- Image Based Lighting --------- */
void env_sampling_ambient_occlusion(
float pbr, vec3 viewpos, mat4 invviewmat, mat4 viewmat,
vec3 N, vec3 T, float roughness, float ior, float sigma,
float toon_size, float toon_smooth, float anisotropy, float aniso_rotation,
float ao_factor, out vec3 result)
{
result = vec3(ao_factor);
}
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