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#define NO_OBJECT_ID uint(0)
#define EPSILON 0.00001
#define M_PI 3.14159265358979323846
/* 4x4 bayer matrix prepared for 8bit UNORM precision error. */
#define P(x) (((x + 0.5) * (1.0 / 16.0) - 0.5) * (1.0 / 255.0))
const vec4 dither_mat4x4[4] = vec4[4](
vec4( P(0.0), P(8.0), P(2.0), P(10.0)),
vec4(P(12.0), P(4.0), P(14.0), P(6.0)),
vec4( P(3.0), P(11.0), P(1.0), P(9.0)),
vec4(P(15.0), P(7.0), P(13.0), P(5.0))
);
float bayer_dither_noise() {
ivec2 tx1 = ivec2(gl_FragCoord.xy) % 4;
ivec2 tx2 = ivec2(gl_FragCoord.xy) % 2;
return dither_mat4x4[tx1.x][tx1.y];
}
/* From http://aras-p.info/texts/CompactNormalStorage.html
* Using Method #4: Spheremap Transform */
vec3 normal_decode(vec2 enc)
{
vec2 fenc = enc.xy * 4.0 - 2.0;
float f = dot(fenc, fenc);
float g = sqrt(1.0 - f / 4.0);
vec3 n;
n.xy = fenc*g;
n.z = 1 - f / 2;
return n;
}
/* From http://aras-p.info/texts/CompactNormalStorage.html
* Using Method #4: Spheremap Transform */
vec2 normal_encode(vec3 n)
{
float p = sqrt(n.z * 8.0 + 8.0);
return vec2(n.xy / p + 0.5);
}
void fresnel(vec3 I, vec3 N, float ior, out float kr)
{
float cosi = clamp(dot(I, N), -1.0, 1.0);
float etai = 1.0;
float etat = ior;
if (cosi > 0) {
etat = 1.0;
etai = ior;
}
// Compute sini using Snell's law
float sint = etai / etat * sqrt(max(0.0, 1.0 - cosi * cosi));
// Total internal reflection
if (sint >= 1) {
kr = 1;
}
else {
float cost = sqrt(max(0.0, 1.0 - sint * sint));
cosi = abs(cosi);
float Rs = ((etat * cosi) - (etai * cost)) / ((etat * cosi) + (etai * cost));
float Rp = ((etai * cosi) - (etat * cost)) / ((etai * cosi) + (etat * cost));
kr = (Rs * Rs + Rp * Rp) / 2;
}
// As a consequence of the conservation of energy, transmittance is given by:
// kt = 1 - kr;
}
vec4 calculate_transparent_accum(vec4 premultiplied) {
float a = min(1.0, premultiplied.a) * 8.0 + 0.01;
float b = -gl_FragCoord.z * 0.95 + 1.0;
float w = clamp(a * a * a * 1e8 * b * b * b, 1e-2, 3e2);
return premultiplied * w;
}
vec3 view_vector_from_screen_uv(vec2 uv, vec4 viewvecs[3], mat4 proj_mat)
{
return (proj_mat[3][3] == 0.0)
? normalize(viewvecs[0].xyz + vec3(uv, 0.0) * viewvecs[1].xyz)
: vec3(0.0, 0.0, 1.0);
}
vec2 matcap_uv_compute(vec3 I, vec3 N, bool flipped)
{
/* Quick creation of an orthonormal basis */
float a = 1.0 / (1.0 + I.z);
float b = -I.x * I.y * a;
vec3 b1 = vec3(1.0 - I.x * I.x * a, b, -I.x);
vec3 b2 = vec3(b, 1.0 - I.y * I.y * a, -I.y);
vec2 matcap_uv = vec2(dot(b1, N), dot(b2, N));
if (flipped) {
matcap_uv.x = -matcap_uv.x;
}
return matcap_uv * 0.496 + 0.5;
}
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