Cleanup: adjust the usage and naming of a few utility functions
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@ -88,116 +88,57 @@ ccl_device int bsdf_microfacet_hair_setup(ccl_private ShaderData *sd,
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#endif /* __HAIR__ */
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ccl_device_inline float3 make_float3_from_float(const float f)
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{
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return make_float3(f, f, f);
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}
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/* -------------------------------------------------------------------- */
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/** \name Hair coordinate system utils.
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* \{ */
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ccl_device_inline float3 reflect_vector(const float3 w, const float3 n)
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{
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return 2.f * dot(w, n) * n - w;
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}
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ccl_device float3 refract_vector(const float3 w,
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const float3 n,
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const float cos_theta_t,
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const float eta_ti)
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{
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return n * (dot(w, n) * eta_ti + cos_theta_t) - w * eta_ti;
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}
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ccl_device_inline float3 microfacet_visible_normal_sample(KernelGlobals kg,
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const bool beckmann,
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const float roughness,
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const float3 wi,
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const float randu,
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const float randv,
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ccl_private float *G1i)
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{
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/* Step 1 : stretch wi */
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float3 omega_i_ = normalize(make_float3(roughness * wi.x, roughness * wi.y, wi.z));
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/* get polar coordinates of omega_i_ */
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float costheta_ = 1.f;
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float sintheta_ = 0.f;
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float cosphi_ = 1.f;
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float sinphi_ = 0.f;
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if (omega_i_.z < 0.99999f) {
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costheta_ = omega_i_.z;
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sintheta_ = safe_sqrtf(1.f - costheta_ * costheta_);
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float invlen = 1.f / sintheta_;
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cosphi_ = omega_i_.x * invlen;
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sinphi_ = omega_i_.y * invlen;
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}
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/* 2. sample P22_{omega_i}(x_slope, y_slope, 1, 1) */
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float slope_x, slope_y;
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if (beckmann) {
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microfacet_beckmann_sample_slopes(
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kg, costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i);
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}
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else {
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microfacet_ggx_sample_slopes(costheta_, sintheta_, randu, randv, &slope_x, &slope_y, G1i);
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}
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/* 3. rotate */
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float tmp = cosphi_ * slope_x - sinphi_ * slope_y;
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slope_y = sinphi_ * slope_x + cosphi_ * slope_y;
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slope_x = tmp;
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/* 4. unstretch */
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slope_x = roughness * slope_x;
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slope_y = roughness * slope_y;
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/* 5. compute normal */
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return normalize(make_float3(-slope_x, -slope_y, 1.f));
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}
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/* returns sin_theta */
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ccl_device_inline float sintheta(const float3 w)
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/* Returns sin(theta) of the given direction. */
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ccl_device_inline float sin_theta(const float3 w)
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{
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return w.y;
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}
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/* returns cos_theta */
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ccl_device_inline float costheta(const float3 w)
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/* Returns cos(theta) of the given direction. */
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ccl_device_inline float cos_theta(const float3 w)
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{
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return safe_sqrtf(sqr(w.x) + sqr(w.z));
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}
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/* returns tan_theta */
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ccl_device_inline float tantheta(const float3 w)
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/* Returns tan(theta) of the given direction. */
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ccl_device_inline float tan_theta(const float3 w)
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{
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return sintheta(w) / costheta(w);
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return sin_theta(w) / cos_theta(w);
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}
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/* extract theta coordinate from 3D direction
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/* Returns sin(phi) and cos(phi) of the given direction. */
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ccl_device float2 sincos_phi(const float3 w)
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{
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float c = cos_theta(w);
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return make_float2(w.x / c, w.z / c);
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}
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/* Extract the theta coordinate from the given direction.
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* -pi < theta < pi */
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ccl_device_inline float dir_theta(const float3 w)
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{
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return atan2f(sintheta(w), costheta(w));
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return atan2f(sin_theta(w), cos_theta(w));
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}
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/* extract phi coordinate from 3D direction.
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* -pi < phi < pi
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* Assuming phi(wi) = 0 */
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/* Extract the phi coordinate from the given direction, assuming phi(wi) = 0.
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* -pi < phi < pi */
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ccl_device_inline float dir_phi(const float3 w)
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{
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return atan2f(w.x, w.z);
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}
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/* extract theta and phi coordinate from 3D direction
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* -pi/2 < theta < pi/2, -pi < phi < pi
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* Assuming phi(wi) = 0 */
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/* Extract theta and phi coordinates from the given direction, assuming phi(wi) = 0.
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* -pi/2 < theta < pi/2, -pi < phi < pi */
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ccl_device_inline float2 dir_sph(const float3 w)
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{
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return make_float2(dir_theta(w), dir_phi(w));
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}
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/* compute the vector direction given spherical coordinates */
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/* Compute the vector direction given spherical coordinates */
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ccl_device_inline float3 sph_dir(float theta, float gamma)
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{
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float sin_theta = sinf(theta);
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@ -207,6 +148,49 @@ ccl_device_inline float3 sph_dir(float theta, float gamma)
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return make_float3(sin_gamma * cos_theta, sin_theta, cos_gamma * cos_theta);
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}
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/* Utility functions for elliptical cross-sections. */
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/* Conversion between gamma and phi. Notations see Figure 5 in the paper. */
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ccl_device float to_phi(float gamma, float a, float b)
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{
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float sin_gamma = sinf(gamma);
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float cos_gamma = cosf(gamma);
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return atan2f(b * sin_gamma, a * cos_gamma);
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}
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ccl_device float to_gamma(float phi, float a, float b)
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{
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float sin_phi = sinf(phi);
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float cos_phi = cosf(phi);
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return atan2f(a * sin_phi, b * cos_phi);
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}
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/* Compute the coordinate on the ellipse, given gamma, the semi-major and semi-minor axes. */
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ccl_device float2 to_point(float gamma, float a, float b)
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{
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float sin_gamma = sinf(gamma);
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float cos_gamma = cosf(gamma);
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return make_float2(a * sin_gamma, b * cos_gamma);
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}
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/* Compute the vector direction given by theta and gamma. */
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ccl_device float3 sphg_dir(float theta, float gamma, float a, float b)
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{
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float sin_theta = sinf(theta);
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float cos_theta = cosf(theta);
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float sin_gamma = sinf(gamma);
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float cos_gamma = cosf(gamma);
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float tan_gamma = sin_gamma / cos_gamma;
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float tan_phi = b / a * tan_gamma;
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float cos_phi = 1.f / sqrtf(sqr(tan_phi) + 1.f);
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if (cos_gamma < 0.f)
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cos_phi = -cos_phi;
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float sin_phi = cos_phi * tan_phi;
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return make_float3(sin_phi * cos_theta, sin_theta, cos_phi * cos_theta);
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}
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/** \} */
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/* sample microfacets from a tilted mesonormal */
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ccl_device_inline float3 sample_wh(KernelGlobals kg,
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const bool beckmann,
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@ -224,8 +208,8 @@ ccl_device_inline float3 sample_wh(KernelGlobals kg,
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const float3 wi_wm = make_float3(dot(wi, s), dot(wi, t), dot(wi, n));
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float G1o;
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const float3 wh_wm = microfacet_visible_normal_sample(
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kg, beckmann, roughness, wi_wm, randu, randv, &G1o);
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const float3 wh_wm = microfacet_sample_stretched(
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kg, wi_wm, roughness, roughness, randu, randv, beckmann, &G1o);
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const float3 wh = wh_wm.x * s + wh_wm.y * t + wh_wm.z * n;
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return wh;
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@ -305,14 +289,14 @@ ccl_device float D(const bool beckmann, const float roughness, const float3 m, c
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}
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/* Fresnel */
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/* TODO: cleanup or refer to mitsuba */
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ccl_device float fresnel(float cos_theta_i,
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float eta,
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ccl_private float &cos_theta_t,
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ccl_private float &eta_it,
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ccl_private float &eta_ti)
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{
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const float rcp_eta = 1.f / eta;
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float cos_theta_i_abs;
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float cos_theta_i_abs, eta_it;
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if (cos_theta_i >= 0.f) {
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eta_it = eta;
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eta_ti = rcp_eta;
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@ -348,42 +332,6 @@ ccl_device float fresnel(float cos_theta_i,
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return r;
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}
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ccl_device float fresnel0(float cos_theta_i, float eta)
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{
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if (eta == 1.f)
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return 0.f;
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if (cos_theta_i == 0.f)
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return 1.f;
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const float rcp_eta = 1.f / eta;
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float eta_it, eta_ti, cos_theta_i_abs;
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if (cos_theta_i >= 0.f) {
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eta_it = eta;
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eta_ti = rcp_eta;
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cos_theta_i_abs = cos_theta_i;
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}
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else {
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eta_it = rcp_eta;
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eta_ti = eta;
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cos_theta_i_abs = -cos_theta_i;
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}
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/* Using Snell's law, calculate the squared sine of the angle between the surface normal and the
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* transmitted ray */
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float cos_theta_t_sqr = 1.f - eta_ti * eta_ti * (1.f - cos_theta_i * cos_theta_i);
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float cos_theta_t_abs = safe_sqrtf(cos_theta_t_sqr);
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/* Amplitudes of reflected waves */
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float a_s = (cos_theta_i_abs - eta_it * cos_theta_t_abs) /
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(cos_theta_i_abs + eta_it * cos_theta_t_abs);
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float a_p = (cos_theta_t_abs - eta_it * cos_theta_i_abs) /
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(cos_theta_t_abs + eta_it * cos_theta_i_abs);
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float r = .5f * (sqr(a_s) + sqr(a_p));
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return r;
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}
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ccl_device float3 bsdf_microfacet_hair_eval_r_circular(ccl_private const ShaderClosure *sc,
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const float3 wi,
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const float3 wo)
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@ -404,13 +352,13 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_circular(ccl_private const ShaderC
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/* dot(wi, wmi) > 0 */
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const float tan_tilt = tanf(tilt);
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float phi_m_max1 = acosf(fmaxf(-tan_tilt * tantheta(wi), 0.f));
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float phi_m_max1 = acosf(fmaxf(-tan_tilt * tan_theta(wi), 0.f));
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if (isnan_safe(phi_m_max1))
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return R;
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const float phi_m_min1 = -phi_m_max1;
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/* dot(wo, wmi) > 0 */
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const float phi_m_max2 = acosf(fmaxf(-tan_tilt * tantheta(wo), 0.f)) + phi_o;
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const float phi_m_max2 = acosf(fmaxf(-tan_tilt * tan_theta(wo), 0.f)) + phi_o;
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if (isnan_safe(phi_m_max2))
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return R;
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const float phi_m_min2 = -phi_m_max2 + 2.f * phi_o;
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@ -434,8 +382,8 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_circular(ccl_private const ShaderC
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const float cm = cosf(tilt);
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const float C = sqrtf(1.f - roughness_squared);
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const float A = cm * costheta(wh) * C;
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const float B = sm * sintheta(wh) * C;
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const float A = cm * cos_theta(wh) * C;
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const float B = sm * sin_theta(wh) * C;
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const float A2 = sqr(A);
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const float B2 = sqr(B);
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const float tmp1 = 1.f / sqrtf(sqr(B - 1.f) - A2);
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@ -488,9 +436,9 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_circular(ccl_private const ShaderC
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integral *= (2.f / 3.f * res);
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}
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const float F = fresnel0(dot(wi, wh), eta);
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const float F = fresnel_dielectric_cos(dot(wi, wh), eta);
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R = make_float3_from_float(bsdf->extra->R * 0.125f * F * fmaxf(0.f, integral));
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R = make_float3(bsdf->extra->R * 0.125f * F * fmaxf(0.f, integral));
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return R;
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}
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@ -511,13 +459,13 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
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/* dot(wi, wmi) > 0 */
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const float tan_tilt = tanf(tilt);
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float phi_m_max = acosf(fmaxf(-tan_tilt * tantheta(wi), 0.f));
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float phi_m_max = acosf(fmaxf(-tan_tilt * tan_theta(wi), 0.f));
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if (isnan_safe(phi_m_max))
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return zero_float3();
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float phi_m_min = -phi_m_max;
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/* dot(wo, wmo) < 0 */
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float tmp1 = acosf(fminf(tan_tilt * tantheta(wo), 0.f));
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float tmp1 = acosf(fminf(tan_tilt * tan_theta(wo), 0.f));
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if (isnan_safe(tmp1))
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return zero_float3();
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@ -548,11 +496,11 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
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if (dot_wi_wh1 <= 1e-5f)
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continue;
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float cos_theta_t1, eta_it1, eta_ti1;
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const float T1 = 1.f - fresnel(dot_wi_wh1, eta, cos_theta_t1, eta_it1, eta_ti1);
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float cos_theta_t1, eta_ti1;
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const float T1 = 1.f - fresnel(dot_wi_wh1, eta, cos_theta_t1, eta_ti1);
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/* refraction at the first interface */
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const float3 wt = refract_vector(wi, wh1, cos_theta_t1, eta_ti1);
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const float3 wt = -refract(wi, wh1, cos_theta_t1, eta_ti1);
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const float phi_t = dir_phi(wt);
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const float phi_mt = 2.f * phi_t - phi_mi;
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const float3 wmt = sph_dir(-tilt, phi_mt);
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@ -564,7 +512,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
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/* Simpson's rule weight */
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float weight = (i == 0 || i == intervals - 1) ? 0.5f : (i % 2 + 1);
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float3 A_t = exp(mu_a * 2.f * cosf(phi_t - phi_mi) / costheta(wt));
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float3 A_t = exp(mu_a * 2.f * cosf(phi_t - phi_mi) / cos_theta(wt));
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/* TT */
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if (bsdf->extra->TT > 0.f) {
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@ -581,7 +529,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
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float dot_wt_wh2 = dot(-wt, wh2);
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const float T2 = 1.f - fresnel0(dot_wt_wh2, inv_eta);
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const float T2 = 1.f - fresnel_dielectric_cos(dot_wt_wh2, inv_eta);
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float D2 = D(beckmann, roughness, wh2, wmt) * G(beckmann, roughness, -wt, -wo, wmt, wh2);
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const float3 result = T1 * T2 * D2 * A_t * dot_wt_wh2 * dot(wo, wh2) *
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@ -607,8 +555,8 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
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if (cos_th2 <= 1e-5f)
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continue;
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const float R2 = fresnel0(cos_th2, inv_eta);
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float3 wtr = reflect_vector(wt, wh2);
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const float R2 = fresnel_dielectric_cos(cos_th2, inv_eta);
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float3 wtr = -reflect(wt, wh2);
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float G2 = G(beckmann, roughness, -wt, -wtr, wmt, wh2);
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if (G2 == 0.f || G_(-wt, -wtr, make_float3(wmt.x, 0.f, wmt.z), wh2) == 0.f)
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@ -632,10 +580,10 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_circular(KernelGlobals kg,
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wh3 *= rcp_norm_wh3;
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const float cos_trh3 = dot(wh3, wtr);
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const float T3 = 1.f - fresnel0(cos_trh3, inv_eta);
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const float T3 = 1.f - fresnel_dielectric_cos(cos_trh3, inv_eta);
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const float D3 = D(beckmann, roughness, wh3, wmtr) * G3;
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const float3 A_tr = exp(mu_a * 2.f * cosf(phi_tr - phi_mt) / costheta(wtr));
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const float3 A_tr = exp(mu_a * 2.f * cosf(phi_tr - phi_mt) / cos_theta(wtr));
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const float3 result = T1 * R2 * T3 * D3 * cos_trh3 * dot(wh3, wo) * sqr(rcp_norm_wh3) * A_t *
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A_tr * weight / (dot(wt, wmi) * dot(wtr, wmt)) *
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@ -678,12 +626,12 @@ ccl_device Spectrum bsdf_microfacet_hair_eval_circular(KernelGlobals kg,
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*pdf = 1.f;
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// original from Huang's EGSR 2022
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// return rgb_to_spectrum(R / costheta(wi));
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// return rgb_to_spectrum(R / cos_theta(wi));
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// correction: the extra costheta(wo) corresponds to the lack of consideration of Zinke's
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// correction: the extra cos_theta(wo) corresponds to the lack of consideration of Zinke's
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// cos_theta_i^2 in the BCSDF; for instance eq[2] in Huang's should include an extra cos_theta_i
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// (plus here remember wi and wo meanings are flipped)
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return rgb_to_spectrum(R / (costheta(wi) * costheta(wo)));
|
||||
return rgb_to_spectrum(R / (cos_theta(wi) * cos_theta(wo)));
|
||||
}
|
||||
|
||||
ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
||||
|
|
@ -750,7 +698,7 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
|
||||
/* sample R lobe */
|
||||
const float3 wh1 = sample_wh(kg, beckmann, roughness, wi, wmi, sample_h1.x, sample_h1.y);
|
||||
const float3 wr = reflect_vector(wi, wh1);
|
||||
const float3 wr = -reflect(wi, wh1);
|
||||
|
||||
/* ensure that this is a valid sample */
|
||||
if (dot(wr, wh1) <= 0.f || dot(wr, wmi) <= 0.f || !G_(wi, wr, wmi_, wh1)) {
|
||||
|
|
@ -761,12 +709,12 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
float3 TT = zero_float3();
|
||||
float3 TRT = zero_float3();
|
||||
|
||||
float cos_theta_t1, eta_it1, eta_ti1;
|
||||
float R1 = fresnel(dot(wi, wh1), *eta, cos_theta_t1, eta_it1, eta_ti1);
|
||||
float3 R = make_float3_from_float(bsdf->extra->R * R1);
|
||||
float cos_theta_t1, eta_ti1;
|
||||
float R1 = fresnel(dot(wi, wh1), *eta, cos_theta_t1, eta_ti1);
|
||||
float3 R = make_float3(bsdf->extra->R * R1);
|
||||
|
||||
/* sample TT lobe */
|
||||
const float3 wt = refract_vector(wi, wh1, cos_theta_t1, eta_ti1);
|
||||
const float3 wt = -refract(wi, wh1, cos_theta_t1, eta_ti1);
|
||||
const float phi_t = dir_phi(wt);
|
||||
|
||||
float phi_mi = atan2f(sin_phi_mi, cos_phi_mi);
|
||||
|
|
@ -776,7 +724,7 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
const float3 wmt_ = sph_dir(0.f, phi_mt);
|
||||
|
||||
const float3 wh2 = sample_wh(kg, beckmann, roughness, -wt, wmt, sample_h2.x, sample_h2.y);
|
||||
const float3 wtr = reflect_vector(wt, wh2);
|
||||
const float3 wtr = -reflect(wt, wh2);
|
||||
|
||||
float3 wh3;
|
||||
float3 wtt, wtrt;
|
||||
|
|
@ -791,12 +739,12 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
const float3 A_t = exp(-mu_a * (2.f * cos_gamma_t / cos_theta_wt));
|
||||
|
||||
const float inv_eta = 1.f / *eta;
|
||||
float cos_theta_t2, eta_it2, eta_ti2;
|
||||
const float R2 = fresnel(dot(-wt, wh2), inv_eta, cos_theta_t2, eta_it2, eta_ti2);
|
||||
const float3 T1 = make_float3_from_float(1.f - R1);
|
||||
const float3 T2 = make_float3_from_float(1.f - R2);
|
||||
float cos_theta_t2, eta_ti2;
|
||||
const float R2 = fresnel(dot(-wt, wh2), inv_eta, cos_theta_t2, eta_ti2);
|
||||
const float3 T1 = make_float3(1.f - R1);
|
||||
const float3 T2 = make_float3(1.f - R2);
|
||||
|
||||
wtt = refract_vector(-wt, wh2, cos_theta_t2, eta_ti2);
|
||||
wtt = -refract(-wt, wh2, cos_theta_t2, eta_ti2);
|
||||
|
||||
if (dot(wtt, wmt) < 0.f && cos_theta_t2 != 0.f) /* total internal reflection */
|
||||
TT = bsdf->extra->TT * T1 * A_t * T2;
|
||||
|
|
@ -809,15 +757,15 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
|
||||
wh3 = sample_wh(kg, beckmann, roughness, wtr, wmtr, sample_h3.x, sample_h3.y);
|
||||
|
||||
float cos_theta_t3, eta_it3, eta_ti3;
|
||||
const float R3 = fresnel(dot(wtr, wh3), inv_eta, cos_theta_t3, eta_it3, eta_ti3);
|
||||
float cos_theta_t3, eta_ti3;
|
||||
const float R3 = fresnel(dot(wtr, wh3), inv_eta, cos_theta_t3, eta_ti3);
|
||||
|
||||
wtrt = refract_vector(wtr, wh3, cos_theta_t3, eta_ti3);
|
||||
wtrt = -refract(wtr, wh3, cos_theta_t3, eta_ti3);
|
||||
|
||||
if (cos_theta_t3 != 0.f && dot(wtr, wh3) > 0.f && dot(wmtr, wtr) > 0.f &&
|
||||
dot(wtrt, wmtr) < 0.f && G_(wtr, -wtrt, make_float3(wmtr.x, 0.f, wmtr.z), wh3)) {
|
||||
|
||||
const float3 T3 = make_float3_from_float(1.f - R3);
|
||||
const float3 T3 = make_float3(1.f - R3);
|
||||
const float cos_gamma_t2 = -cos(phi_tr - phi_mt);
|
||||
const float cos_theta_wtr = sqrtf(1.f - sqr(wtr.y));
|
||||
const float3 A_tr = exp(-mu_a * (2.f * cos_gamma_t2 / cos_theta_wtr));
|
||||
|
|
@ -876,10 +824,10 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
// original from Huang's EGSR 2022
|
||||
//*eval *= visibility;
|
||||
|
||||
// correction: the extra costheta(wo) corresponds to the lack of consideration of Zinke's
|
||||
// correction: the extra cos_theta(wo) corresponds to the lack of consideration of Zinke's
|
||||
// cos_theta_i^2 in the BCSDF; for instance eq[2] in Huang's should include an extra cos_theta_i
|
||||
// (plus here remember wi and wo meanings are flipped)
|
||||
*eval *= visibility / costheta(wo);
|
||||
*eval *= visibility / cos_theta(wo);
|
||||
|
||||
*omega_in = wo.x * X + wo.y * Y + wo.z * Z;
|
||||
|
||||
|
|
@ -895,60 +843,6 @@ ccl_device int bsdf_microfacet_hair_sample_circular(const KernelGlobals kg,
|
|||
|
||||
/* Elliptic specific */
|
||||
|
||||
ccl_device float sinphi(const float3 w)
|
||||
{
|
||||
return w.x / costheta(w);
|
||||
}
|
||||
|
||||
ccl_device float cosphi(const float3 w)
|
||||
{
|
||||
return w.z / costheta(w);
|
||||
}
|
||||
|
||||
ccl_device float2 sincosphi(const float3 w)
|
||||
{
|
||||
float cos_theta = costheta(w);
|
||||
return make_float2(w.x / cos_theta, w.z / cos_theta);
|
||||
}
|
||||
|
||||
/* convert between gamma and phi */
|
||||
ccl_device float to_phi(float gamma, float a, float b)
|
||||
{
|
||||
float sin_gamma = sinf(gamma);
|
||||
float cos_gamma = cosf(gamma);
|
||||
return atan2f(b * sin_gamma, a * cos_gamma);
|
||||
}
|
||||
|
||||
ccl_device float to_gamma(float phi, float a, float b)
|
||||
{
|
||||
float sin_phi = sinf(phi);
|
||||
float cos_phi = cosf(phi);
|
||||
return atan2f(a * sin_phi, b * cos_phi);
|
||||
}
|
||||
|
||||
ccl_device float2 to_point(float gamma, float a, float b)
|
||||
{
|
||||
float sin_gamma = sinf(gamma);
|
||||
float cos_gamma = cosf(gamma);
|
||||
return make_float2(a * sin_gamma, b * cos_gamma);
|
||||
}
|
||||
|
||||
/* given theta and gamma, convert to vector */
|
||||
ccl_device float3 sphg_dir(float theta, float gamma, float a, float b)
|
||||
{
|
||||
float sin_theta = sinf(theta);
|
||||
float cos_theta = cosf(theta);
|
||||
float sin_gamma = sinf(gamma);
|
||||
float cos_gamma = cosf(gamma);
|
||||
float tan_gamma = sin_gamma / cos_gamma;
|
||||
float tan_phi = b / a * tan_gamma;
|
||||
float cos_phi = 1.f / sqrtf(sqr(tan_phi) + 1.f);
|
||||
if (cos_gamma < 0.f)
|
||||
cos_phi = -cos_phi;
|
||||
float sin_phi = cos_phi * tan_phi;
|
||||
return make_float3(sin_phi * cos_theta, sin_theta, cos_phi * cos_theta);
|
||||
}
|
||||
|
||||
ccl_device float3 bsdf_microfacet_hair_eval_r_elliptic(ccl_private const ShaderClosure *sc,
|
||||
const float3 wi_,
|
||||
const float3 wo_)
|
||||
|
|
@ -978,13 +872,13 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_elliptic(ccl_private const ShaderC
|
|||
|
||||
/* dot(wi, wmi) > 0 */
|
||||
const float tan_tilt = tanf(tilt);
|
||||
float phi_m_max1 = acosf(fmaxf(-tan_tilt * tantheta(wi), 0.f)) + phi_i;
|
||||
float phi_m_max1 = acosf(fmaxf(-tan_tilt * tan_theta(wi), 0.f)) + phi_i;
|
||||
if (isnan_safe(phi_m_max1))
|
||||
return R;
|
||||
float phi_m_min1 = -phi_m_max1 + 2.f * phi_i;
|
||||
|
||||
/* dot(wo, wmi) > 0 */
|
||||
float phi_m_max2 = acosf(fmaxf(-tan_tilt * tantheta(wo), 0.f)) + phi_o;
|
||||
float phi_m_max2 = acosf(fmaxf(-tan_tilt * tan_theta(wo), 0.f)) + phi_o;
|
||||
if (isnan_safe(phi_m_max2))
|
||||
return R;
|
||||
float phi_m_min2 = -phi_m_max2 + 2.f * phi_o;
|
||||
|
|
@ -1038,10 +932,10 @@ ccl_device float3 bsdf_microfacet_hair_eval_r_elliptic(ccl_private const ShaderC
|
|||
|
||||
integral *= (2.f / 3.f * res);
|
||||
|
||||
const float F = fresnel0(dot(wi, wh), eta);
|
||||
const float F = fresnel_dielectric_cos(dot(wi, wh), eta);
|
||||
const float d_o_inv = 1.f / sqrtf(1.f - e2 * sqr(sinf(phi_o)));
|
||||
|
||||
R = make_float3_from_float(bsdf->extra->R * 0.125f * F * integral * d_o_inv);
|
||||
R = make_float3(bsdf->extra->R * 0.125f * F * integral * d_o_inv);
|
||||
return R;
|
||||
}
|
||||
|
||||
|
|
@ -1069,13 +963,13 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
|
|||
|
||||
/* dot(wi, wmi) > 0 */
|
||||
const float tan_tilt = tanf(tilt);
|
||||
float phi_m_max = acosf(fmaxf(-tan_tilt * tantheta(wi), 0.f)) + phi_i;
|
||||
float phi_m_max = acosf(fmaxf(-tan_tilt * tan_theta(wi), 0.f)) + phi_i;
|
||||
if (isnan_safe(phi_m_max))
|
||||
return zero_float3();
|
||||
float phi_m_min = -phi_m_max + 2.f * phi_i;
|
||||
|
||||
/* dot(wo, wmo) < 0 */
|
||||
float tmp1 = acosf(fminf(tan_tilt * tantheta(wo), 0.f));
|
||||
float tmp1 = acosf(fminf(tan_tilt * tan_theta(wo), 0.f));
|
||||
if (isnan_safe(tmp1))
|
||||
return zero_float3();
|
||||
|
||||
|
|
@ -1118,11 +1012,11 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
|
|||
if (dot_wi_wh1 <= 1e-5f)
|
||||
continue;
|
||||
|
||||
float cos_theta_t1, eta_it1, eta_ti1;
|
||||
const float T1 = 1.f - fresnel(dot_wi_wh1, eta, cos_theta_t1, eta_it1, eta_ti1);
|
||||
float cos_theta_t1, eta_ti1;
|
||||
const float T1 = 1.f - fresnel(dot_wi_wh1, eta, cos_theta_t1, eta_ti1);
|
||||
|
||||
/* refraction at the first interface */
|
||||
const float3 wt = refract_vector(wi, wh1, cos_theta_t1, eta_ti1);
|
||||
const float3 wt = -refract(wi, wh1, cos_theta_t1, eta_ti1);
|
||||
const float phi_t = dir_phi(wt);
|
||||
const float gamma_mt = 2.f * to_phi(phi_t, a, b) - gamma_mi;
|
||||
const float3 wmt = sphg_dir(-tilt, gamma_mt, a, b);
|
||||
|
|
@ -1137,7 +1031,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
|
|||
|
||||
const float2 pi = to_point(gamma_mi, a, b);
|
||||
const float2 pt = to_point(gamma_mt + M_PI_F, a, b);
|
||||
const float3 A_t = exp(-mu_a * len(pi - pt) / costheta(wt));
|
||||
const float3 A_t = exp(-mu_a * len(pi - pt) / cos_theta(wt));
|
||||
|
||||
/* TT */
|
||||
if (bsdf->extra->TT > 0.f) {
|
||||
|
|
@ -1154,7 +1048,7 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
|
|||
|
||||
const float dot_wt_wh2 = dot(-wt, wh2);
|
||||
|
||||
const float T2 = 1.f - fresnel0(dot_wt_wh2, inv_eta);
|
||||
const float T2 = 1.f - fresnel_dielectric_cos(dot_wt_wh2, inv_eta);
|
||||
const float D2 = D(beckmann, roughness, wh2, wmt) *
|
||||
G(beckmann, roughness, -wt, -wo, wmt, wh2);
|
||||
|
||||
|
|
@ -1183,8 +1077,8 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
|
|||
if (cos_th2 <= 1e-5f)
|
||||
continue;
|
||||
|
||||
const float R2 = fresnel0(cos_th2, inv_eta);
|
||||
const float3 wtr = reflect_vector(wt, wh2);
|
||||
const float R2 = fresnel_dielectric_cos(cos_th2, inv_eta);
|
||||
const float3 wtr = -reflect(wt, wh2);
|
||||
|
||||
const float G2 = G(beckmann, roughness, -wt, -wtr, wmt, wh2);
|
||||
if (G2 == 0.f || !G_(-wt, -wtr, wmt_, wh2))
|
||||
|
|
@ -1210,12 +1104,12 @@ ccl_device float3 bsdf_microfacet_hair_eval_tt_trt_elliptic(KernelGlobals kg,
|
|||
|
||||
const float cos_trh3 = dot(wh3, wtr);
|
||||
|
||||
const float T3 = 1.f - fresnel0(cos_trh3, inv_eta);
|
||||
const float T3 = 1.f - fresnel_dielectric_cos(cos_trh3, inv_eta);
|
||||
|
||||
const float D3 = D(beckmann, roughness, wh3, wmtr) * G3;
|
||||
|
||||
const float2 ptr = to_point(gamma_mtr + M_PI_F, a, b);
|
||||
const float3 A_tr = exp(-mu_a * len(pt - ptr) / costheta(wtr));
|
||||
const float3 A_tr = exp(-mu_a * len(pt - ptr) / cos_theta(wtr));
|
||||
|
||||
const float3 result = T1 * R2 * T3 * D3 * cos_trh3 * dot(wh3, wo) * sqr(rcp_norm_wh3) * A_t *
|
||||
A_tr * weight / (dot(wt, wmi) * dot(wtr, wmt)) *
|
||||
|
|
@ -1269,9 +1163,9 @@ ccl_device Spectrum bsdf_microfacet_hair_eval_elliptic(KernelGlobals kg,
|
|||
|
||||
*pdf = 1.f;
|
||||
|
||||
// return rgb_to_spectrum(R / costheta(wi)); // original from Huang's EGSR 2022
|
||||
return rgb_to_spectrum(R / (costheta(wi) * costheta(wo)));
|
||||
// correction: the extra costheta(wo) corresponds to the lack of consideration of Zinke's
|
||||
// return rgb_to_spectrum(R / cos_theta(wi)); // original from Huang's EGSR 2022
|
||||
return rgb_to_spectrum(R / (cos_theta(wi) * cos_theta(wo)));
|
||||
// correction: the extra cos_theta(wo) corresponds to the lack of consideration of Zinke's
|
||||
// cos_theta_i^2 in the BCSDF; for instance eq[2] in Huang's should include an extra cos_theta_i
|
||||
// (plus here remember wi and wo meanings are flipped)
|
||||
}
|
||||
|
|
@ -1338,9 +1232,9 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
|
|||
const float e2 = 1.f - sqr(b / a);
|
||||
|
||||
/* macronormal */
|
||||
const float2 sin_cos_phi_i = sincosphi(wi);
|
||||
const float sin_phi_i = sin_cos_phi_i.x;
|
||||
const float cos_phi_i = sin_cos_phi_i.y;
|
||||
const float2 sincos_phi_i = sincos_phi(wi);
|
||||
const float sin_phi_i = sincos_phi_i.x;
|
||||
const float cos_phi_i = sincos_phi_i.y;
|
||||
const float d_i = sqrtf(1.f - e2 * sqr(sin_phi_i));
|
||||
const float h = d_i * (sample_h * 2.f - 1.f);
|
||||
const float gamma_mi = atan2f(cos_phi_i, -b / a * sin_phi_i) -
|
||||
|
|
@ -1363,7 +1257,7 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
|
|||
/* sample R lobe */
|
||||
const float3 wh1 = sample_wh(kg, beckmann, roughness, wi, wmi, sample_h1.x, sample_h1.y);
|
||||
|
||||
const float3 wr = reflect_vector(wi, wh1);
|
||||
const float3 wr = -reflect(wi, wh1);
|
||||
|
||||
/* ensure that this is a valid sample */
|
||||
if (dot(wr, wh1) <= 0.f || dot(wr, wmi) <= 0.f || !G_(wi, wr, wmi_, wh1)) {
|
||||
|
|
@ -1374,12 +1268,12 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
|
|||
float3 TT = zero_float3();
|
||||
float3 TRT = zero_float3();
|
||||
|
||||
float cos_theta_t1, eta_it1, eta_ti1;
|
||||
const float R1 = fresnel(dot(wi, wh1), *eta, cos_theta_t1, eta_it1, eta_ti1);
|
||||
float3 R = make_float3_from_float(bsdf->extra->R * R1);
|
||||
float cos_theta_t1, eta_ti1;
|
||||
const float R1 = fresnel(dot(wi, wh1), *eta, cos_theta_t1, eta_ti1);
|
||||
float3 R = make_float3(bsdf->extra->R * R1);
|
||||
|
||||
/* sample TT lobe */
|
||||
const float3 wt = refract_vector(wi, wh1, cos_theta_t1, eta_ti1);
|
||||
const float3 wt = -refract(wi, wh1, cos_theta_t1, eta_ti1);
|
||||
const float phi_t = dir_phi(wt);
|
||||
|
||||
const float gamma_mt = 2.f * to_phi(phi_t, a, b) - gamma_mi;
|
||||
|
|
@ -1388,7 +1282,7 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
|
|||
|
||||
const float3 wh2 = sample_wh(kg, beckmann, roughness, -wt, wmt, sample_h2.x, sample_h2.y);
|
||||
|
||||
const float3 wtr = reflect_vector(wt, wh2);
|
||||
const float3 wtr = -reflect(wt, wh2);
|
||||
|
||||
float3 wh3;
|
||||
float3 wtt, wtrt;
|
||||
|
|
@ -1400,15 +1294,15 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
|
|||
const float3 mu_a = bsdf->sigma;
|
||||
const float2 pi = to_point(gamma_mi, a, b);
|
||||
const float2 pt = to_point(gamma_mt + M_PI_F, a, b);
|
||||
const float3 A_t = exp(-mu_a * len(pi - pt) / costheta(wt));
|
||||
const float3 A_t = exp(-mu_a * len(pi - pt) / cos_theta(wt));
|
||||
|
||||
const float inv_eta = 1.f / *eta;
|
||||
float cos_theta_t2, eta_it2, eta_ti2;
|
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const float R2 = fresnel(dot(-wt, wh2), inv_eta, cos_theta_t2, eta_it2, eta_ti2);
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const float3 T1 = make_float3_from_float(1.f - R1);
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const float3 T2 = make_float3_from_float(1.f - R2);
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float cos_theta_t2, eta_ti2;
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const float R2 = fresnel(dot(-wt, wh2), inv_eta, cos_theta_t2, eta_ti2);
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const float3 T1 = make_float3(1.f - R1);
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const float3 T2 = make_float3(1.f - R2);
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wtt = refract_vector(-wt, wh2, cos_theta_t2, eta_ti2);
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wtt = -refract(-wt, wh2, cos_theta_t2, eta_ti2);
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if (dot(wtt, wmt) < 0.f && cos_theta_t2 != 0.f) /* total internal reflection */
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TT = bsdf->extra->TT * T1 * A_t * T2;
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@ -1421,18 +1315,18 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
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||||
wh3 = sample_wh(kg, beckmann, roughness, wtr, wmtr, sample_h3.x, sample_h3.y);
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||||
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||||
float cos_theta_t3, eta_it3, eta_ti3;
|
||||
const float R3 = fresnel(dot(wtr, wh3), inv_eta, cos_theta_t3, eta_it3, eta_ti3);
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||||
float cos_theta_t3, eta_ti3;
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||||
const float R3 = fresnel(dot(wtr, wh3), inv_eta, cos_theta_t3, eta_ti3);
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||||
|
||||
wtrt = refract_vector(wtr, wh3, cos_theta_t3, eta_ti3);
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||||
wtrt = -refract(wtr, wh3, cos_theta_t3, eta_ti3);
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||||
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if (cos_theta_t3 != 0.f && dot(wtr, wh3) > 0.f && dot(wmtr, wtr) > 0.f &&
|
||||
dot(wtrt, wmtr) < 0.f && G_(wtr, -wtrt, make_float3(wmtr.x, 0.f, wmtr.z), wh3)) {
|
||||
|
||||
const float3 T3 = make_float3_from_float(1.f - R3);
|
||||
const float3 T3 = make_float3(1.f - R3);
|
||||
|
||||
const float2 ptr = to_point(gamma_mtr + M_PI_F, a, b);
|
||||
const float3 A_tr = exp(-mu_a * len(pt - ptr) / costheta(wtr));
|
||||
const float3 A_tr = exp(-mu_a * len(pt - ptr) / cos_theta(wtr));
|
||||
|
||||
TRT = bsdf->extra->TRT * T1 * R2 * T3 * A_t * A_tr;
|
||||
}
|
||||
|
|
@ -1486,8 +1380,8 @@ ccl_device int bsdf_microfacet_hair_sample_elliptic(const KernelGlobals kg,
|
|||
}
|
||||
|
||||
//*eval *= visibility; // original from Huang's EGSR 2022
|
||||
*eval *= visibility / costheta(wo);
|
||||
// correction: the extra costheta(wo) corresponds to the lack of consideration of Zinke's
|
||||
*eval *= visibility / cos_theta(wo);
|
||||
// correction: the extra cos_theta(wo) corresponds to the lack of consideration of Zinke's
|
||||
// cos_theta_i^2 in the BCSDF; for instance eq[2] in Huang's should include an extra cos_theta_i
|
||||
// (plus here remember wi and wo meanings are flipped)
|
||||
*omega_in = wo.x * X + wo.y * Y + wo.z * Z;
|
||||
|
|
|
|||
|
|
@ -370,6 +370,14 @@ ccl_device_inline float3 reflect(const float3 incident, const float3 normal)
|
|||
return incident - 2.0f * unit_normal * dot(incident, unit_normal);
|
||||
}
|
||||
|
||||
ccl_device_inline float3 refract(const float3 incident,
|
||||
const float3 normal,
|
||||
const float cos_theta_t,
|
||||
const float eta)
|
||||
{
|
||||
return eta * incident - (eta * dot(normal, incident) + cos_theta_t) * normal;
|
||||
}
|
||||
|
||||
ccl_device_inline float3 refract(const float3 incident, const float3 normal, const float eta)
|
||||
{
|
||||
float k = 1.0f - eta * eta * (1.0f - dot(normal, incident) * dot(normal, incident));
|
||||
|
|
|
|||
Loading…
Reference in New Issue