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path: root/intern/cycles/kernel/closure/bsdf_microfacet.h
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Diffstat (limited to 'intern/cycles/kernel/closure/bsdf_microfacet.h')
-rw-r--r--intern/cycles/kernel/closure/bsdf_microfacet.h147
1 files changed, 138 insertions, 9 deletions
diff --git a/intern/cycles/kernel/closure/bsdf_microfacet.h b/intern/cycles/kernel/closure/bsdf_microfacet.h
index 1c7b3eb9ddd..58f6140970d 100644
--- a/intern/cycles/kernel/closure/bsdf_microfacet.h
+++ b/intern/cycles/kernel/closure/bsdf_microfacet.h
@@ -36,7 +36,8 @@
CCL_NAMESPACE_BEGIN
typedef ccl_addr_space struct MicrofacetExtra {
- float3 color;
+ float3 color, cspec0;
+ float clearcoat;
} MicrofacetExtra;
typedef ccl_addr_space struct MicrofacetBsdf {
@@ -233,6 +234,36 @@ ccl_device_forceinline float3 microfacet_sample_stretched(
return normalize(make_float3(-slope_x, -slope_y, 1.0f));
}
+/* Calculate the reflection color
+ *
+ * If fresnel is used, the color is an interpolation of the F0 color and white
+ * with respect to the fresnel
+ *
+ * Else it is simply white
+ */
+ccl_device_forceinline float3 reflection_color(const MicrofacetBsdf *bsdf, float3 L, float3 H) {
+ float3 F = make_float3(1.0f, 1.0f, 1.0f);
+ bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID
+ || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID
+ || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID);
+
+ if(use_fresnel) {
+ float F0 = fresnel_dielectric_cos(1.0f, bsdf->ior);
+
+ F = interpolate_fresnel_color(L, H, bsdf->ior, F0, bsdf->extra->cspec0);
+ }
+
+ return F;
+}
+
+ccl_device_forceinline float D_GTR1(float NdotH, float alpha)
+{
+ if (alpha >= 1.0f) return M_1_PI_F;
+ float alpha2 = alpha*alpha;
+ float t = 1.0f + (alpha2 - 1.0f) * NdotH*NdotH;
+ return (alpha2 - 1.0f) / (M_PI_F * logf(alpha2) * t);
+}
+
/* GGX microfacet with Smith shadow-masking from:
*
* Microfacet Models for Refraction through Rough Surfaces
@@ -248,14 +279,44 @@ ccl_device_forceinline float3 microfacet_sample_stretched(
ccl_device int bsdf_microfacet_ggx_setup(MicrofacetBsdf *bsdf)
{
+ bsdf->extra = NULL;
+
bsdf->alpha_x = saturate(bsdf->alpha_x);
bsdf->alpha_y = bsdf->alpha_x;
-
+
bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ID;
return SD_BSDF|SD_BSDF_HAS_EVAL;
}
+ccl_device int bsdf_microfacet_ggx_fresnel_setup(MicrofacetBsdf *bsdf)
+{
+ bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x);
+ bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y);
+ bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z);
+
+ bsdf->alpha_x = saturate(bsdf->alpha_x);
+ bsdf->alpha_y = bsdf->alpha_x;
+
+ bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID;
+
+ return SD_BSDF|SD_BSDF_HAS_EVAL;
+}
+
+ccl_device int bsdf_microfacet_ggx_clearcoat_setup(MicrofacetBsdf *bsdf)
+{
+ bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x);
+ bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y);
+ bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z);
+
+ bsdf->alpha_x = saturate(bsdf->alpha_x);
+ bsdf->alpha_y = bsdf->alpha_x;
+
+ bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID;
+
+ return SD_BSDF|SD_BSDF_HAS_EVAL;
+}
+
ccl_device bool bsdf_microfacet_merge(const ShaderClosure *a, const ShaderClosure *b)
{
const MicrofacetBsdf *bsdf_a = (const MicrofacetBsdf*)a;
@@ -273,16 +334,34 @@ ccl_device bool bsdf_microfacet_merge(const ShaderClosure *a, const ShaderClosur
ccl_device int bsdf_microfacet_ggx_aniso_setup(MicrofacetBsdf *bsdf)
{
+ bsdf->extra = NULL;
+
bsdf->alpha_x = saturate(bsdf->alpha_x);
bsdf->alpha_y = saturate(bsdf->alpha_y);
-
+
bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_ID;
return SD_BSDF|SD_BSDF_HAS_EVAL;
}
+ccl_device int bsdf_microfacet_ggx_aniso_fresnel_setup(MicrofacetBsdf *bsdf)
+{
+ bsdf->extra->cspec0.x = saturate(bsdf->extra->cspec0.x);
+ bsdf->extra->cspec0.y = saturate(bsdf->extra->cspec0.y);
+ bsdf->extra->cspec0.z = saturate(bsdf->extra->cspec0.z);
+
+ bsdf->alpha_x = saturate(bsdf->alpha_x);
+ bsdf->alpha_y = saturate(bsdf->alpha_y);
+
+ bsdf->type = CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID;
+
+ return SD_BSDF|SD_BSDF_HAS_EVAL;
+}
+
ccl_device int bsdf_microfacet_ggx_refraction_setup(MicrofacetBsdf *bsdf)
{
+ bsdf->extra = NULL;
+
bsdf->alpha_x = saturate(bsdf->alpha_x);
bsdf->alpha_y = bsdf->alpha_x;
@@ -319,6 +398,8 @@ ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, cons
float alpha2 = alpha_x * alpha_y;
float D, G1o, G1i;
+ bool is_principled_clearcoat = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID);
+
if(alpha_x == alpha_y) {
/* isotropic
* eq. 20: (F*G*D)/(4*in*on)
@@ -327,7 +408,18 @@ ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, cons
float cosThetaM2 = cosThetaM * cosThetaM;
float cosThetaM4 = cosThetaM2 * cosThetaM2;
float tanThetaM2 = (1 - cosThetaM2) / cosThetaM2;
- D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
+
+ if(is_principled_clearcoat) {
+ /* use GTR1 for clearcoat */
+ D = D_GTR1(cosThetaM, bsdf->alpha_x);
+
+ /* the alpha value for clearcoat is a fixed 0.25 => alpha2 = 0.25 * 0.25 */
+ alpha2 = 0.0625f;
+ }
+ else {
+ /* use GTR2 otherwise */
+ D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
+ }
/* eq. 34: now calculate G1(i,m) and G1(o,m) */
G1o = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
@@ -374,7 +466,13 @@ ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, cons
/* eq. 20 */
float common = D * 0.25f / cosNO;
- float out = G * common;
+
+ float3 F = reflection_color(bsdf, omega_in, m);
+ if(is_principled_clearcoat) {
+ F *= 0.25f * bsdf->extra->clearcoat;
+ }
+
+ float3 out = F * G * common;
/* eq. 2 in distribution of visible normals sampling
* pm = Dw = G1o * dot(m, I) * D / dot(N, I); */
@@ -384,7 +482,7 @@ ccl_device float3 bsdf_microfacet_ggx_eval_reflect(const ShaderClosure *sc, cons
* pdf = pm * 0.25 / dot(m, I); */
*pdf = G1o * common;
- return make_float3(out, out, out);
+ return out;
}
return make_float3(0.0f, 0.0f, 0.0f);
@@ -489,6 +587,17 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
/* some high number for MIS */
*pdf = 1e6f;
*eval = make_float3(1e6f, 1e6f, 1e6f);
+
+ bool use_fresnel = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_FRESNEL_ID
+ || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID
+ || bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_ANISO_FRESNEL_ID);
+
+ /* if fresnel is used, calculate the color with reflection_color(...) */
+ if(use_fresnel) {
+ *pdf = 1.0f;
+ *eval = reflection_color(bsdf, *omega_in, m);
+ }
+
label = LABEL_REFLECT | LABEL_SINGULAR;
}
else {
@@ -497,16 +606,32 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
float alpha2 = alpha_x * alpha_y;
float D, G1i;
+ bool is_principled_clearcoat = (bsdf->type == CLOSURE_BSDF_MICROFACET_GGX_CLEARCOAT_ID);
+
if(alpha_x == alpha_y) {
/* isotropic */
float cosThetaM2 = cosThetaM * cosThetaM;
float cosThetaM4 = cosThetaM2 * cosThetaM2;
float tanThetaM2 = 1/(cosThetaM2) - 1;
- D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
/* eval BRDF*cosNI */
float cosNI = dot(N, *omega_in);
+ if(is_principled_clearcoat) {
+ /* use GTR1 for clearcoat */
+ D = D_GTR1(cosThetaM, bsdf->alpha_x);
+
+ /* the alpha value for clearcoat is a fixed 0.25 => alpha2 = 0.25 * 0.25 */
+ alpha2 = 0.0625f;
+
+ /* recalculate G1o */
+ G1o = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNO * cosNO) / (cosNO * cosNO)));
+ }
+ else {
+ /* use GTR2 otherwise */
+ D = alpha2 / (M_PI_F * cosThetaM4 * (alpha2 + tanThetaM2) * (alpha2 + tanThetaM2));
+ }
+
/* eq. 34: now calculate G1(i,m) */
G1i = 2 / (1 + safe_sqrtf(1 + alpha2 * (1 - cosNI * cosNI) / (cosNI * cosNI)));
}
@@ -538,10 +663,14 @@ ccl_device int bsdf_microfacet_ggx_sample(KernelGlobals *kg, const ShaderClosure
/* see eval function for derivation */
float common = (G1o * D) * 0.25f / cosNO;
- float out = G1i * common;
*pdf = common;
- *eval = make_float3(out, out, out);
+ float3 F = reflection_color(bsdf, *omega_in, m);
+ if(is_principled_clearcoat) {
+ F *= 0.25f * bsdf->extra->clearcoat;
+ }
+
+ *eval = G1i * common * F;
}
#ifdef __RAY_DIFFERENTIALS__
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-02 05:44:31 +0300