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Cycles: Subsurface Scattering

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New features:

* Bump mapping now works with SSS
* Texture Blur factor for SSS, see the documentation for details:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/Shaders#Subsurface_Scattering

Work in progress for feedback:

Initial implementation of the "BSSRDF Importance Sampling" paper, which uses
a different importance sampling method. It gives better quality results in
many ways, with the availability of both Cubic and Gaussian falloff functions,
but also tends to be more noisy when using the progressive integrator and does
not give great results with some geometry. It works quite well for the
non-progressive integrator and is often less noisy there.

This code may still change a lot, so unless you're testing it may be best to
stick to the Compatible falloff function.

Skin test render and file that takes advantage of the gaussian falloff:
http://www.pasteall.org/pic/show.php?id=57661
http://www.pasteall.org/pic/show.php?id=57662
http://www.pasteall.org/blend/23501
This commit is contained in:
Brecht Van Lommel
2013-08-18 14:15:57 +00:00
parent a2541508ac
commit d43682d51b
36 changed files with 1386 additions and 431 deletions
Download Patch File Download Diff File Expand all files Collapse all files

117
intern/cycles/kernel/kernel_shader.h
View File

@@ -184,52 +184,32 @@ __device_inline void shader_setup_from_subsurface(KernelGlobals *kg, ShaderData
sd->flag = kernel_tex_fetch(__object_flag, sd->object);
sd->prim = kernel_tex_fetch(__prim_index, isect->prim);
#ifdef __HAIR__
if(kernel_tex_fetch(__prim_segment, isect->prim) != ~0) {
/* Strand Shader setting*/
float4 curvedata = kernel_tex_fetch(__curves, sd->prim);
sd->shader = __float_as_int(curvedata.z);
sd->segment = isect->segment;
float tcorr = isect->t;
if(kernel_data.curve.curveflags & CURVE_KN_POSTINTERSECTCORRECTION)
tcorr = (isect->u < 0)? tcorr + sqrtf(isect->v) : tcorr - sqrtf(isect->v);
sd->P = bvh_curve_refine(kg, sd, isect, ray, tcorr);
}
else {
#endif
/* fetch triangle data */
float4 Ns = kernel_tex_fetch(__tri_normal, sd->prim);
float3 Ng = make_float3(Ns.x, Ns.y, Ns.z);
sd->shader = __float_as_int(Ns.w);
/* fetch triangle data */
float4 Ns = kernel_tex_fetch(__tri_normal, sd->prim);
float3 Ng = make_float3(Ns.x, Ns.y, Ns.z);
sd->shader = __float_as_int(Ns.w);
#ifdef __HAIR__
sd->segment = ~0;
sd->segment = ~0;
#endif
#ifdef __UV__
sd->u = isect->u;
sd->v = isect->v;
sd->u = isect->u;
sd->v = isect->v;
#endif
/* vectors */
sd->P = bvh_triangle_refine(kg, sd, isect, ray);
sd->Ng = Ng;
sd->N = Ng;
/* smooth normal */
if(sd->shader & SHADER_SMOOTH_NORMAL)
sd->N = triangle_smooth_normal(kg, sd->prim, sd->u, sd->v);
/* vectors */
sd->P = bvh_triangle_refine_subsurface(kg, sd, isect, ray);
sd->Ng = Ng;
sd->N = Ng;
/* smooth normal */
if(sd->shader & SHADER_SMOOTH_NORMAL)
sd->N = triangle_smooth_normal(kg, sd->prim, sd->u, sd->v);
#ifdef __DPDU__
/* dPdu/dPdv */
triangle_dPdudv(kg, &sd->dPdu, &sd->dPdv, sd->prim);
#endif
#ifdef __HAIR__
}
/* dPdu/dPdv */
triangle_dPdudv(kg, &sd->dPdu, &sd->dPdv, sd->prim);
#endif
sd->flag |= kernel_tex_fetch(__shader_flag, (sd->shader & SHADER_MASK)*2);
@@ -468,6 +448,8 @@ __device_inline void shader_setup_from_background(KernelGlobals *kg, ShaderData
__device_inline void _shader_bsdf_multi_eval(KernelGlobals *kg, const ShaderData *sd, const float3 omega_in, float *pdf,
int skip_bsdf, BsdfEval *result_eval, float sum_pdf, float sum_sample_weight)
{
/* this is the veach one-sample model with balance heuristic, some pdf
* factors drop out when using balance heuristic weighting */
for(int i = 0; i< sd->num_closure; i++) {
if(i == skip_bsdf)
continue;
@@ -706,34 +688,34 @@ __device float3 shader_bsdf_subsurface(KernelGlobals *kg, ShaderData *sd)
#endif
}
__device float3 shader_bsdf_ao(KernelGlobals *kg, ShaderData *sd, float ao_factor, float3 *N)
__device float3 shader_bsdf_ao(KernelGlobals *kg, ShaderData *sd, float ao_factor, float3 *N_)
{
#ifdef __MULTI_CLOSURE__
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
*N = make_float3(0.0f, 0.0f, 0.0f);
float3 N = make_float3(0.0f, 0.0f, 0.0f);
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSDF_DIFFUSE(sc->type)) {
eval += sc->weight*ao_factor;
*N += sc->N*average(sc->weight);
N += sc->N*average(sc->weight);
}
else if(CLOSURE_IS_AMBIENT_OCCLUSION(sc->type)) {
eval += sc->weight;
*N += sd->N*average(sc->weight);
N += sd->N*average(sc->weight);
}
}
if(is_zero(*N))
*N = sd->N;
if(is_zero(N))
N = sd->N;
else
*N = normalize(*N);
N = normalize(N);
*N_ = N;
return eval;
#else
*N = sd->N;
*N_ = sd->N;
if(CLOSURE_IS_BSDF_DIFFUSE(sd->closure.type))
return sd->closure.weight*ao_factor;
@@ -744,6 +726,49 @@ __device float3 shader_bsdf_ao(KernelGlobals *kg, ShaderData *sd, float ao_facto
#endif
}
__device float3 shader_bssrdf_sum(ShaderData *sd, float3 *N_, float *texture_blur_)
{
#ifdef __MULTI_CLOSURE__
float3 eval = make_float3(0.0f, 0.0f, 0.0f);
float3 N = make_float3(0.0f, 0.0f, 0.0f);
float texture_blur = 0.0f, weight_sum = 0.0f;
for(int i = 0; i< sd->num_closure; i++) {
ShaderClosure *sc = &sd->closure[i];
if(CLOSURE_IS_BSSRDF(sc->type)) {
float avg_weight = fabsf(average(sc->weight));
N += sc->N*avg_weight;
eval += sc->weight;
texture_blur += sc->data1*avg_weight;
weight_sum += avg_weight;
}
}
if(N_)
*N_ = (is_zero(N))? sd->N: normalize(N);
if(texture_blur_)
*texture_blur_ = texture_blur/weight_sum;
return eval;
#else
if(CLOSURE_IS_BSSRDF(sd->closure.type)) {
if(N_) *N_ = sd->closure.N;
if(texture_blur_) *texture_blur_ = sd->closure.data1;
return sd->closure.weight;
}
else {
if(N_) *N_ = sd->N;
if(texture_blur_) *texture_blur_ = 0.0f;
return make_float3(0.0f, 0.0f, 0.0f);
}
#endif
}
/* Emission */
__device float3 emissive_eval(KernelGlobals *kg, ShaderData *sd, ShaderClosure *sc)