diff options
Diffstat (limited to 'intern/cycles/kernel/closure/bssrdf.h')
-rw-r--r-- | intern/cycles/kernel/closure/bssrdf.h | 78 |
1 files changed, 34 insertions, 44 deletions
diff --git a/intern/cycles/kernel/closure/bssrdf.h b/intern/cycles/kernel/closure/bssrdf.h index 267aeea6e86..6791c0b83cc 100644 --- a/intern/cycles/kernel/closure/bssrdf.h +++ b/intern/cycles/kernel/closure/bssrdf.h @@ -39,12 +39,11 @@ typedef ccl_addr_space struct Bssrdf { /* paper suggests 1/12.46 which is much too small, suspect it's *12.46 */ #define GAUSS_TRUNCATE 12.46f -ccl_device float bssrdf_gaussian_eval(const ShaderClosure *sc, float r) +ccl_device float bssrdf_gaussian_eval(const float radius, float r) { /* integrate (2*pi*r * exp(-r*r/(2*v)))/(2*pi*v)) from 0 to Rm * = 1 - exp(-Rm*Rm/(2*v)) */ - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float v = bssrdf->radius*bssrdf->radius*(0.25f*0.25f); + const float v = radius*radius*(0.25f*0.25f); const float Rm = sqrtf(v*GAUSS_TRUNCATE); if(r >= Rm) @@ -53,20 +52,19 @@ ccl_device float bssrdf_gaussian_eval(const ShaderClosure *sc, float r) return expf(-r*r/(2.0f*v))/(2.0f*M_PI_F*v); } -ccl_device float bssrdf_gaussian_pdf(const ShaderClosure *sc, float r) +ccl_device float bssrdf_gaussian_pdf(const float radius, float r) { /* 1.0 - expf(-Rm*Rm/(2*v)) simplified */ const float area_truncated = 1.0f - expf(-0.5f*GAUSS_TRUNCATE); - return bssrdf_gaussian_eval(sc, r) * (1.0f/(area_truncated)); + return bssrdf_gaussian_eval(radius, r) * (1.0f/(area_truncated)); } -ccl_device void bssrdf_gaussian_sample(const ShaderClosure *sc, float xi, float *r, float *h) +ccl_device void bssrdf_gaussian_sample(const float radius, float xi, float *r, float *h) { /* xi = integrate (2*pi*r * exp(-r*r/(2*v)))/(2*pi*v)) = -exp(-r^2/(2*v)) * r = sqrt(-2*v*logf(xi)) */ - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float v = bssrdf->radius*bssrdf->radius*(0.25f*0.25f); + const float v = radius*radius*(0.25f*0.25f); const float Rm = sqrtf(v*GAUSS_TRUNCATE); /* 1.0 - expf(-Rm*Rm/(2*v)) simplified */ @@ -87,13 +85,10 @@ ccl_device void bssrdf_gaussian_sample(const ShaderClosure *sc, float xi, float * far as I can tell has no closed form solution. So we get an iterative solution * instead with newton-raphson. */ -ccl_device float bssrdf_cubic_eval(const ShaderClosure *sc, float r) +ccl_device float bssrdf_cubic_eval(const float radius, const float sharpness, float r) { - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float sharpness = bssrdf->sharpness; - if(sharpness == 0.0f) { - const float Rm = bssrdf->radius; + const float Rm = radius; if(r >= Rm) return 0.0f; @@ -107,7 +102,7 @@ ccl_device float bssrdf_cubic_eval(const ShaderClosure *sc, float r) } else { - float Rm = bssrdf->radius*(1.0f + sharpness); + float Rm = radius*(1.0f + sharpness); if(r >= Rm) return 0.0f; @@ -135,9 +130,9 @@ ccl_device float bssrdf_cubic_eval(const ShaderClosure *sc, float r) } } -ccl_device float bssrdf_cubic_pdf(const ShaderClosure *sc, float r) +ccl_device float bssrdf_cubic_pdf(const float radius, const float sharpness, float r) { - return bssrdf_cubic_eval(sc, r); + return bssrdf_cubic_eval(radius, sharpness, r); } /* solve 10x^2 - 20x^3 + 15x^4 - 4x^5 - xi == 0 */ @@ -168,11 +163,9 @@ ccl_device_forceinline float bssrdf_cubic_quintic_root_find(float xi) return x; } -ccl_device void bssrdf_cubic_sample(const ShaderClosure *sc, float xi, float *r, float *h) +ccl_device void bssrdf_cubic_sample(const float radius, const float sharpness, float xi, float *r, float *h) { - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float sharpness = bssrdf->sharpness; - float Rm = bssrdf->radius; + float Rm = radius; float r_ = bssrdf_cubic_quintic_root_find(xi); if(sharpness != 0.0f) { @@ -224,10 +217,8 @@ ccl_device void bssrdf_burley_setup(Bssrdf *bssrdf) bssrdf->d = d; } -ccl_device float bssrdf_burley_eval(const ShaderClosure *sc, float r) +ccl_device float bssrdf_burley_eval(const float d, float r) { - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float d = bssrdf->d; const float Rm = BURLEY_TRUNCATE * d; if(r >= Rm) @@ -246,9 +237,9 @@ ccl_device float bssrdf_burley_eval(const ShaderClosure *sc, float r) return (exp_r_d + exp_r_3_d) / (4.0f*d); } -ccl_device float bssrdf_burley_pdf(const ShaderClosure *sc, float r) +ccl_device float bssrdf_burley_pdf(const float d, float r) { - return bssrdf_burley_eval(sc, r) * (1.0f/BURLEY_TRUNCATE_CDF); + return bssrdf_burley_eval(d, r) * (1.0f/BURLEY_TRUNCATE_CDF); } /* Find the radius for desired CDF value. @@ -291,13 +282,11 @@ ccl_device_forceinline float bssrdf_burley_root_find(float xi) return r; } -ccl_device void bssrdf_burley_sample(const ShaderClosure *sc, +ccl_device void bssrdf_burley_sample(const float d, float xi, float *r, float *h) { - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float d = bssrdf->d; const float Rm = BURLEY_TRUNCATE * d; const float r_ = bssrdf_burley_root_find(xi * BURLEY_TRUNCATE_CDF) * d; @@ -311,29 +300,26 @@ ccl_device void bssrdf_burley_sample(const ShaderClosure *sc, * * Samples distributed over disk with no falloff, for reference. */ -ccl_device float bssrdf_none_eval(const ShaderClosure *sc, float r) +ccl_device float bssrdf_none_eval(const float radius, float r) { - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float Rm = bssrdf->radius; + const float Rm = radius; return (r < Rm)? 1.0f: 0.0f; } -ccl_device float bssrdf_none_pdf(const ShaderClosure *sc, float r) +ccl_device float bssrdf_none_pdf(const float radius, float r) { /* integrate (2*pi*r)/(pi*Rm*Rm) from 0 to Rm = 1 */ - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float Rm = bssrdf->radius; + const float Rm = radius; const float area = (M_PI_F*Rm*Rm); - return bssrdf_none_eval(sc, r) / area; + return bssrdf_none_eval(radius, r) / area; } -ccl_device void bssrdf_none_sample(const ShaderClosure *sc, float xi, float *r, float *h) +ccl_device void bssrdf_none_sample(const float radius, float xi, float *r, float *h) { /* xi = integrate (2*pi*r)/(pi*Rm*Rm) = r^2/Rm^2 * r = sqrt(xi)*Rm */ - const Bssrdf *bssrdf = (const Bssrdf*)sc; - const float Rm = bssrdf->radius; + const float Rm = radius; const float r_ = sqrtf(xi)*Rm; *r = r_; @@ -406,22 +392,26 @@ ccl_device int bssrdf_setup(Bssrdf *bssrdf, ClosureType type) ccl_device void bssrdf_sample(const ShaderClosure *sc, float xi, float *r, float *h) { + const Bssrdf *bssrdf = (const Bssrdf*)sc; + if(sc->type == CLOSURE_BSSRDF_CUBIC_ID) - bssrdf_cubic_sample(sc, xi, r, h); + bssrdf_cubic_sample(bssrdf->radius, bssrdf->sharpness, xi, r, h); else if(sc->type == CLOSURE_BSSRDF_GAUSSIAN_ID) - bssrdf_gaussian_sample(sc, xi, r, h); + bssrdf_gaussian_sample(bssrdf->radius, xi, r, h); else /*if(sc->type == CLOSURE_BSSRDF_BURLEY_ID || sc->type == CLOSURE_BSSRDF_PRINCIPLED_ID)*/ - bssrdf_burley_sample(sc, xi, r, h); + bssrdf_burley_sample(bssrdf->d, xi, r, h); } ccl_device_forceinline float bssrdf_pdf(const ShaderClosure *sc, float r) { + const Bssrdf *bssrdf = (const Bssrdf*)sc; + if(sc->type == CLOSURE_BSSRDF_CUBIC_ID) - return bssrdf_cubic_pdf(sc, r); + return bssrdf_cubic_pdf(bssrdf->radius, bssrdf->sharpness, r); else if(sc->type == CLOSURE_BSSRDF_GAUSSIAN_ID) - return bssrdf_gaussian_pdf(sc, r); + return bssrdf_gaussian_pdf(bssrdf->radius, r); else /*if(sc->type == CLOSURE_BSSRDF_BURLEY_ID || sc->type == CLOSURE_BSSRDF_PRINCIPLED_ID)*/ - return bssrdf_burley_pdf(sc, r); + return bssrdf_burley_pdf(bssrdf->d, r); } CCL_NAMESPACE_END |