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Cycles: initialize LCG for sss and hair sampling without using the sobol sampler,

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slightly faster but also fixes the u/v sampling dimensions not longer being at even
values which is needed for best results.
This commit is contained in:
Brecht Van Lommel
2013-04-17 14:48:01 +00:00
parent cf0e457e52
commit 45552a4595
3 changed files with 8 additions and 11 deletions
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12
intern/cycles/kernel/kernel_path.h
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@@ -258,8 +258,7 @@ __device float4 kernel_path_progressive(KernelGlobals *kg, RNG *rng, int sample,
difl = kernel_data.curve_kernel_data.minimum_width * len(pixdiff) * 0.5f; difl = kernel_data.curve_kernel_data.minimum_width * len(pixdiff) * 0.5f;
} }
float extmax = kernel_data.curve_kernel_data.maximum_width; float extmax = kernel_data.curve_kernel_data.maximum_width;
float rng_hair_seed = path_rng(kg, rng, sample, rng_offset + PRNG_HAIR); uint lcg_state = lcg_init(*rng + rng_offset + sample);
uint lcg_state = lcg_init(rng_hair_seed);
bool hit = scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax); bool hit = scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax);
#else #else
@@ -377,7 +376,7 @@ __device float4 kernel_path_progressive(KernelGlobals *kg, RNG *rng, int sample,
/* do bssrdf scatter step if we picked a bssrdf closure */ /* do bssrdf scatter step if we picked a bssrdf closure */
if(sc) { if(sc) {
uint lcg_state = lcg_init(rbsdf); uint lcg_state = lcg_init(*rng + rng_offset + sample);
subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, false); subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, false);
} }
} }
@@ -601,7 +600,7 @@ __device void kernel_path_indirect(KernelGlobals *kg, RNG *rng, int sample, Ray
/* do bssrdf scatter step if we picked a bssrdf closure */ /* do bssrdf scatter step if we picked a bssrdf closure */
if(sc) { if(sc) {
uint lcg_state = lcg_init(rbsdf); uint lcg_state = lcg_init(*rng + rng_offset + sample);
subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, false); subsurface_scatter_step(kg, &sd, state.flag, sc, &lcg_state, false);
} }
} }
@@ -930,8 +929,7 @@ __device float4 kernel_path_non_progressive(KernelGlobals *kg, RNG *rng, int sam
difl = kernel_data.curve_kernel_data.minimum_width * len(pixdiff) * 0.5f; difl = kernel_data.curve_kernel_data.minimum_width * len(pixdiff) * 0.5f;
} }
float extmax = kernel_data.curve_kernel_data.maximum_width; float extmax = kernel_data.curve_kernel_data.maximum_width;
float rng_hair_seed = path_rng(kg, rng, sample, rng_offset + PRNG_HAIR); uint lcg_state = lcg_init(*rng + rng_offset + sample);
uint lcg_state = lcg_init(rng_hair_seed);
if(!scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax)) { if(!scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax)) {
#else #else
@@ -1017,7 +1015,7 @@ __device float4 kernel_path_non_progressive(KernelGlobals *kg, RNG *rng, int sam
continue; continue;
/* set up random number generator */ /* set up random number generator */
uint lcg_state = lcg_init(rbsdf); uint lcg_state = lcg_init(*rng + rng_offset + sample);
int num_samples = kernel_data.integrator.subsurface_samples; int num_samples = kernel_data.integrator.subsurface_samples;
float num_samples_inv = 1.0f/num_samples; float num_samples_inv = 1.0f/num_samples;

4
intern/cycles/kernel/kernel_random.h
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@@ -207,9 +207,9 @@ __device float lcg_step(uint *rng)
return (float)*rng * (1.0f/(float)0xFFFFFFFF); return (float)*rng * (1.0f/(float)0xFFFFFFFF);
} }
__device uint lcg_init(float seed) __device uint lcg_init(uint seed)
{ {
uint rng = __float_as_int(seed); uint rng = seed;
lcg_step(&rng); lcg_step(&rng);
return rng; return rng;
} }

3
intern/cycles/kernel/kernel_types.h
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@@ -159,8 +159,7 @@ enum PathTraceDimension {
PRNG_LIGHT_V = 5, PRNG_LIGHT_V = 5,
PRNG_LIGHT_F = 6, PRNG_LIGHT_F = 6,
PRNG_TERMINATE = 7, PRNG_TERMINATE = 7,
PRNG_HAIR = 8, PRNG_BOUNCE_NUM = 8
PRNG_BOUNCE_NUM = 9
}; };
/* these flags values correspond to raytypes in osl.cpp, so keep them in sync! /* these flags values correspond to raytypes in osl.cpp, so keep them in sync!