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path: root/intern/cycles/kernel/kernel_jitter.h
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-rw-r--r--intern/cycles/kernel/kernel_jitter.h252
1 files changed, 94 insertions, 158 deletions
diff --git a/intern/cycles/kernel/kernel_jitter.h b/intern/cycles/kernel/kernel_jitter.h
index f4e60a807f7..354e8115538 100644
--- a/intern/cycles/kernel/kernel_jitter.h
+++ b/intern/cycles/kernel/kernel_jitter.h
@@ -14,93 +14,27 @@
* limitations under the License.
*/
-/* TODO(sergey): Consider moving portable ctz/clz stuff to util. */
-
+#pragma once
CCL_NAMESPACE_BEGIN
-/* "Correlated Multi-Jittered Sampling"
- * Andrew Kensler, Pixar Technical Memo 13-01, 2013 */
-
-/* TODO: find good value, suggested 64 gives pattern on cornell box ceiling. */
-#define CMJ_RANDOM_OFFSET_LIMIT 4096
-
-ccl_device_inline bool cmj_is_pow2(int i)
+ccl_device_inline uint32_t laine_karras_permutation(uint32_t x, uint32_t seed)
{
- return (i > 1) && ((i & (i - 1)) == 0);
-}
+ x += seed;
+ x ^= (x * 0x6c50b47cu);
+ x ^= x * 0xb82f1e52u;
+ x ^= x * 0xc7afe638u;
+ x ^= x * 0x8d22f6e6u;
-ccl_device_inline int cmj_fast_mod_pow2(int a, int b)
-{
- return (a & (b - 1));
+ return x;
}
-/* b must be > 1 */
-ccl_device_inline int cmj_fast_div_pow2(int a, int b)
+ccl_device_inline uint32_t nested_uniform_scramble(uint32_t x, uint32_t seed)
{
- kernel_assert(b > 1);
- return a >> count_trailing_zeros(b);
-}
+ x = reverse_integer_bits(x);
+ x = laine_karras_permutation(x, seed);
+ x = reverse_integer_bits(x);
-ccl_device_inline uint cmj_w_mask(uint w)
-{
- kernel_assert(w > 1);
- return ((1 << (32 - count_leading_zeros(w))) - 1);
-}
-
-ccl_device_inline uint cmj_permute(uint i, uint l, uint p)
-{
- uint w = l - 1;
-
- if ((l & w) == 0) {
- /* l is a power of two (fast) */
- i ^= p;
- i *= 0xe170893d;
- i ^= p >> 16;
- i ^= (i & w) >> 4;
- i ^= p >> 8;
- i *= 0x0929eb3f;
- i ^= p >> 23;
- i ^= (i & w) >> 1;
- i *= 1 | p >> 27;
- i *= 0x6935fa69;
- i ^= (i & w) >> 11;
- i *= 0x74dcb303;
- i ^= (i & w) >> 2;
- i *= 0x9e501cc3;
- i ^= (i & w) >> 2;
- i *= 0xc860a3df;
- i &= w;
- i ^= i >> 5;
-
- return (i + p) & w;
- }
- else {
- /* l is not a power of two (slow) */
- w = cmj_w_mask(w);
-
- do {
- i ^= p;
- i *= 0xe170893d;
- i ^= p >> 16;
- i ^= (i & w) >> 4;
- i ^= p >> 8;
- i *= 0x0929eb3f;
- i ^= p >> 23;
- i ^= (i & w) >> 1;
- i *= 1 | p >> 27;
- i *= 0x6935fa69;
- i ^= (i & w) >> 11;
- i *= 0x74dcb303;
- i ^= (i & w) >> 2;
- i *= 0x9e501cc3;
- i ^= (i & w) >> 2;
- i *= 0xc860a3df;
- i &= w;
- i ^= i >> 5;
- } while (i >= l);
-
- return (i + p) % l;
- }
+ return x;
}
ccl_device_inline uint cmj_hash(uint i, uint p)
@@ -133,99 +67,101 @@ ccl_device_inline float cmj_randfloat(uint i, uint p)
return cmj_hash(i, p) * (1.0f / 4294967808.0f);
}
-#ifdef __CMJ__
-ccl_device float cmj_sample_1D(int s, int N, int p)
+ccl_device_inline float cmj_randfloat_simple(uint i, uint p)
{
- kernel_assert(s < N);
-
- uint x = cmj_permute(s, N, p * 0x68bc21eb);
- float jx = cmj_randfloat(s, p * 0x967a889b);
-
- float invN = 1.0f / N;
- return (x + jx) * invN;
+ return cmj_hash_simple(i, p) * (1.0f / (float)0xFFFFFFFF);
}
-/* TODO(sergey): Do some extra tests and consider moving to util_math.h. */
-ccl_device_inline int cmj_isqrt(int value)
+ccl_device float pmj_sample_1D(const KernelGlobals *kg, uint sample, uint rng_hash, uint dimension)
{
-# if defined(__KERNEL_CUDA__)
- return float_to_int(__fsqrt_ru(value));
-# elif defined(__KERNEL_GPU__)
- return float_to_int(sqrtf(value));
-# else
- /* This is a work around for fast-math on CPU which might replace sqrtf()
- * with am approximated version.
- */
- return float_to_int(sqrtf(value) + 1e-6f);
-# endif
-}
+ /* The PMJ sample sets contain a sample with (x,y) with NUM_PMJ_SAMPLES so for 1D
+ * the x part is used as the sample (TODO(@leesonw): Add using both x and y parts
+ * independently). */
+
+ /* Perform Owen shuffle of the sample number to reorder the samples. */
+#ifdef _SIMPLE_HASH_
+ const uint rv = cmj_hash_simple(dimension, rng_hash);
+#else /* Use a _REGULAR_HASH_. */
+ const uint rv = cmj_hash(dimension, rng_hash);
+#endif
+#ifdef _XOR_SHUFFLE_
+# warning "Using XOR shuffle."
+ const uint s = sample ^ rv;
+#else /* Use _OWEN_SHUFFLE_ for reordering. */
+ const uint s = nested_uniform_scramble(sample, rv);
+#endif
-ccl_device void cmj_sample_2D(int s, int N, int p, float *fx, float *fy)
-{
- kernel_assert(s < N);
+ /* Based on the sample number a sample pattern is selected and offset by the dimension. */
+ const uint sample_set = s / NUM_PMJ_SAMPLES;
+ const uint d = (dimension + sample_set);
+ const uint dim = d % NUM_PMJ_PATTERNS;
+ int index = 2 * (dim * NUM_PMJ_SAMPLES + (s % NUM_PMJ_SAMPLES));
+
+ float fx = kernel_tex_fetch(__sample_pattern_lut, index);
- int m = cmj_isqrt(N);
- int n = (N - 1) / m + 1;
- float invN = 1.0f / N;
- float invm = 1.0f / m;
- float invn = 1.0f / n;
+#ifndef _NO_CRANLEY_PATTERSON_ROTATION_
+ /* Use Cranley-Patterson rotation to displace the sample pattern. */
+# ifdef _SIMPLE_HASH_
+ float dx = cmj_randfloat_simple(d, rng_hash);
+# else
+ /* Only jitter within the grid interval. */
+ float dx = cmj_randfloat(d, rng_hash);
+# endif
+ fx = fx + dx * (1.0f / NUM_PMJ_SAMPLES);
+ fx = fx - floorf(fx);
- s = cmj_permute(s, N, p * 0x51633e2d);
+#else
+# warning "Not using Cranley-Patterson Rotation."
+#endif
- int sdivm, smodm;
+ return fx;
+}
- if (cmj_is_pow2(m)) {
- sdivm = cmj_fast_div_pow2(s, m);
- smodm = cmj_fast_mod_pow2(s, m);
- }
- else {
- /* Doing `s * inmv` gives precision issues here. */
- sdivm = s / m;
- smodm = s - sdivm * m;
- }
+ccl_device void pmj_sample_2D(
+ const KernelGlobals *kg, uint sample, uint rng_hash, uint dimension, float *x, float *y)
+{
+ /* Perform a shuffle on the sample number to reorder the samples. */
+#ifdef _SIMPLE_HASH_
+ const uint rv = cmj_hash_simple(dimension, rng_hash);
+#else /* Use a _REGULAR_HASH_. */
+ const uint rv = cmj_hash(dimension, rng_hash);
+#endif
+#ifdef _XOR_SHUFFLE_
+# warning "Using XOR shuffle."
+ const uint s = sample ^ rv;
+#else /* Use _OWEN_SHUFFLE_ for reordering. */
+ const uint s = nested_uniform_scramble(sample, rv);
+#endif
- uint sx = cmj_permute(smodm, m, p * 0x68bc21eb);
- uint sy = cmj_permute(sdivm, n, p * 0x02e5be93);
+ /* Based on the sample number a sample pattern is selected and offset by the dimension. */
+ const uint sample_set = s / NUM_PMJ_SAMPLES;
+ const uint d = (dimension + sample_set);
+ const uint dim = d % NUM_PMJ_PATTERNS;
+ int index = 2 * (dim * NUM_PMJ_SAMPLES + (s % NUM_PMJ_SAMPLES));
- float jx = cmj_randfloat(s, p * 0x967a889b);
- float jy = cmj_randfloat(s, p * 0x368cc8b7);
+ float fx = kernel_tex_fetch(__sample_pattern_lut, index);
+ float fy = kernel_tex_fetch(__sample_pattern_lut, index + 1);
- *fx = (sx + (sy + jx) * invn) * invm;
- *fy = (s + jy) * invN;
-}
+#ifndef _NO_CRANLEY_PATTERSON_ROTATION_
+ /* Use Cranley-Patterson rotation to displace the sample pattern. */
+# ifdef _SIMPLE_HASH_
+ float dx = cmj_randfloat_simple(d, rng_hash);
+ float dy = cmj_randfloat_simple(d + 1, rng_hash);
+# else
+ float dx = cmj_randfloat(d, rng_hash);
+ float dy = cmj_randfloat(d + 1, rng_hash);
+# endif
+ /* Only jitter within the grid cells. */
+ fx = fx + dx * (1.0f / NUM_PMJ_DIVISIONS);
+ fy = fy + dy * (1.0f / NUM_PMJ_DIVISIONS);
+ fx = fx - floorf(fx);
+ fy = fy - floorf(fy);
+#else
+# warning "Not using Cranley Patterson Rotation."
#endif
-ccl_device float pmj_sample_1D(KernelGlobals *kg, int sample, int rng_hash, int dimension)
-{
- /* Fallback to random */
- if (sample >= NUM_PMJ_SAMPLES) {
- const int p = rng_hash + dimension;
- return cmj_randfloat(sample, p);
- }
- else {
- const uint mask = cmj_hash_simple(dimension, rng_hash) & 0x007fffff;
- const int index = ((dimension % NUM_PMJ_PATTERNS) * NUM_PMJ_SAMPLES + sample) * 2;
- return __uint_as_float(kernel_tex_fetch(__sample_pattern_lut, index) ^ mask) - 1.0f;
- }
-}
-
-ccl_device float2 pmj_sample_2D(KernelGlobals *kg, int sample, int rng_hash, int dimension)
-{
- if (sample >= NUM_PMJ_SAMPLES) {
- const int p = rng_hash + dimension;
- const float fx = cmj_randfloat(sample, p);
- const float fy = cmj_randfloat(sample, p + 1);
- return make_float2(fx, fy);
- }
- else {
- const int index = ((dimension % NUM_PMJ_PATTERNS) * NUM_PMJ_SAMPLES + sample) * 2;
- const uint maskx = cmj_hash_simple(dimension, rng_hash) & 0x007fffff;
- const uint masky = cmj_hash_simple(dimension + 1, rng_hash) & 0x007fffff;
- const float fx = __uint_as_float(kernel_tex_fetch(__sample_pattern_lut, index) ^ maskx) - 1.0f;
- const float fy = __uint_as_float(kernel_tex_fetch(__sample_pattern_lut, index + 1) ^ masky) -
- 1.0f;
- return make_float2(fx, fy);
- }
+ (*x) = fx;
+ (*y) = fy;
}
CCL_NAMESPACE_END
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