Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/bvh/binning.cpp

@@ -0,0 +1,277 @@
+/* SPDX-FileCopyrightText: 2009-2011 Intel Corporation
+ * SPDX-FileCopyrightText: 2012-2022 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Adapted code from Intel Corporation. */
+
+// #define __KERNEL_SSE__
+
+#include "bvh/binning.h"
+
+#include <cstdlib>
+
+#include "util/algorithm.h"
+#include "util/boundbox.h"
+#include "util/types.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* SSE replacements */
+
+__forceinline void prefetch_L1(const void * /*ptr*/) {}
+__forceinline void prefetch_L2(const void * /*ptr*/) {}
+__forceinline void prefetch_L3(const void * /*ptr*/) {}
+__forceinline void prefetch_NTA(const void * /*ptr*/) {}
+
+template<size_t src> __forceinline float extract(const int4 &b)
+{
+  return b[src];
+}
+template<size_t dst> __forceinline const float4 insert(const float4 &a, const float b)
+{
+  float4 r = a;
+  r[dst] = b;
+  return r;
+}
+
+__forceinline int get_best_dimension(const float4 &bestSAH)
+{
+  // return (int)__bsf(movemask(reduce_min(bestSAH) == bestSAH));
+
+  const float minSAH = min(bestSAH.x, min(bestSAH.y, bestSAH.z));
+
+  if (bestSAH.x == minSAH) {
+    return 0;
+  }
+  if (bestSAH.y == minSAH) {
+    return 1;
+  }
+  return 2;
+}
+
+/* BVH Object Binning */
+
+BVHObjectBinning::BVHObjectBinning(const BVHRange &job,
+                                   BVHReference *prims,
+                                   const BVHUnaligned *unaligned_heuristic,
+                                   const Transform *aligned_space)
+    : BVHRange(job),
+      splitSAH(FLT_MAX),
+      dim(0),
+      pos(0),
+      unaligned_heuristic_(unaligned_heuristic),
+      aligned_space_(aligned_space)
+{
+  if (aligned_space_ == nullptr) {
+    bounds_ = bounds();
+    cent_bounds_ = cent_bounds();
+  }
+  else {
+    /* TODO(sergey): With some additional storage we can avoid
+     * need in re-calculating this.
+     */
+    bounds_ = unaligned_heuristic->compute_aligned_boundbox(
+        *this, prims, *aligned_space, &cent_bounds_);
+  }
+
+  /* compute number of bins to use and precompute scaling factor for binning */
+  num_bins = min(size_t(MAX_BINS), size_t(4.0f + 0.05f * size()));
+  scale = safe_divide(make_float3((float)num_bins), cent_bounds_.size());
+
+  /* initialize binning counter and bounds */
+  BoundBox bin_bounds[MAX_BINS][4]; /* bounds for every bin in every dimension */
+  int4 bin_count[MAX_BINS];         /* number of primitives mapped to bin */
+
+  for (size_t i = 0; i < num_bins; i++) {
+    bin_count[i] = make_int4(0);
+    bin_bounds[i][0] = bin_bounds[i][1] = bin_bounds[i][2] = BoundBox::empty;
+  }
+
+  /* map geometry to bins, unrolled once */
+  {
+    int64_t i;
+
+    for (i = 0; i < int64_t(size()) - 1; i += 2) {
+      prefetch_L2(&prims[start() + i + 8]);
+
+      /* map even and odd primitive to bin */
+      const BVHReference &prim0 = prims[start() + i + 0];
+      const BVHReference &prim1 = prims[start() + i + 1];
+
+      const BoundBox bounds0 = get_prim_bounds(prim0);
+      const BoundBox bounds1 = get_prim_bounds(prim1);
+
+      const int4 bin0 = get_bin(bounds0);
+      const int4 bin1 = get_bin(bounds1);
+
+      /* increase bounds for bins for even primitive */
+      const int b00 = (int)extract<0>(bin0);
+      bin_count[b00][0]++;
+      bin_bounds[b00][0].grow(bounds0);
+      const int b01 = (int)extract<1>(bin0);
+      bin_count[b01][1]++;
+      bin_bounds[b01][1].grow(bounds0);
+      const int b02 = (int)extract<2>(bin0);
+      bin_count[b02][2]++;
+      bin_bounds[b02][2].grow(bounds0);
+
+      /* increase bounds of bins for odd primitive */
+      const int b10 = (int)extract<0>(bin1);
+      bin_count[b10][0]++;
+      bin_bounds[b10][0].grow(bounds1);
+      const int b11 = (int)extract<1>(bin1);
+      bin_count[b11][1]++;
+      bin_bounds[b11][1].grow(bounds1);
+      const int b12 = (int)extract<2>(bin1);
+      bin_count[b12][2]++;
+      bin_bounds[b12][2].grow(bounds1);
+    }
+
+    /* for uneven number of primitives */
+    if (i < int64_t(size())) {
+      /* map primitive to bin */
+      const BVHReference &prim0 = prims[start() + i];
+      const BoundBox bounds0 = get_prim_bounds(prim0);
+      const int4 bin0 = get_bin(bounds0);
+
+      /* increase bounds of bins */
+      const int b00 = (int)extract<0>(bin0);
+      bin_count[b00][0]++;
+      bin_bounds[b00][0].grow(bounds0);
+      const int b01 = (int)extract<1>(bin0);
+      bin_count[b01][1]++;
+      bin_bounds[b01][1].grow(bounds0);
+      const int b02 = (int)extract<2>(bin0);
+      bin_count[b02][2]++;
+      bin_bounds[b02][2].grow(bounds0);
+    }
+  }
+
+  /* sweep from right to left and compute parallel prefix of merged bounds */
+  float4 r_area[MAX_BINS];  /* area of bounds of primitives on the right */
+  float4 r_count[MAX_BINS]; /* number of primitives on the right */
+  int4 count = make_int4(0);
+
+  BoundBox bx = BoundBox::empty;
+  BoundBox by = BoundBox::empty;
+  BoundBox bz = BoundBox::empty;
+
+  for (size_t i = num_bins - 1; i > 0; i--) {
+    count = count + bin_count[i];
+    r_count[i] = blocks(count);
+
+    bx = merge(bx, bin_bounds[i][0]);
+    r_area[i][0] = bx.half_area();
+    by = merge(by, bin_bounds[i][1]);
+    r_area[i][1] = by.half_area();
+    bz = merge(bz, bin_bounds[i][2]);
+    r_area[i][2] = bz.half_area();
+    r_area[i][3] = r_area[i][2];
+  }
+
+  /* sweep from left to right and compute SAH */
+  int4 ii = make_int4(1);
+  float4 bestSAH = make_float4(FLT_MAX);
+  int4 bestSplit = make_int4(-1);
+
+  count = make_int4(0);
+
+  bx = BoundBox::empty;
+  by = BoundBox::empty;
+  bz = BoundBox::empty;
+
+  for (size_t i = 1; i < num_bins; i++, ii += make_int4(1)) {
+    count = count + bin_count[i - 1];
+
+    bx = merge(bx, bin_bounds[i - 1][0]);
+    const float Ax = bx.half_area();
+    by = merge(by, bin_bounds[i - 1][1]);
+    const float Ay = by.half_area();
+    bz = merge(bz, bin_bounds[i - 1][2]);
+    const float Az = bz.half_area();
+
+    const float4 lCount = blocks(count);
+    const float4 lArea = make_float4(Ax, Ay, Az, Az);
+    const float4 sah = lArea * lCount + r_area[i] * r_count[i];
+
+    bestSplit = select(sah < bestSAH, ii, bestSplit);
+    bestSAH = min(sah, bestSAH);
+  }
+
+  const int4 mask = make_float4(cent_bounds_.size()) <= zero_float4();
+  bestSAH = insert<3>(select(mask, make_float4(FLT_MAX), bestSAH), FLT_MAX);
+
+  /* find best dimension */
+  dim = get_best_dimension(bestSAH);
+  splitSAH = bestSAH[dim];
+  pos = bestSplit[dim];
+  leafSAH = bounds_.half_area() * blocks(size());
+}
+
+void BVHObjectBinning::split(BVHReference *prims,
+                             BVHObjectBinning &left_o,
+                             BVHObjectBinning &right_o) const
+{
+  const size_t N = size();
+
+  BoundBox lgeom_bounds = BoundBox::empty;
+  BoundBox rgeom_bounds = BoundBox::empty;
+  BoundBox lcent_bounds = BoundBox::empty;
+  BoundBox rcent_bounds = BoundBox::empty;
+
+  int64_t l = 0;
+  int64_t r = N - 1;
+
+  while (l <= r) {
+    prefetch_L2(&prims[start() + l + 8]);
+    prefetch_L2(&prims[start() + r - 8]);
+
+    const BVHReference prim = prims[start() + l];
+    const BoundBox unaligned_bounds = get_prim_bounds(prim);
+    const float3 unaligned_center = unaligned_bounds.center2();
+    const float3 center = prim.bounds().center2();
+
+    if (get_bin(unaligned_center)[dim] < pos) {
+      lgeom_bounds.grow(prim.bounds());
+      lcent_bounds.grow(center);
+      l++;
+    }
+    else {
+      rgeom_bounds.grow(prim.bounds());
+      rcent_bounds.grow(center);
+      swap(prims[start() + l], prims[start() + r]);
+      r--;
+    }
+  }
+  /* finish */
+  if (l != 0 && N - 1 - r != 0) {
+    right_o = BVHObjectBinning(BVHRange(rgeom_bounds, rcent_bounds, start() + l, N - 1 - r),
+                               prims);
+    left_o = BVHObjectBinning(BVHRange(lgeom_bounds, lcent_bounds, start(), l), prims);
+    return;
+  }
+
+  /* object medium split if we did not make progress, can happen when all
+   * primitives have same centroid */
+  lgeom_bounds = BoundBox::empty;
+  rgeom_bounds = BoundBox::empty;
+  lcent_bounds = BoundBox::empty;
+  rcent_bounds = BoundBox::empty;
+
+  for (size_t i = 0; i < N / 2; i++) {
+    lgeom_bounds.grow(prims[start() + i].bounds());
+    lcent_bounds.grow(prims[start() + i].bounds().center2());
+  }
+
+  for (size_t i = N / 2; i < N; i++) {
+    rgeom_bounds.grow(prims[start() + i].bounds());
+    rcent_bounds.grow(prims[start() + i].bounds().center2());
+  }
+
+  right_o = BVHObjectBinning(BVHRange(rgeom_bounds, rcent_bounds, start() + N / 2, N / 2 + N % 2),
+                             prims);
+  left_o = BVHObjectBinning(BVHRange(lgeom_bounds, lcent_bounds, start(), N / 2), prims);
+}
+
+CCL_NAMESPACE_END