1 files changed, 179 insertions, 0 deletions
diff --git a/thirdparty/embree/kernels/common/instance_stack.h b/thirdparty/embree/kernels/common/instance_stack.h
new file mode 100644
index 0000000000..d3c0a643f1
--- /dev/null
+++ b/thirdparty/embree/kernels/common/instance_stack.h
@@ -0,0 +1,179 @@
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "rtcore.h"
+
+namespace embree {
+namespace instance_id_stack {
+
+static_assert(RTC_MAX_INSTANCE_LEVEL_COUNT > 0, 
+              "RTC_MAX_INSTANCE_LEVEL_COUNT must be greater than 0.");
+
+/*******************************************************************************
+ * Instance ID stack manipulation.
+ * This is used from the instance intersector.
+ ******************************************************************************/
+
+/* 
+ * Push an instance to the stack. 
+ */
+RTC_FORCEINLINE bool push(RTCIntersectContext* context, 
+                          unsigned instanceId)
+{
+#if RTC_MAX_INSTANCE_LEVEL_COUNT > 1
+  const bool spaceAvailable = context->instStackSize < RTC_MAX_INSTANCE_LEVEL_COUNT;
+  /* We assert here because instances are silently dropped when the stack is full. 
+     This might be quite hard to find in production. */
+  assert(spaceAvailable); 
+  if (likely(spaceAvailable))
+    context->instID[context->instStackSize++] = instanceId;
+  return spaceAvailable;
+#else
+  const bool spaceAvailable = (context->instID[0] == RTC_INVALID_GEOMETRY_ID);
+  assert(spaceAvailable); 
+  if (likely(spaceAvailable))
+    context->instID[0] = instanceId;
+  return spaceAvailable;
+#endif
+}
+
+
+/* 
+ * Pop the last instance pushed to the stack. 
+ * Do not call on an empty stack. 
+ */
+RTC_FORCEINLINE void pop(RTCIntersectContext* context)
+{
+  assert(context);
+#if RTC_MAX_INSTANCE_LEVEL_COUNT > 1
+  assert(context->instStackSize > 0);
+  context->instID[--context->instStackSize] = RTC_INVALID_GEOMETRY_ID;
+#else
+  assert(context->instID[0] != RTC_INVALID_GEOMETRY_ID);
+  context->instID[0] = RTC_INVALID_GEOMETRY_ID;
+#endif
+}
+
+/*
+ * Optimized instance id stack copy.
+ * The copy() functions will either copy full
+ * stacks or copy only until the last valid element has been copied, depending
+ * on RTC_MAX_INSTANCE_LEVEL_COUNT.
+ */
+RTC_FORCEINLINE void copy_UU(const unsigned* src, unsigned* tgt)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  tgt[0] = src[0];
+  
+#else
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    tgt[l] = src[l];
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4)
+      if (src[l] == RTC_INVALID_GEOMETRY_ID)
+        break;
+  }
+#endif
+}
+
+template <int K>
+RTC_FORCEINLINE void copy_UV(const unsigned* src, vuint<K>* tgt)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  tgt[0] = src[0];
+
+#else
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    tgt[l] = src[l];
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4)
+      if (src[l] == RTC_INVALID_GEOMETRY_ID)
+        break;
+  }
+#endif
+}
+
+template <int K>
+RTC_FORCEINLINE void copy_UV(const unsigned* src, vuint<K>* tgt, size_t j)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  tgt[0][j] = src[0];
+
+#else
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    tgt[l][j] = src[l];
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4)
+      if (src[l] == RTC_INVALID_GEOMETRY_ID)
+        break;
+  }
+#endif
+}
+
+template <int K>
+RTC_FORCEINLINE void copy_UV(const unsigned* src, vuint<K>* tgt, const vbool<K>& mask)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  vuint<K>::store(mask, tgt, src[0]);
+
+#else
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    vuint<K>::store(mask, tgt + l, src[l]);
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4)
+      if (src[l] == RTC_INVALID_GEOMETRY_ID)
+        break;
+  }
+#endif
+}
+
+template <int K>
+RTC_FORCEINLINE void copy_VU(const vuint<K>* src, unsigned* tgt, size_t i)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  tgt[0] = src[0][i];
+
+#else
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    tgt[l] = src[l][i];
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4)
+      if (src[l][i] == RTC_INVALID_GEOMETRY_ID)
+        break;
+  }
+#endif
+}
+
+template <int K>
+RTC_FORCEINLINE void copy_VV(const vuint<K>* src, vuint<K>* tgt, size_t i, size_t j)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  tgt[0][j] = src[0][i];
+
+#else
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    tgt[l][j] = src[l][i];
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4)
+      if (src[l][i] == RTC_INVALID_GEOMETRY_ID)
+        break;
+  }
+#endif
+}
+
+template <int K>
+RTC_FORCEINLINE void copy_VV(const vuint<K>* src, vuint<K>* tgt, const vbool<K>& mask)
+{
+#if (RTC_MAX_INSTANCE_LEVEL_COUNT == 1)
+  vuint<K>::store(mask, tgt, src[0]);
+
+#else
+  vbool<K> done = !mask;
+  for (unsigned l = 0; l < RTC_MAX_INSTANCE_LEVEL_COUNT; ++l) {
+    vuint<K>::store(mask, tgt + l, src[l]);
+    if (RTC_MAX_INSTANCE_LEVEL_COUNT > 4) {
+      done |= src[l] == RTC_INVALID_GEOMETRY_ID;
+      if (all(done)) break;
+    }
+  }
+#endif
+}
+
+} // namespace instance_id_stack
+} // namespace embree