Particles: spawn particles on mesh surface

5 files changed, 164 insertions, 2 deletions

diff --git a/source/blender/blenlib/BLI_float3.hh b/source/blender/blenlib/BLI_float3.hh
index b2633985ac7..13ec563578b 100644
--- a/source/blender/blenlib/BLI_float3.hh
+++ b/source/blender/blenlib/BLI_float3.hh
@@ -143,6 +143,17 @@ struct float3 {
     return normalize_v3(*this);
   }
 
+  /**
+   * Normalizes the vector inplace.
+   */
+  void normalize()
+  {
+    normalize_v3(*this);
+  }
+
+  /**
+   * Returns a normalized vector. The original vector is not changed.
+   */
   float3 normalized() const
   {
     float3 result;
diff --git a/source/blender/blenlib/BLI_float4x4.hh b/source/blender/blenlib/BLI_float4x4.hh
index 185cffd13ac..5698d06f05d 100644
--- a/source/blender/blenlib/BLI_float4x4.hh
+++ b/source/blender/blenlib/BLI_float4x4.hh
@@ -71,8 +71,8 @@ struct float4x4 {
 
   float4x4 inverted() const
   {
-    float result[4][4];
-    invert_m4_m4(result, values);
+    float4x4 result;
+    invert_m4_m4(result.values, values);
     return result;
   }
 
@@ -86,6 +86,13 @@ struct float4x4 {
     return this->inverted();
   }
 
+  float4x4 transposed() const
+  {
+    float4x4 result;
+    transpose_m4_m4(result.values, values);
+    return result;
+  }
+
   struct float3x3_ref {
     const float4x4 &data;
 
diff --git a/source/blender/blenlib/BLI_rand.hh b/source/blender/blenlib/BLI_rand.hh
index 612ac0bbe19..7a98ee0f2bb 100644
--- a/source/blender/blenlib/BLI_rand.hh
+++ b/source/blender/blenlib/BLI_rand.hh
@@ -63,6 +63,15 @@ class RandomNumberGenerator {
   }
 
   /**
+   * \return Random value (0..N), but never N.
+   */
+  int32_t get_int32(int32_t max_exclusive)
+  {
+    BLI_assert(max_exclusive > 0);
+    return this->get_int32() % max_exclusive;
+  }
+
+  /**
    * \return Random value (0..1), but never 1.0.
    */
   double get_double()
@@ -78,6 +87,35 @@ class RandomNumberGenerator {
     return (float)this->get_int32() / 0x80000000;
   }
 
+  template<typename T> void shuffle(MutableSpan<T> values)
+  {
+    /* Cannot shuffle arrays of this size yet. */
+    BLI_assert(values.size() <= INT32_MAX);
+
+    for (int i = values.size() - 1; i >= 2; i--) {
+      int j = this->get_int32(i);
+      if (i != j) {
+        std::swap(values[i], values[j]);
+      }
+    }
+  }
+
+  /**
+   * Compute uniformly distributed barycentric coordinates.
+   */
+  float3 get_barycentric_coordinates()
+  {
+    float rand1 = this->get_float();
+    float rand2 = this->get_float();
+
+    if (rand1 + rand2 > 1.0f) {
+      rand1 = 1.0f - rand1;
+      rand2 = 1.0f - rand2;
+    }
+
+    return float3(rand1, rand2, 1.0f - rand1 - rand2);
+  }
+
   float2 get_unit_float2();
   float3 get_unit_float3();
   float2 get_triangle_sample(float2 v1, float2 v2, float2 v3);
diff --git a/source/blender/blenlib/BLI_vector_adaptor.hh b/source/blender/blenlib/BLI_vector_adaptor.hh
new file mode 100644
index 00000000000..cadffc0b445
--- /dev/null
+++ b/source/blender/blenlib/BLI_vector_adaptor.hh
@@ -0,0 +1,105 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __BLI_VECTOR_ADAPTOR_HH__
+#define __BLI_VECTOR_ADAPTOR_HH__
+
+/** \file
+ * \ingroup bli
+ *
+ * A `blender::VectorAdaptor` is a container with a fixed maximum size and does not own the
+ * underlying memory. When an adaptor is constructed, you have to provide it with an uninitialized
+ * array that will be filled when elements are added to the vector. The vector adaptor is not able
+ * to grow. Therefore, it is undefined behavior to add more elements than fit into the provided
+ * buffer.
+ */
+
+#include "BLI_span.hh"
+
+namespace blender {
+
+template<typename T> class VectorAdaptor {
+ private:
+  T *begin_;
+  T *end_;
+  T *capacity_end_;
+
+ public:
+  VectorAdaptor() : begin_(nullptr), end_(nullptr), capacity_end_(nullptr)
+  {
+  }
+
+  VectorAdaptor(T *data, int64_t capacity, int64_t size = 0)
+      : begin_(data), end_(data + size), capacity_end_(data + capacity)
+  {
+  }
+
+  VectorAdaptor(MutableSpan<T> span) : VectorAdaptor(span.data(), span.size(), 0)
+  {
+  }
+
+  void append(const T &value)
+  {
+    BLI_assert(end_ < capacity_end_);
+    new (end_) T(value);
+    end_++;
+  }
+
+  void append(T &&value)
+  {
+    BLI_assert(end_ < capacity_end_);
+    new (end_) T(std::move(value));
+    end_++;
+  }
+
+  void append_n_times(const T &value, int64_t n)
+  {
+    BLI_assert(end_ + n <= capacity_end_);
+    uninitialized_fill_n(end_, n, value);
+    end_ += n;
+  }
+
+  void extend(Span<T> values)
+  {
+    BLI_assert(end_ + values.size() <= capacity_end_);
+    uninitialized_copy_n(values.data(), values.size(), end_);
+    end_ += values.size();
+  }
+
+  int64_t capacity() const
+  {
+    return capacity_end_ - begin_;
+  }
+
+  int64_t size() const
+  {
+    return end_ - begin_;
+  }
+
+  bool is_empty() const
+  {
+    return begin_ == end_;
+  }
+
+  bool is_full() const
+  {
+    return end_ == capacity_end_;
+  }
+};
+
+}  // namespace blender
+
+#endif /* __BLI_VECTOR_ADAPTOR_HH__ */
diff --git a/source/blender/blenlib/CMakeLists.txt b/source/blender/blenlib/CMakeLists.txt
index d7d1d701bc8..db44ebe8e55 100644
--- a/source/blender/blenlib/CMakeLists.txt
+++ b/source/blender/blenlib/CMakeLists.txt
@@ -267,6 +267,7 @@ set(SRC
   BLI_utility_mixins.hh
   BLI_uvproject.h
   BLI_vector.hh
+  BLI_vector_adaptor.hh
   BLI_vector_set.hh
   BLI_vector_set_slots.hh
   BLI_vfontdata.h