From fe4e646405eb3a8e38617411a2f9b1b8f6b8a8cb Mon Sep 17 00:00:00 2001
From: Hans Goudey <h.goudey@me.com>
Date: Wed, 8 Jun 2022 18:40:08 +0200
Subject: Fix: Incorrect curves and pointcloud bounding boxes

The generic bounds utility used an incorrect initial value. The value
cannot be zero-initialized, because that breaks the case where all
values are greater than zero.
---
 source/blender/blenlib/BLI_bounds.hh            | 6 ++++--
 source/blender/blenlib/tests/BLI_bounds_test.cc | 7 +++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

(limited to 'source')

diff --git a/source/blender/blenlib/BLI_bounds.hh b/source/blender/blenlib/BLI_bounds.hh
index d20382ed500..f5a18a0ea48 100644
--- a/source/blender/blenlib/BLI_bounds.hh
+++ b/source/blender/blenlib/BLI_bounds.hh
@@ -28,10 +28,11 @@ template<typename T> static std::optional<MinMaxResult<T>> min_max(Span<T> value
   if (values.is_empty()) {
     return std::nullopt;
   }
+  const MinMaxResult<T> init{values.first(), values.first()};
   return threading::parallel_reduce(
       values.index_range(),
       1024,
-      MinMaxResult<T>(),
+      init,
       [&](IndexRange range, const MinMaxResult<T> &init) {
         MinMaxResult<T> result = init;
         for (const int i : range) {
@@ -55,10 +56,11 @@ static std::optional<MinMaxResult<T>> min_max_with_radii(Span<T> values, Span<Ra
   if (values.is_empty()) {
     return std::nullopt;
   }
+  const MinMaxResult<T> init{values.first(), values.first()};
   return threading::parallel_reduce(
       values.index_range(),
       1024,
-      MinMaxResult<T>(),
+      init,
       [&](IndexRange range, const MinMaxResult<T> &init) {
         MinMaxResult<T> result = init;
         for (const int i : range) {
diff --git a/source/blender/blenlib/tests/BLI_bounds_test.cc b/source/blender/blenlib/tests/BLI_bounds_test.cc
index 9c123d4705c..5aa4e710e90 100644
--- a/source/blender/blenlib/tests/BLI_bounds_test.cc
+++ b/source/blender/blenlib/tests/BLI_bounds_test.cc
@@ -33,6 +33,13 @@ TEST(bounds, MinMaxFloat)
   EXPECT_EQ(result->max, 3.0f);
 }
 
+TEST(bounds, MinGreaterThanZero)
+{
+  Array<float> data = {1.5f, 3.0f, 1.1f, 100.0f};
+  auto result = bounds::min_max(data.as_span());
+  EXPECT_GT(result->min, 1.0f);
+}
+
 TEST(bounds, MinMaxRadii)
 {
   Array<int2> data = {int2(0, 1), int2(3, -1), int2(0, -2), int2(-1, 1)};
-- 
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