make PaintUniformColor return by reference (#5566)

Author: yuecideng

cpp/open3d/t/geometry/PointCloud.cpp

@@ -447,7 +447,7 @@ std::tuple<PointCloud, core::Tensor> PointCloud::RemoveDuplicatedPoints()
     return std::make_tuple(SelectByMask(masks), masks);
 }
 
-PointCloud PointCloud::PaintUniformColor(const core::Tensor &color) const {
+PointCloud &PointCloud::PaintUniformColor(const core::Tensor &color) {
     core::AssertTensorShape(color, {3});
     core::Tensor clipped_color = color.To(GetDevice());
     if (color.GetDtype() == core::Float32 ||
@@ -458,10 +458,9 @@ PointCloud PointCloud::PaintUniformColor(const core::Tensor &color) const {
             core::Tensor::Empty({GetPointPositions().GetLength(), 3},
                                 clipped_color.GetDtype(), GetDevice());
     pcd_colors.AsRvalue() = clipped_color;
-    PointCloud pcd(this->Clone());
-    pcd.SetPointColors(pcd_colors);
+    SetPointColors(pcd_colors);
 
-    return pcd;
+    return *this;
 }
 
 std::tuple<PointCloud, core::Tensor> PointCloud::ComputeBoundaryPoints(

cpp/open3d/t/geometry/PointCloud.h

@@ -318,6 +318,12 @@ class PointCloud : public Geometry, public DrawableGeometry {
     /// \return Rotated point cloud
     PointCloud &Rotate(const core::Tensor &R, const core::Tensor &center);
 
+    /// \brief Assigns uniform color to the point cloud.
+    ///
+    /// \param color  RGB color for the point cloud. {3,} shaped Tensor.
+    /// Floating color values are clipped between 0.0 and 1.0.
+    PointCloud &PaintUniformColor(const core::Tensor &color);
+
     /// \brief Select points from input pointcloud, based on boolean mask
     /// indices into output point cloud.
     ///
@@ -395,12 +401,6 @@ class PointCloud : public Geometry, public DrawableGeometry {
     std::tuple<PointCloud, core::Tensor> RemoveNonFinitePoints(
             bool remove_nan = true, bool remove_infinite = true) const;
 
-    /// \brief Assigns uniform color to the point cloud.
-    ///
-    /// \param color  RGB color for the point cloud. {3,} shaped Tensor.
-    /// Floating color values are clipped between 0.0 and 1.0.
-    PointCloud PaintUniformColor(const core::Tensor &color) const;
-
     /// \brief Returns the device attribute of this PointCloud.
     core::Device GetDevice() const override { return device_; }
 

cpp/tests/t/geometry/PointCloud.cpp

@@ -944,7 +944,7 @@ TEST_P(PointCloudPermuteDevices, HiddenPointRemoval) {
 TEST_P(PointCloudPermuteDevices, PaintUniformColor) {
     core::Device device = GetParam();
 
-    const t::geometry::PointCloud pcd_small(
+    t::geometry::PointCloud pcd_small(
             core::Tensor::Init<double>({{1.0, 1.0, 1.0},
                                         {1.1, 1.1, 1.1},
                                         {1.2, 1.2, 1.2},