No colors in VisualLiDARVisualizer

[themightyoarfish]

Describe the bug

Regardless of the blend weight used, the visualized point cloud is black

To Reproduce
Steps to reproduce the behavior:

1. Create a dataset with 1 image and 1 cloud
2. Create pinhole camera model with some params
3. Create visualizer with this dataset
4. Change blend weight slider around

Expected behavior
Cloud points are colorized according to their intensity

Screenshots and sample data

Environment:

• OS: Macos Sequioa 15.5
• ROS version: n/a, not using ROS

Additional context:

I see the message

UNSUPPORTED (log once): POSSIBLE ISSUE: unit 0 GLD_TEXTURE_INDEX_2D is unloadable and bound to sampler type (Float) - using zero texture because texture unloadable

When the program starts, but i don't know if this means anything.

[themightyoarfish]

Ok the explanation seems to be that the coloring uses the current camera-lidar transfrom. in src/vlcal/common/points_color_updater.cpp, the color update() function skips points that do not map into the image, so one will only get colors once there is a rough transformation. This seems unreasonable, as i am using the manual initial guess class to create just this, and it would be much easier if the intensity structure could be seen.

[themightyoarfish]

I can do something like this to get intensity coloring:

diff --git a/src/vlcal/common/points_color_updater.cpp b/src/vlcal/common/points_color_updater.cpp
index 2c220ac..3b91bcf 100644
--- a/src/vlcal/common/points_color_updater.cpp
+++ b/src/vlcal/common/points_color_updater.cpp
@@ -39,20 +39,25 @@ void PointsColorUpdater::update(const Eigen::Isometry3d& T_camera_liar, const do

   for (int i = 0; i < points->size(); i++) {
     const Eigen::Vector4d pt_camera = T_camera_liar * points->points[i];
-
+    bool in_image = true;
     if (pt_camera.head<3>().normalized().z() < min_nz) {
       // Out of FoV
-      continue;
+      // continue;
+      in_image = false;
     }

     const Eigen::Vector2i pt_2d = proj->project(pt_camera.head<3>()).cast<int>();
     if ((pt_2d.array() < Eigen::Array2i::Zero()).any() || (pt_2d.array() >= Eigen::Array2i(image.cols, image.rows)).any()) {
       // Out of Image
-      continue;
+      // continue;
+      in_image = false;
     }

-    const unsigned char pix = image.at<std::uint8_t>(pt_2d.y(), pt_2d.x());
-    const Eigen::Vector4f color(pix / 255.0f, pix / 255.0f, pix / 255.0f, 1.0f);
+    Eigen::Vector4f color(0, 0, 0, 1);
+    if (in_image) {
+      const auto pix = image.at<std::uint8_t>(pt_2d.y(), pt_2d.x());
+      color = Eigen::Vector4f(pix / 255.0f, pix / 255.0f, pix / 255.0f, 1.0f);
+    }

     colors->at(i) = color * blend_weight + intensity_colors[i] * (1.0 - blend_weight);
   }