[viz] Use inlined byte array for heatmap png; remove VTK as dep (#307)

drake_ros/CMakeLists.txt

@@ -25,7 +25,6 @@ find_package(geometry_msgs REQUIRED)
 find_package(tf2_ros REQUIRED)
 find_package(tf2_eigen REQUIRED)
 find_package(visualization_msgs REQUIRED)
-find_package(VTK REQUIRED)
 
 add_subdirectory(core)
 add_subdirectory(tf2)
@@ -91,6 +90,5 @@ ament_export_dependencies(rosidl_typesupport_cpp)
 ament_export_dependencies(tf2_eigen)
 ament_export_dependencies(tf2_ros)
 ament_export_dependencies(visualization_msgs)
-ament_export_dependencies(VTK)
 
 ament_package()

drake_ros/package.xml

@@ -17,7 +17,6 @@
   <buildtool_depend>eigen3_cmake_module</buildtool_depend>
   <build_depend>eigen</build_depend>
 
-  <depend>libvtk9-dev</depend>
   <depend>rclcpp</depend>
   <depend>rclpy</depend>
   <depend>rosgraph_msgs</depend>

drake_ros/viz/BUILD.bazel

@@ -11,7 +11,6 @@ cc_library(
         "@ros2//:rclcpp_cc",
         "@ros2//:tf2_eigen_cc",
         "@ros2//:visualization_msgs_cc",
-        "@vtk//:vtkIOImage",
     ],
 )
 
@@ -22,6 +21,7 @@ cc_library(
         [
             "*.cc",
             "*.h",
+            "heatmap_png.inc",
         ],
     ),
     hdrs = glob(

drake_ros/viz/CMakeLists.txt

@@ -14,6 +14,7 @@ foreach(hdr ${HEADERS})
 endforeach()
 
 add_library(drake_ros_viz
+  heatmap_png.inc
   name_conventions.cc
   rviz_visualizer.cc
   scene_markers_system.cc
@@ -29,8 +30,6 @@ target_link_libraries(drake_ros_viz PUBLIC
     ${geometry_msgs_TARGETS}
     ${visualization_msgs_TARGETS}
 )
-target_link_libraries(drake_ros_viz PRIVATE
-  VTK::IOImage)
 
 target_include_directories(drake_ros_viz
   PUBLIC

drake_ros/viz/contact_markers_system.cc

@@ -30,11 +30,6 @@
 #include <tf2_eigen/tf2_eigen.hpp>
 #include <visualization_msgs/msg/marker.hpp>
 #include <visualization_msgs/msg/marker_array.hpp>
-#include <vtkImageData.h>
-#include <vtkNew.h>
-#include <vtkPNGWriter.h>
-#include <vtkSmartPointer.h>
-#include <vtkUnsignedCharArray.h>
 
 namespace drake_ros {
 namespace viz {
@@ -91,51 +86,10 @@ double calc_uv(double pressure, double min_pressure, double max_pressure) {
   return std::clamp(u, 0.0, 1.0);
 }
 
-void create_color(double value, double& red, double& green, double& blue) {
-  red = std::clamp(((value - 0.25) * 4.0), 0.0, 1.0);
-  green = std::clamp(((value - 0.5) * 4.0), 0.0, 1.0);
-  if (value < 0.25) {
-    blue = std::clamp(value * 4.0, 0.0, 1.0);
-  } else if (value > 0.75) {
-    blue = std::clamp((value - 0.75) * 4.0, 0.0, 1.0);
-  } else {
-    blue = std::clamp(1.0 - (value - 0.25) * 4.0, 0.0, 1.0);
-  }
-}
-
 std::vector<uint8_t> GenerateHeatmapPng() {
-  // Make a heatmap texture
-  size_t kWidth = 1024;
-  size_t kHeight = 1;
-  size_t kNumChannels = 4;
-  vtkNew<vtkImageData> vtk_image;
-  vtk_image->SetDimensions(kWidth, kHeight, 1);
-  vtk_image->AllocateScalars(VTK_UNSIGNED_CHAR, kNumChannels);
-
-  auto image_ptr =
-      reinterpret_cast<unsigned char*>(vtk_image->GetScalarPointer());
-  double red, green, blue;
-  for (size_t w = 0; w < kWidth; ++w) {
-    const size_t offset = w * kNumChannels;
-    create_color(static_cast<double>(w) / kWidth, red, green, blue);
-    image_ptr[offset + 0] = static_cast<unsigned char>(red * 255.0);
-    image_ptr[offset + 1] = static_cast<unsigned char>(green * 255.0);
-    image_ptr[offset + 2] = static_cast<unsigned char>(blue * 255.0);
-    image_ptr[offset + 3] = 255;
-  }
-
-  auto image_writer = vtkSmartPointer<vtkPNGWriter>::New();
-  image_writer->SetWriteToMemory(true);
-  image_writer->SetInputData(vtk_image.GetPointer());
-  image_writer->Write();
-  auto vtk_results = image_writer->GetResult();
-  auto data_itr = vtk_results->Begin();
-  std::vector<uint8_t> texture;
-  while (data_itr != vtk_results->End()) {
-    texture.push_back(*data_itr);
-    ++data_itr;
-  }
-  return texture;
+  return
+#include "./heatmap_png.inc"
+      ;
 }
 
 }  // namespace

drake_ros/viz/heatmap_png.inc

@@ -0,0 +1,9 @@
+// AUTOGENERATED, DO NOT EDIT
+{
+  137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13, 73, 72, 68, 82, 0, 0, 4, 0, 0,
+      0, 0, 1, 8, 2, 0, 0, 0, 207, 108, 75, 98, 0, 0, 0, 44, 73, 68, 65, 84,
+      120, 156, 237, 212, 193, 13, 0, 48, 12, 194, 64, 188, 255, 208, 205, 167,
+      91, 216, 209, 45, 0, 72, 97, 255, 72, 148, 198, 158, 150, 60, 126, 232,
+      247, 155, 181, 62, 85, 16, 175, 3, 112, 247, 1, 14, 225, 11, 252, 43, 0,
+      0, 0, 0, 73, 69, 78, 68, 174, 66, 96, 130,
+}

drake_ros/viz/heatmap_png_generate.py

@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+"""
+PNG encoding of a heatmap for hydroelastic.
+
+Requires Python, PIL, and NumPy.
+"""
+
+import io
+import os
+
+import numpy as np
+from PIL import Image
+
+
+def main():
+    h = 1
+    w = 1024
+    c = 3
+    array = np.zeros((h, w, c), dtype=np.uint8)
+    values = np.linspace(0, 1, w)
+
+    red = np.clip((values - 0.25) * 4.0, 0.0, 1.0)
+    green = np.clip((values - 0.5) * 4.0, 0.0, 1.0)
+    blue = np.clip(1.0 - (values - 0.25) * 4.0, 0.0, 1.0)
+    mask = values < 0.25
+    blue[mask] = np.clip(values[mask] * 4.0, 0.0, 1.0)
+    mask = values > 0.75
+    blue[mask] = np.clip((values[mask] - 0.75) * 4.0, 0.0, 1.0)
+    mask = values > 0.75
+
+    array[0, :, 0] = red * 255.0
+    array[0, :, 1] = green * 255.0
+    array[0, :, 2] = blue * 255.0
+
+    image = Image.fromarray(array)
+    stream = io.BytesIO()
+    image.save(stream, format='png')
+    raw = stream.getvalue()
+
+    out = "// AUTOGENERATED, DO NOT EDIT\n"
+    out += "{\n"
+    for byte in raw:
+        out += str(int(byte)) + ", "
+    out += "\n}\n"
+
+    os.chdir(os.path.dirname(__file__))
+    with open("heatmap_png.inc", "w") as f:
+        f.write(out)
+
+    print("This may need to get reformatted by ament_clang_format")
+
+
+if __name__ == "__main__":
+    main()