Fix regression with camera sensors not using the background color set…

… in `<scene>` (#1515)

Signed-off-by: Addisu Z. Taddese <[email protected]>

src/rendering/RenderUtil.cc

@@ -213,7 +213,7 @@ class ignition::gazebo::RenderUtilPrivate
   /// \brief Scene background color. This is optional because a <scene> is
   /// always present, which has a default background color value. This
   /// backgroundColor variable is used to override the <scene> value.
-  public: std::optional<math::Color> backgroundColor = math::Color::Black;
+  public: std::optional<math::Color> backgroundColor;
 
   /// \brief Ambient color. This is optional because an <scene> is always
   /// present, which has a default ambient light value. This ambientLight

test/integration/CMakeLists.txt

@@ -79,6 +79,7 @@ endif()
 # Tests that require a valid display
 set(tests_needing_display
   camera_sensor_background.cc
+  camera_sensor_background_from_scene.cc
   camera_video_record_system.cc
   depth_camera.cc
   distortion_camera.cc

test/integration/camera_sensor_background_from_scene.cc

@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2022 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <gtest/gtest.h>
+
+#include <string>
+
+#include <ignition/transport/Node.hh>
+#include <ignition/utilities/ExtraTestMacros.hh>
+
+#include "ignition/gazebo/Server.hh"
+#include "ignition/gazebo/SystemLoader.hh"
+#include "ignition/gazebo/Util.hh"
+#include "ignition/gazebo/test_config.hh"
+
+#include "../helpers/EnvTestFixture.hh"
+
+using namespace ignition;
+using namespace std::chrono_literals;
+
+std::mutex mutex;
+int cbCount = 0;
+
+//////////////////////////////////////////////////
+/// Note: This test is almost identical to the test in
+/// camera_sensor_scene_background.cc, and the `cameraCb` could have been
+/// reused, but loading the world twice in a single processes causes errors with
+/// Ogre.
+class CameraSensorBackgroundFixture :
+  public InternalFixture<InternalFixture<::testing::Test>>
+{
+};
+
+/////////////////////////////////////////////////
+void cameraCb(const msgs::Image & _msg)
+{
+  ASSERT_EQ(msgs::PixelFormatType::RGB_INT8,
+      _msg.pixel_format_type());
+
+  for (unsigned int y = 0; y < _msg.height(); ++y)
+  {
+    for (unsigned int x = 0; x < _msg.width(); ++x)
+    {
+      // The "/test/worlds/camera_sensor_scene_background.sdf" world has set a
+      // background color of 1,0,0,1. So, all the pixels returned by the
+      // camera should be red.
+      unsigned char r = _msg.data()[y * _msg.step() + x*3];
+      ASSERT_EQ(255, static_cast<int>(r));
+
+      unsigned char g = _msg.data()[y * _msg.step() + x*3+1];
+      ASSERT_EQ(0, static_cast<int>(g));
+
+      unsigned char b = _msg.data()[y * _msg.step() + x*3+2];
+      ASSERT_EQ(0, static_cast<int>(b));
+    }
+  }
+  std::lock_guard<std::mutex> lock(mutex);
+  cbCount++;
+}
+
+/////////////////////////////////////////////////
+// Test sensors use the background color of <scene> by default
+TEST_F(CameraSensorBackgroundFixture,
+    IGN_UTILS_TEST_DISABLED_ON_MAC(RedBackgroundFromScene))
+{
+  const auto sdfFile = common::joinPaths(std::string(PROJECT_SOURCE_PATH),
+    "test", "worlds", "camera_sensor_scene_background.sdf");
+  // Start server
+  gazebo::ServerConfig serverConfig;
+  serverConfig.SetSdfFile(sdfFile);
+
+  gazebo::Server server(serverConfig);
+  EXPECT_FALSE(server.Running());
+  EXPECT_FALSE(*server.Running(0));
+
+  // subscribe to the camera topic
+  transport::Node node;
+  cbCount = 0;
+  node.Subscribe("/camera", &cameraCb);
+
+  // Run server and verify that we are receiving a message
+  // from the depth camera
+  server.Run(true, 100, false);
+
+  int i = 0;
+  while (i < 100 && cbCount <= 0)
+  {
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    i++;
+  }
+
+  std::lock_guard<std::mutex> lock(mutex);
+  EXPECT_GE(cbCount, 1);
+
+}

test/worlds/camera_sensor_scene_background.sdf

@@ -0,0 +1,58 @@
+<?xml version="1.0" ?>
+<sdf version="1.6">
+  <world name="sensors">
+    <physics name="1ms" type="ignored">
+      <max_step_size>.001</max_step_size>
+      <real_time_factor>0</real_time_factor>
+    </physics>
+    <plugin
+      filename="ignition-gazebo-physics-system"
+      name="ignition::gazebo::systems::Physics">
+    </plugin>
+    <plugin
+      filename="ignition-gazebo-sensors-system"
+      name="ignition::gazebo::systems::Sensors">
+      <render_engine>ogre2</render_engine>
+    </plugin>
+
+    <scene>
+      <background>1 0 0</background>
+    </scene>
+
+    <model name="camera">
+      <static>true</static>
+      <pose>0 0 1.0 0 0 0</pose>
+      <link name="link">
+        <collision name="collision">
+          <geometry>
+            <box>
+              <size>0.1 0.1 0.1</size>
+            </box>
+          </geometry>
+        </collision>
+        <visual name="visual">
+          <geometry>
+            <box>
+              <size>0.1 0.1 0.1</size>
+            </box>
+          </geometry>
+        </visual>
+        <sensor name="camera" type="camera">
+          <camera>
+            <horizontal_fov>1.047</horizontal_fov>
+            <image>
+              <width>320</width>
+              <height>240</height>
+            </image>
+            <clip>
+              <near>0.1</near>
+              <far>100</far>
+            </clip>
+          </camera>
+          <update_rate>30</update_rate>
+          <topic>camera</topic>
+        </sensor>
+      </link>
+    </model>
+  </world>
+</sdf>