[glass] Add glass: an application for display of robot data

This reuses many pieces of the current simulation GUI.  The common pieces have
been refactored into the libglass library.

The libglass library is designed to be usable for other standalone data
visualization applications (e.g. viewing data logs).

The name "glass" comes from "glass cockpit", as the application features
several multi-function displays that can be adjusted to display robot
information as needed.

simulation/halsim_gui/src/main/native/cpp/AccelerometerSimGui.cpp

@@ -0,0 +1,67 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019-2020 FIRST. All Rights Reserved.                        */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "AccelerometerSimGui.h"
+
+#include <glass/hardware/Accelerometer.h>
+#include <glass/other/DeviceTree.h>
+
+#include <memory>
+
+#include <hal/Value.h>
+#include <hal/simulation/AccelerometerData.h>
+
+#include "HALDataSource.h"
+#include "HALSimGui.h"
+#include "SimDeviceGui.h"
+
+using namespace glass;
+using namespace halsimgui;
+
+namespace {
+HALSIMGUI_DATASOURCE_DOUBLE_INDEXED(AccelerometerX, "X Accel");
+HALSIMGUI_DATASOURCE_DOUBLE_INDEXED(AccelerometerY, "Y Accel");
+HALSIMGUI_DATASOURCE_DOUBLE_INDEXED(AccelerometerZ, "Z Accel");
+
+class AccelerometerSimModel : public glass::AccelerometerModel {
+ public:
+  explicit AccelerometerSimModel(int32_t index)
+      : m_index{index}, m_xData{m_index}, m_yData{m_index}, m_zData{m_index} {}
+
+  void Update() override {}
+
+  bool Exists() override { return HALSIM_GetAccelerometerActive(m_index); }
+
+  glass::DataSource* GetXData() override { return &m_xData; }
+  glass::DataSource* GetYData() override { return &m_yData; }
+  glass::DataSource* GetZData() override { return &m_zData; }
+
+  int GetRange() override { return HALSIM_GetAccelerometerRange(m_index); }
+
+  void SetX(double val) override { HALSIM_SetAccelerometerX(m_index, val); }
+  void SetY(double val) override { HALSIM_SetAccelerometerY(m_index, val); }
+  void SetZ(double val) override { HALSIM_SetAccelerometerZ(m_index, val); }
+  void SetRange(int val) override {
+    HALSIM_SetAccelerometerRange(m_index,
+                                 static_cast<HAL_AccelerometerRange>(val));
+  }
+
+ private:
+  int32_t m_index;
+  AccelerometerXSource m_xData;
+  AccelerometerYSource m_yData;
+  AccelerometerZSource m_zData;
+};
+}  // namespace
+
+void AccelerometerSimGui::Initialize() {
+  SimDeviceGui::GetDeviceTree().Add(
+      std::make_unique<AccelerometerSimModel>(0), [](glass::Model* model) {
+        glass::DisplayAccelerometerDevice(
+            static_cast<AccelerometerSimModel*>(model));
+      });
+}