[glass] Add more widgets (#2947)

This adds the following widgets:
- Speed Controller
- Gyroscope
- Command
- Subsystem
- PIDController
- Scheduler

glass/src/lib/native/cpp/other/PIDController.cpp

@@ -0,0 +1,54 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 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 "glass/other/PIDController.h"
+
+#include <string>
+
+#include <imgui.h>
+
+#include "glass/Context.h"
+#include "glass/DataSource.h"
+
+using namespace glass;
+
+void glass::DisplayPIDController(PIDControllerModel* m) {
+  if (auto name = m->GetName()) {
+    ImGui::Text("%s", name);
+    ImGui::Separator();
+  }
+
+  if (m->Exists()) {
+    auto createTuningParameter = [](const char* name, double* v,
+                                    std::function<void(double)> callback) {
+      ImGui::SetNextItemWidth(ImGui::GetFontSize() * 4);
+      if (ImGui::InputDouble(name, v, 0.0, 0.0, "%.3f")) callback(*v);
+    };
+
+    if (auto p = m->GetPData()) {
+      double value = p->GetValue();
+      createTuningParameter("P", &value, [=](auto v) { m->SetP(v); });
+    }
+    if (auto i = m->GetIData()) {
+      double value = i->GetValue();
+      createTuningParameter("I", &value, [=](auto v) { m->SetI(v); });
+    }
+    if (auto d = m->GetDData()) {
+      double value = d->GetValue();
+      createTuningParameter("D", &value, [=](auto v) { m->SetD(v); });
+    }
+    if (auto s = m->GetSetpointData()) {
+      double value = s->GetValue();
+      createTuningParameter("Setpoint", &value,
+                            [=](auto v) { m->SetSetpoint(v); });
+    }
+  } else {
+    ImGui::PushStyleColor(ImGuiCol_Text, IM_COL32(96, 96, 96, 255));
+    ImGui::Text("Unknown PID Controller");
+    ImGui::PopStyleColor();
+  }
+}