Actually managed to add SDL2 support somehow

src/dawnsdl2/input/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Copyright (c) 2022 Dominic Masters
+# 
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+# Sources
+target_sources(${DAWN_TARGET_NAME}
+  PRIVATE
+    InputManager.cpp
+)

src/dawnsdl2/input/InputManager.cpp

@@ -0,0 +1,20 @@
+// Copyright (c) 2022 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#include "InputManager.hpp"
+#include "game/DawnGame.hpp"
+
+using namespace Dawn;
+
+InputManager::InputManager(DawnGame *game) : IInputManager<int32_t>(game) {
+
+}
+
+float_t InputManager::getInputValue(int32_t axis) {
+  auto exist = this->rawInputValues.find(axis);
+  if(exist == this->rawInputValues.end()) return 0.0f;
+  
+  return exist->second;
+}

src/dawnsdl2/input/InputManager.hpp

@@ -0,0 +1,19 @@
+// Copyright (c) 2022 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include "input/_InputManager.hpp"
+
+namespace Dawn {
+  class InputManager : public IInputManager<int32_t> {
+    protected:
+      float_t getInputValue(int32_t axis) override;
+
+    public:
+      std::map<int32_t, float_t> rawInputValues;
+
+      InputManager(DawnGame *game);
+  };
+}