text: // https://github.com/CedricGuillemet/ImGuizmo
  // v 1.04 WIP
  //
  // The MIT License(MIT)
  // 
  // Copyright(c) 2016 Cedric Guillemet
  // 
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files(the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions :
  // 
  // The above copyright notice and this permission notice shall be included in all
  // copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  // SOFTWARE.
  //
  // -------------------------------------------------------------------------------------------
  // History : 
  // 2016/09/11 Behind camera culling. Scaling Delta matrix not multiplied by source matrix scales. local/world rotation and translation fixed. Display message is incorrect (X: ... Y:...) in local mode.
  // 2016/09/09 Hatched negative axis. Snapping. Documentation update.
  // 2016/09/04 Axis switch and translation plan autohiding. Scale transform stability improved
  // 2016/09/01 Mogwai changed to Manipulate. Draw debug cube. Fixed inverted scale. Mixing scale and translation/rotation gives bad results.
  // 2016/08/31 First version
  //
  // -------------------------------------------------------------------------------------------
  // Future (no order):
  //
  // - Multi view
  // - display rotation/translation/scale infos in local/world space and not only local
  // - finish local/world matrix application
  // - OPERATION as bitmask
  // 
  // -------------------------------------------------------------------------------------------
  // Example 
  #if 0
  void EditTransform(const Camera& camera, matrix_t& matrix)
  {
  	static ImGuizmo::OPERATION mCurrentGizmoOperation(ImGuizmo::ROTATE);
  	static ImGuizmo::MODE mCurrentGizmoMode(ImGuizmo::WORLD);
  	if (ImGui::IsKeyPressed(90))
  		mCurrentGizmoOperation = ImGuizmo::TRANSLATE;
  	if (ImGui::IsKeyPressed(69))
  		mCurrentGizmoOperation = ImGuizmo::ROTATE;
  	if (ImGui::IsKeyPressed(82)) // r Key
  		mCurrentGizmoOperation = ImGuizmo::SCALE;
  	if (ImGui::RadioButton("Translate", mCurrentGizmoOperation == ImGuizmo::TRANSLATE))
  		mCurrentGizmoOperation = ImGuizmo::TRANSLATE;
  	ImGui::SameLine();
  	if (ImGui::RadioButton("Rotate", mCurrentGizmoOperation == ImGuizmo::ROTATE))
  		mCurrentGizmoOperation = ImGuizmo::ROTATE;
  	ImGui::SameLine();
  	if (ImGui::RadioButton("Scale", mCurrentGizmoOperation == ImGuizmo::SCALE))
  		mCurrentGizmoOperation = ImGuizmo::SCALE;
  	float matrixTranslation[3], matrixRotation[3], matrixScale[3];
  	ImGuizmo::DecomposeMatrixToComponents(matrix.m16, matrixTranslation, matrixRotation, matrixScale);
  	ImGui::InputFloat3("Tr", matrixTranslation, 3);
  	ImGui::InputFloat3("Rt", matrixRotation, 3);
  	ImGui::InputFloat3("Sc", matrixScale, 3);
  	ImGuizmo::RecomposeMatrixFromComponents(matrixTranslation, matrixRotation, matrixScale, matrix.m16);
  	if (mCurrentGizmoOperation != ImGuizmo::SCALE)
  	{
  		if (ImGui::RadioButton("Local", mCurrentGizmoMode == ImGuizmo::LOCAL))
  			mCurrentGizmoMode = ImGuizmo::LOCAL;
  		ImGui::SameLine();
  		if (ImGui::RadioButton("World", mCurrentGizmoMode == ImGuizmo::WORLD))
  			mCurrentGizmoMode = ImGuizmo::WORLD;
  	}
  	static bool useSnap(false);
  	if (ImGui::IsKeyPressed(83))
  		useSnap = !useSnap;
  	ImGui::Checkbox("", &useSnap);
  	ImGui::SameLine();
  	vec_t snap;
  	switch (mCurrentGizmoOperation)
  	{
  	case ImGuizmo::TRANSLATE:
  		snap = config.mSnapTranslation;
  		ImGui::InputFloat3("Snap", &snap.x);
  		break;
  	case ImGuizmo::ROTATE:
  		snap = config.mSnapRotation;
  		ImGui::InputFloat("Angle Snap", &snap.x);
  		break;
  	case ImGuizmo::SCALE:
  		snap = config.mSnapScale;
  		ImGui::InputFloat("Scale Snap", &snap.x);
  		break;
  	}
  	ImGuiIO& io = ImGui::GetIO();
  	ImGuizmo::SetRect(0, 0, io.DisplaySize.x, io.DisplaySize.y);
  	ImGuizmo::Manipulate(camera.mView.m16, camera.mProjection.m16, mCurrentGizmoOperation, mCurrentGizmoMode, matrix.m16, NULL, useSnap ? &snap.x : NULL);
  }
  #endif
  #pragma once
  
  #ifdef USE_IMGUI_API
  #include "imconfig.h"
  #endif
  #ifndef IMGUI_API
  #define IMGUI_API
  #endif
  
  namespace ImGuizmo
  {
  	// call BeginFrame right after ImGui_XXXX_NewFrame();
  	IMGUI_API void BeginFrame();
  
  	// call EndFrame when ImGuizmo renderings is over
  	IMGUI_API void EndFrame();
  
  	// return true if mouse cursor is over any gizmo control (axis, plan or screen component)
  	IMGUI_API bool IsOver();
  
  	// return true if mouse IsOver or if the gizmo is in moving state
  	IMGUI_API bool IsUsing();
  
  	// enable/disable the gizmo. Stay in the state until next call to Enable.
  	// gizmo is rendered with gray half transparent color when disabled
  	IMGUI_API void Enable(bool enable);
  
  	// helper functions for manualy editing translation/rotation/scale with an input float
  	// translation, rotation and scale float points to 3 floats each
  	// Angles are in degrees (more suitable for human editing)
  	// example:
  	// float matrixTranslation[3], matrixRotation[3], matrixScale[3];
  	// ImGuizmo::DecomposeMatrixToComponents(gizmoMatrix.m16, matrixTranslation, matrixRotation, matrixScale);
  	// ImGui::InputFloat3("Tr", matrixTranslation, 3);
  	// ImGui::InputFloat3("Rt", matrixRotation, 3);
  	// ImGui::InputFloat3("Sc", matrixScale, 3);
  	// ImGuizmo::RecomposeMatrixFromComponents(matrixTranslation, matrixRotation, matrixScale, gizmoMatrix.m16);
  	//
  	// These functions have some numerical stability issues for now. Use with caution.
  	IMGUI_API void DecomposeMatrixToComponents(const float *matrix, float *translation, float *rotation, float *scale);
  	IMGUI_API void RecomposeMatrixFromComponents(const float *translation, const float *rotation, const float *scale, float *matrix);
  
  	IMGUI_API void SetRect(float x, float y, float width, float height);
  
  	// Render a cube with face color corresponding to face normal. Usefull for debug/tests
  	IMGUI_API void DrawCube(const float *view, const float *projection, float *matrix);
  
  	// call it when you want a gizmo
  	// Needs view and projection matrices. 
  	// matrix parameter is the source matrix (where will be gizmo be drawn) and might be transformed by the function. Return deltaMatrix is optional
  	// translation is applied in world space
  	enum OPERATION
  	{
  		TRANSLATE,
  		ROTATE,
  		SCALE
  	};
  
  	enum MODE
  	{
  		LOCAL,
  		WORLD
  	};
  
  	IMGUI_API void Manipulate(const float *view, const float *projection, OPERATION operation, MODE mode, float *matrix, float *deltaMatrix = 0, float *snap = 0, float *localBounds = 0, float *boundsSnap = 0);
  };
  