OpenEngine/editor/include/editor.hpp

#ifndef EDITOR_HPP
#define EDITOR_HPP

#include "open_engine/input/input_system.hpp"
#include <view_layer.hpp>
#include <open_engine.hpp>

#include <glm/ext/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/matrix.hpp>
#include <glm/fwd.hpp>
#include <imgui.h>
#include <glad/glad.h>
#include <GLFW/glfw3.h>

class EditorLayer : public OpenEngine::Layer
{
    public:
        EditorLayer(OpenEngine::Ref<ViewLayer>& view_layer)
            : OpenEngine::Layer("editor_layer"),
            view(view_layer)
        {
        }
        ~EditorLayer() {};

        void OnAttach() override
        {
            OE_PROFILE_FUNCTION();
        }

        void OnDetach() override
        {
        }

        void OnUpdate() override
        {

            OpenEngine::Renderer2D::ResetStats();
            {
                OE_PROFILE_FUNCTION();

                view->GetCamera().OnUpdate();
            }

            OpenEngine::Renderer2D::EndScene();
        }

        void OnEvent(OpenEngine::Event& event) override
        {
            OE_PROFILE_FUNCTION();

            {
                OE_PROFILE_SCOPE("Camera OnEvent");
                view->GetCamera().OnEvent(event);
            }
        }

        float remap(float value, float minInput, float maxInput, float minOutput, float maxOutput) {
            // 1. Normalize the input to a 0.0 - 1.0 range
            float t = (value - minInput) / (maxInput - minInput);

            // 2. Use glm::mix to interpolate between the output range
            return glm::mix(minOutput, maxOutput, t);
        }

        glm::vec3 ScreenToWorld(
                float screenX, 
                float screenY, 
                float screenZ,  // depth value (0.0 = near plane, 1.0 = far plane)
                const glm::mat4& view, 
                const glm::mat4& projection,
                int viewportWidth,
                int viewportHeight)
        {
            // 1. Convert screen coordinates to normalized device coordinates (NDC)
            // Screen space: origin at top-left, Y points down
            // NDC space: origin at center, range [-1, 1] for x and y

            float x = (2.0f * screenX) / viewportWidth - 1.0f;
            float y = 1.0f - (2.0f * screenY) / viewportHeight;  // Flip Y
            float z = 2.0f * screenZ - 1.0f;  // [0,1] -> [-1,1]

            glm::vec4 clipCoords(x, y, z, 1.0f);

            // 2. Transform from clip space to view space
            glm::mat4 invProjection = glm::inverse(projection);
            glm::vec4 viewCoords = invProjection * clipCoords;

            // 3. Transform from view space to world space
            glm::mat4 invView = glm::inverse(view);
            glm::vec4 worldCoords = invView * viewCoords;

            // 4. Perspective divide
            if (worldCoords.w != 0.0f) {
                worldCoords /= worldCoords.w;
            }

            return glm::vec3(worldCoords);
        }

        void OnImGuiRender() override
        {
            OE_PROFILE_FUNCTION();

            OpenEngine::Ref<OpenEngine::FrameBuffer> framebuffer = view->GetFramebuffer();

            ImGui::DockSpaceOverViewport();

            ImGui::Begin("Square settings");

            //ImGui::SliderFloat("Angle", &angle, -360, 360);
            //ImGui::ColorPicker4("Rectangle color", &rectangle_color[0]);

            for (auto& result : profiling_results)
            {
                char label[50];
                strcpy(label, "%.3fms ");
                strcat(label, result.name);
                ImGui::Text(label, result.duration);
            }

            profiling_results.clear();

            ImGui::End();
            ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2{ 0, 0 });
            ImGui::Begin("Viewport");
            ImVec2 viewport_panel_size = ImGui::GetContentRegionAvail();
            if (viewport_size != *((glm::vec2*)&viewport_panel_size)) {
                framebuffer->Resize(viewport_panel_size.x, viewport_panel_size.y);
                viewport_size = { viewport_panel_size.x, viewport_panel_size.y };

                view->GetCamera().OnResize(viewport_panel_size.x, viewport_panel_size.y);
            }
            uint32_t texture_id = framebuffer->GetColorAttachmentRendererID();
            ImGuiTabBarFlags tab_bar_flags = ImGuiTabBarFlags_None;
            if (ImGui::BeginTabBar("MyTabBar", tab_bar_flags))
            {
                if (ImGui::BeginTabItem("Avocado"))
                {
                    ImVec2 imgui_cursor_position = ImGui::GetCursorScreenPos();

                    auto pair_position = OpenEngine::Input::GetMousePosition();
                    glm::vec2 mouse_position = { pair_position.first, pair_position.second };

                    int max_x = viewport_size.x + imgui_cursor_position.x;
                    int max_y = viewport_size.y + imgui_cursor_position.y;

                    if ((mouse_position.x <= max_x && mouse_position.x >= imgui_cursor_position.x)
                            && (mouse_position.y <= max_y && mouse_position.y >= imgui_cursor_position.y)) {

                        float x = mouse_position.x - imgui_cursor_position.x;
                        float y = mouse_position.y - imgui_cursor_position.y;

                        auto& camera = view->GetCamera().GetCamera();
                        auto world_coords = ScreenToWorld(x, y, 0.0f,
                                camera.GetViewMatrix(),
                                camera.GetProjectionMatrix(),
                                viewport_size.x,
                                viewport_size.y);
                        view->SetCursorPos({ world_coords.x, world_coords.y });
                    }
                    ImGui::Image((void*)texture_id, ImVec2{ viewport_size.x, viewport_size.y }, ImVec2{ 0, 1 }, ImVec2{ 1, 0 });
                    ImGui::EndTabItem();
                }
                if (ImGui::BeginTabItem("Broccoli"))
                {
                    ImGui::Text("This is the Broccoli tab!\nblah blah blah blah blah");
                    ImGui::EndTabItem();
                }
                if (ImGui::BeginTabItem("Cucumber"))
                {
                    ImGui::Text("This is the Cucumber tab!\nblah blah blah blah blah");
                    ImGui::EndTabItem();
                }
                ImGui::EndTabBar();
            }
            ImGui::End();
            ImGui::PopStyleVar();

            auto stats = OpenEngine::Renderer2D::GetStats();
            static float time = 0;

            time += OpenEngine::Time::DeltaTime();

            if (time >= 1) {
                time = 0;
            }

            ImGui::Begin("Statistics");
            ImGui::Text("FPS: %0.0f", 1 / OpenEngine::Time::DeltaTime());
            ImGui::Text("Renderer2D:");
            ImGui::Text("\t\tDraw calls: %d", stats.draw_calls);
            ImGui::Text("\t\tQuad count: %d", stats.quad_count);
            ImGui::Text("\t\tVertices count: %d", stats.GetToralVertexCount());
            ImGui::Text("\t\tIndices count: %d", stats.GetToralIndexCount());
            ImGui::ShowDemoWindow();
            ImGui::End();
        }

    private:
        std::vector<OpenEngine::Time::ProfilingResult> profiling_results;

        glm::vec2 viewport_size = { 0.0f, 0.0f };

        OpenEngine::Ref<ViewLayer> view;
};

class EditorApp : public OpenEngine::Application
{
    public:
        EditorApp();
        ~EditorApp();
};

#endif // EDITOR_HPP