XCEngine/editor/src/panels/SceneViewPanel.cpp

#include "Actions/ActionRouting.h"
#include "Core/IEditorContext.h"
#include "Core/ISceneManager.h"
#include "Core/ISelectionManager.h"
#include "SceneViewPanel.h"
#include "Viewport/SceneViewportEditorOverlayData.h"
#include "Viewport/SceneViewportHudOverlay.h"
#include "Viewport/SceneViewportInteractionActions.h"
#include "Viewport/SceneViewportInteractionResolver.h"
#include "Viewport/SceneViewportMath.h"
#include "Viewport/SceneViewportTransformGizmoCoordinator.h"
#include "ViewportPanelContent.h"
#include "Platform/Win32Utf8.h"
#include "UI/UI.h"

#include <imgui.h>

#include <algorithm>
#include <filesystem>
#include <vector>

namespace XCEngine {
namespace Editor {

namespace {

struct SceneViewportToolOverlayResult {
    bool hovered = false;
    bool clicked = false;
    SceneViewportToolMode clickedTool = SceneViewportToolMode::Move;
};

const char* GetSceneViewportPivotModeLabel(SceneViewportPivotMode mode) {
    return mode == SceneViewportPivotMode::Pivot ? "Pivot" : "Center";
}

const char* GetSceneViewportTransformSpaceModeLabel(SceneViewportTransformSpaceMode mode) {
    return mode == SceneViewportTransformSpaceMode::Global ? "Global" : "Local";
}

float GetSceneToolbarToggleWidth(const char* firstLabel, const char* secondLabel) {
    constexpr float kHorizontalPadding = 10.0f;
    constexpr float kMinWidth = 68.0f;
    const float maxLabelWidth = (std::max)(
        ImGui::CalcTextSize(firstLabel).x,
        ImGui::CalcTextSize(secondLabel).x);
    return (std::max)(kMinWidth, maxLabelWidth + kHorizontalPadding * 2.0f);
}

void RenderSceneViewportTopBar(
    SceneViewportPivotMode& pivotMode,
    SceneViewportTransformSpaceMode& transformSpaceMode) {
    constexpr float kSceneToolbarHeight = 24.0f;
    constexpr float kSceneToolbarPaddingY = 0.0f;
    constexpr float kSceneToolbarButtonHeight = kSceneToolbarHeight - kSceneToolbarPaddingY * 2.0f;
    constexpr ImVec2 kSceneToolbarButtonFramePadding(8.0f, 1.0f);

    UI::PanelToolbarScope toolbar(
        "SceneToolbar",
        kSceneToolbarHeight,
        ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse,
        true,
        ImVec2(UI::ToolbarPadding().x, kSceneToolbarPaddingY),
        ImVec2(0.0f, UI::ToolbarItemSpacing().y),
        ImVec4(0.23f, 0.23f, 0.23f, 1.0f));
    if (!toolbar.IsOpen()) {
        return;
    }

    ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, kSceneToolbarButtonFramePadding);
    ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, 0.0f);

    if (UI::ToolbarButton(
            GetSceneViewportPivotModeLabel(pivotMode),
            true,
            ImVec2(GetSceneToolbarToggleWidth("Pivot", "Center"), kSceneToolbarButtonHeight))) {
        pivotMode = pivotMode == SceneViewportPivotMode::Pivot
            ? SceneViewportPivotMode::Center
            : SceneViewportPivotMode::Pivot;
    }

    ImGui::SameLine(0.0f, 0.0f);

    if (UI::ToolbarButton(
            GetSceneViewportTransformSpaceModeLabel(transformSpaceMode),
            true,
            ImVec2(GetSceneToolbarToggleWidth("Global", "Local"), kSceneToolbarButtonHeight))) {
        transformSpaceMode = transformSpaceMode == SceneViewportTransformSpaceMode::Global
            ? SceneViewportTransformSpaceMode::Local
            : SceneViewportTransformSpaceMode::Global;
    }

    ImGui::PopStyleVar(2);
}

const char* GetSceneViewportToolTooltip(SceneViewportToolMode toolMode) {
    switch (toolMode) {
    case SceneViewportToolMode::ViewMove:
        return "View Move";
    case SceneViewportToolMode::Move:
        return "Move";
    case SceneViewportToolMode::Rotate:
        return "Rotate";
    case SceneViewportToolMode::Scale:
        return "Scale";
    case SceneViewportToolMode::Transform:
        return "Transform";
    default:
        return "";
    }
}

const char* GetSceneViewportToolIconBaseName(SceneViewportToolMode toolMode) {
    switch (toolMode) {
    case SceneViewportToolMode::ViewMove:
        return "view_move_tool";
    case SceneViewportToolMode::Move:
        return "move_tool";
    case SceneViewportToolMode::Rotate:
        return "rotate_tool";
    case SceneViewportToolMode::Scale:
        return "scale_tool";
    case SceneViewportToolMode::Transform:
        return "transform_tool";
    default:
        return "";
    }
}

std::string BuildSceneViewportIconPath(const char* iconBaseName, bool active = false) {
    const std::filesystem::path exeDir(
        XCEngine::Editor::Platform::Utf8ToWide(XCEngine::Editor::Platform::GetExecutableDirectoryUtf8()));
    std::filesystem::path iconPath =
        exeDir / L".." / L".." / L"resources" / L"Icons" /
        std::filesystem::path(XCEngine::Editor::Platform::Utf8ToWide(iconBaseName));
    if (active) {
        iconPath += L"_on";
    }
    iconPath += L".png";
    return XCEngine::Editor::Platform::WideToUtf8(iconPath.lexically_normal().wstring());
}

const std::string& GetSceneViewportToolIconPath(SceneViewportToolMode toolMode, bool active) {
    static std::string cachedPaths[5][2] = {};
    const size_t toolIndex = static_cast<size_t>(toolMode);
    const size_t stateIndex = active ? 1u : 0u;
    std::string& cachedPath = cachedPaths[toolIndex][stateIndex];
    if (!cachedPath.empty()) {
        return cachedPath;
    }

    cachedPath = BuildSceneViewportIconPath(GetSceneViewportToolIconBaseName(toolMode), active);
    return cachedPath;
}

SceneViewportToolOverlayResult RenderSceneViewportToolOverlay(
    const ViewportPanelContentResult& content,
    SceneViewportToolMode activeTool) {
    SceneViewportToolOverlayResult result = {};
    if (!content.hasViewportArea) {
        return result;
    }

    constexpr float kButtonExtent = 30.0f;
    constexpr float kButtonSpacing = 6.0f;
    constexpr float kPanelPadding = 6.0f;
    constexpr float kViewportInset = 10.0f;
    constexpr float kIconInset = 4.0f;
    constexpr size_t kToolCount = 5;

    ImDrawList* drawList = ImGui::GetWindowDrawList();
    if (drawList == nullptr) {
        return result;
    }

    const ImVec2 panelMin(
        content.itemMin.x + kViewportInset,
        content.itemMin.y + kViewportInset);
    const ImVec2 panelMax(
        panelMin.x + kPanelPadding * 2.0f + kButtonExtent,
        panelMin.y + kPanelPadding * 2.0f + kToolCount * kButtonExtent + (kToolCount - 1) * kButtonSpacing);
    drawList->AddRectFilled(panelMin, panelMax, IM_COL32(24, 26, 29, 220), 7.0f);
    drawList->AddRect(panelMin, panelMax, IM_COL32(255, 255, 255, 28), 7.0f, 0, 1.0f);

    const SceneViewportToolMode toolModes[kToolCount] = {
        SceneViewportToolMode::ViewMove,
        SceneViewportToolMode::Move,
        SceneViewportToolMode::Rotate,
        SceneViewportToolMode::Scale,
        SceneViewportToolMode::Transform
    };

    for (size_t index = 0; index < kToolCount; ++index) {
        const SceneViewportToolMode toolMode = toolModes[index];
        const bool active = toolMode == activeTool;
        const ImVec2 buttonMin(
            panelMin.x + kPanelPadding,
            panelMin.y + kPanelPadding + index * (kButtonExtent + kButtonSpacing));
        const ImVec2 buttonMax(buttonMin.x + kButtonExtent, buttonMin.y + kButtonExtent);

        ImGui::SetCursorScreenPos(buttonMin);
        const std::string buttonId = std::string("##SceneToolButton") + std::to_string(static_cast<int>(toolMode));
        const bool clicked = ImGui::InvisibleButton(
            buttonId.c_str(),
            ImVec2(kButtonExtent, kButtonExtent),
            ImGuiButtonFlags_MouseButtonLeft |
                ImGuiButtonFlags_PressedOnClick |
                ImGuiButtonFlags_AllowOverlap);

        const bool hovered = ImGui::IsItemHovered();
        const bool held = ImGui::IsItemActive();
        result.hovered = result.hovered || hovered;
        result.clicked = result.clicked || clicked;
        if (clicked) {
            result.clickedTool = toolMode;
        }

        const ImU32 backgroundColor = ImGui::GetColorU32(
            held ? UI::ToolbarButtonActiveColor()
                 : hovered ? UI::ToolbarButtonHoveredColor(active)
                           : UI::ToolbarButtonColor(active));
        drawList->AddRectFilled(buttonMin, buttonMax, backgroundColor, 5.0f);
        drawList->AddRect(buttonMin, buttonMax, IM_COL32(255, 255, 255, active ? 48 : 24), 5.0f, 0, 1.0f);

        const ImVec2 iconMin(buttonMin.x + kIconInset, buttonMin.y + kIconInset);
        const ImVec2 iconMax(buttonMax.x - kIconInset, buttonMax.y - kIconInset);
        if (!UI::DrawTextureAssetPreview(
                drawList,
                iconMin,
                iconMax,
                GetSceneViewportToolIconPath(toolMode, active))) {
            drawList->AddText(
                ImVec2(buttonMin.x + 8.0f, buttonMin.y + 7.0f),
                IM_COL32(230, 230, 230, 255),
                GetSceneViewportToolTooltip(toolMode));
        }

        if (hovered) {
            ImGui::SetTooltip("%s", GetSceneViewportToolTooltip(toolMode));
        }
    }

    return result;
}

bool ShouldBeginSceneViewportNavigationDrag(
    bool hasInteractiveViewport,
    bool hovered,
    bool activeDrag,
    bool otherDrag,
    bool gizmoActive,
    ImGuiMouseButton button) {
    return hasInteractiveViewport &&
        hovered &&
        !activeDrag &&
        !otherDrag &&
        !gizmoActive &&
        ImGui::IsMouseClicked(button);
}

} // namespace

SceneViewPanel::SceneViewPanel() : Panel("Scene") {}

void SceneViewPanel::Render() {
    ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
    UI::PanelWindowScope panel(m_name.c_str());
    ImGui::PopStyleVar();
    if (!panel.IsOpen()) {
        return;
    }

    RenderSceneViewportTopBar(m_pivotMode, m_transformSpaceMode);
    const ViewportPanelContentResult content = RenderViewportPanelContent(*m_context, EditorViewportKind::Scene);
    if (IViewportHostService* viewportHostService = m_context->GetViewportHostService()) {
        const ImGuiIO& io = ImGui::GetIO();
        const bool hasInteractiveViewport = content.hasViewportArea && content.frame.hasTexture;
        const SceneViewportToolOverlayResult toolOverlay = RenderSceneViewportToolOverlay(content, m_toolMode);
        const bool viewportContentHovered = content.hovered && !toolOverlay.hovered;

        if (toolOverlay.clicked) {
            if (m_moveGizmo.IsActive()) {
                m_moveGizmo.CancelDrag(&m_context->GetUndoManager());
            }
            if (m_rotateGizmo.IsActive()) {
                m_rotateGizmo.CancelDrag(&m_context->GetUndoManager());
            }
            if (m_scaleGizmo.IsActive()) {
                m_scaleGizmo.CancelDrag(&m_context->GetUndoManager());
            }
            m_toolMode = toolOverlay.clickedTool;
        }

        const bool allowToolShortcut = !io.WantTextInput && !m_lookDragging && !m_panDragging;
        if (allowToolShortcut) {
            if (ImGui::IsKeyPressed(ImGuiKey_Q, false)) {
                if (m_moveGizmo.IsActive()) {
                    m_moveGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                if (m_rotateGizmo.IsActive()) {
                    m_rotateGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                if (m_scaleGizmo.IsActive()) {
                    m_scaleGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                m_toolMode = SceneViewportToolMode::ViewMove;
            } else if (ImGui::IsKeyPressed(ImGuiKey_W, false)) {
                if (m_rotateGizmo.IsActive()) {
                    m_rotateGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                if (m_scaleGizmo.IsActive()) {
                    m_scaleGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                m_toolMode = SceneViewportToolMode::Move;
            } else if (ImGui::IsKeyPressed(ImGuiKey_E, false)) {
                if (m_moveGizmo.IsActive()) {
                    m_moveGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                if (m_scaleGizmo.IsActive()) {
                    m_scaleGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                m_toolMode = SceneViewportToolMode::Rotate;
            } else if (ImGui::IsKeyPressed(ImGuiKey_R, false)) {
                if (m_moveGizmo.IsActive()) {
                    m_moveGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                if (m_rotateGizmo.IsActive()) {
                    m_rotateGizmo.CancelDrag(&m_context->GetUndoManager());
                }
                m_toolMode = SceneViewportToolMode::Scale;
            }
        }

        const bool usingViewMoveTool = m_toolMode == SceneViewportToolMode::ViewMove;
        const bool usingTransformTool = m_toolMode == SceneViewportToolMode::Transform;
        const bool showingMoveGizmo = m_toolMode == SceneViewportToolMode::Move || usingTransformTool;
        const bool showingRotateGizmo = m_toolMode == SceneViewportToolMode::Rotate || usingTransformTool;
        const bool showingScaleGizmo = m_toolMode == SceneViewportToolMode::Scale || usingTransformTool;
        const bool useCenterPivot = m_pivotMode == SceneViewportPivotMode::Center;
        const bool localSpace = m_transformSpaceMode == SceneViewportTransformSpaceMode::Local;
        const SceneViewportTransformGizmoFrameOptions gizmoFrameOptions =
            BuildSceneViewportTransformGizmoFrameOptions(
                useCenterPivot,
                localSpace,
                usingTransformTool,
                showingMoveGizmo,
                showingRotateGizmo,
                showingScaleGizmo);
        const Math::Vector2 viewportSize(content.availableSize.x, content.availableSize.y);
        const Math::Vector2 localMousePosition(
            io.MousePos.x - content.itemMin.x,
            io.MousePos.y - content.itemMin.y);
        SceneViewportOverlayData overlay = {};
        SceneViewportTransformGizmoFrameUpdate interactionGizmoFrame = {};
        SceneViewportTransformGizmoFrameState gizmoFrameState = {};
        SceneViewportOverlayFrameData emptySceneOverlayFrameData = {};

        if (hasInteractiveViewport) {
            overlay = viewportHostService->GetSceneViewOverlayData();
            interactionGizmoFrame = RefreshAndSubmitSceneViewportTransformGizmoFrame(
                *viewportHostService,
                BuildSceneViewportTransformGizmoRefreshRequest(
                    *m_context,
                    overlay,
                    viewportSize,
                    localMousePosition,
                    gizmoFrameOptions),
                m_moveGizmo,
                m_rotateGizmo,
                m_scaleGizmo);
            gizmoFrameState = interactionGizmoFrame.frameState;
        } else {
            CancelSceneViewportTransformGizmoFrame(
                *m_context,
                m_moveGizmo,
                m_rotateGizmo,
                m_scaleGizmo);
        }

        const SceneViewportTransformGizmoOverlaySubmission interactionGizmoSubmission =
            hasInteractiveViewport
            ? interactionGizmoFrame.overlaySubmission
            : SceneViewportTransformGizmoOverlaySubmission{};
        const SceneViewportOverlayFrameData& interactionOverlayFrameData =
            hasInteractiveViewport
            ? viewportHostService->GetSceneViewEditorOverlayFrameData(*m_context)
            : emptySceneOverlayFrameData;
        const SceneViewportActiveGizmoKind activeGizmoKind = interactionGizmoSubmission.activeGizmoKind;
        const bool gizmoActive = interactionGizmoSubmission.GizmoActive();
        const SceneViewportHudOverlayData interactionHudOverlay =
            BuildSceneViewportHudOverlayData(overlay);
        SceneViewportInteractionResult hoveredInteraction = {};
        const bool canResolveViewportInteraction =
            hasInteractiveViewport &&
            viewportContentHovered &&
            !usingViewMoveTool &&
            !m_lookDragging &&
            !m_panDragging &&
            !toolOverlay.hovered &&
            !gizmoActive;
        if (canResolveViewportInteraction) {
            SceneViewportInteractionResolveRequest interactionRequest = {};
            interactionRequest.overlayFrameData = &interactionOverlayFrameData;
            interactionRequest.viewportSize = viewportSize;
            interactionRequest.localMousePosition = localMousePosition;
            interactionRequest.hudOverlay = &interactionHudOverlay;
            interactionRequest.viewportMin = content.itemMin;
            interactionRequest.viewportMax = content.itemMax;
            interactionRequest.absoluteMousePosition = io.MousePos;
            hoveredInteraction = ResolveSceneViewportInteraction(interactionRequest);
        }

        ApplySceneViewportHoveredHandleState(
            BuildSceneViewportHoveredHandleState(hoveredInteraction),
            gizmoActive,
            showingMoveGizmo,
            m_moveGizmo,
            showingRotateGizmo,
            m_rotateGizmo,
            showingScaleGizmo,
            m_scaleGizmo);

        const SceneViewportInteractionActions interactionActions =
            BuildSceneViewportInteractionActions(
                hoveredInteraction,
                hasInteractiveViewport,
                content.clickedLeft,
                canResolveViewportInteraction);
        const bool beginLeftPanDrag = usingViewMoveTool
            ? ShouldBeginSceneViewportNavigationDrag(
                hasInteractiveViewport,
                viewportContentHovered,
                m_panDragging,
                m_lookDragging,
                gizmoActive,
                ImGuiMouseButton_Left)
            : false;
        const bool beginLookDrag = ShouldBeginSceneViewportNavigationDrag(
            hasInteractiveViewport,
            viewportContentHovered,
            m_lookDragging,
            m_panDragging,
            gizmoActive,
            ImGuiMouseButton_Right);
        const bool beginMiddlePanDrag = ShouldBeginSceneViewportNavigationDrag(
            hasInteractiveViewport,
            viewportContentHovered,
            m_panDragging,
            m_lookDragging,
            gizmoActive,
            ImGuiMouseButton_Middle);
        const bool beginPanDrag = beginLeftPanDrag || beginMiddlePanDrag;

        if (toolOverlay.clicked || interactionActions.HasClickAction() || beginLookDrag ||
            beginPanDrag) {
            ImGui::SetWindowFocus();
        }

        ExecuteSceneViewportTransformGizmoLifecycleCommand(
            BuildBeginSceneViewportTransformGizmoLifecycleCommand(interactionActions),
            m_context->GetUndoManager(),
            gizmoFrameState,
            m_moveGizmo,
            m_rotateGizmo,
            m_scaleGizmo);

        DispatchSceneViewportInteractionActions(
            interactionActions,
            *m_context,
            *viewportHostService,
            content.availableSize,
            localMousePosition);

        ExecuteSceneViewportTransformGizmoLifecycleCommand(
            BuildFrameSceneViewportTransformGizmoLifecycleCommand(
                activeGizmoKind,
                ImGui::IsMouseDown(ImGuiMouseButton_Left)),
            m_context->GetUndoManager(),
            gizmoFrameState,
            m_moveGizmo,
            m_rotateGizmo,
            m_scaleGizmo);

        if (beginLookDrag) {
            m_lookDragging = true;
            m_panDragging = false;
            m_loggedLookDelta = false;
            m_loggedPanDelta = false;
        }
        if (beginPanDrag) {
            m_panDragging = true;
            m_lookDragging = false;
            m_panDragButton = beginLeftPanDrag ? ImGuiMouseButton_Left : ImGuiMouseButton_Middle;
            m_loggedPanDelta = false;
            m_loggedLookDelta = false;
        }

        if (m_lookDragging && !ImGui::IsMouseDown(ImGuiMouseButton_Right)) {
            m_lookDragging = false;
            m_loggedLookDelta = false;
        }
        if (m_panDragging && !ImGui::IsMouseDown(m_panDragButton)) {
            m_panDragging = false;
            m_panDragButton = ImGuiMouseButton_Middle;
            m_loggedPanDelta = false;
        }

        if (m_lookDragging || m_panDragging || m_moveGizmo.IsActive() || m_rotateGizmo.IsActive() ||
            m_scaleGizmo.IsActive()) {
            ImGui::SetNextFrameWantCaptureMouse(true);
        }
        if (m_lookDragging) {
            ImGui::SetNextFrameWantCaptureKeyboard(true);
        }

        SceneViewportInput input = {};
        input.viewportSize = content.availableSize;
        input.deltaTime = io.DeltaTime;
        input.hovered = viewportContentHovered;
        input.focused = content.focused || m_lookDragging || m_panDragging;
        input.mouseWheel = (viewportContentHovered && !m_lookDragging) ? io.MouseWheel : 0.0f;
        input.flySpeedDelta = (viewportContentHovered && m_lookDragging) ? io.MouseWheel : 0.0f;
        input.looking = m_lookDragging;
        input.orbiting = false;
        input.panning = m_panDragging;
        input.fastMove = io.KeyShift;
        input.focusSelectionRequested =
            input.focused && !io.WantTextInput && ImGui::IsKeyPressed(ImGuiKey_F, false);

        if (m_lookDragging && !io.WantTextInput) {
            input.moveForward =
                (ImGui::IsKeyDown(ImGuiKey_W) ? 1.0f : 0.0f) -
                (ImGui::IsKeyDown(ImGuiKey_S) ? 1.0f : 0.0f);
            input.moveRight =
                (ImGui::IsKeyDown(ImGuiKey_D) ? 1.0f : 0.0f) -
                (ImGui::IsKeyDown(ImGuiKey_A) ? 1.0f : 0.0f);
            input.moveUp =
                (ImGui::IsKeyDown(ImGuiKey_E) ? 1.0f : 0.0f) -
                (ImGui::IsKeyDown(ImGuiKey_Q) ? 1.0f : 0.0f);
        }

        if (m_lookDragging || m_panDragging) {
            if (m_lookDragging) {
                input.mouseDelta = io.MouseDelta;
                if (!m_loggedLookDelta &&
                    (input.mouseDelta.x != 0.0f || input.mouseDelta.y != 0.0f)) {
                    m_loggedLookDelta = true;
                }
            }

            if (m_panDragging) {
                input.mouseDelta = io.MouseDelta;
                if (!m_loggedPanDelta &&
                    (input.mouseDelta.x != 0.0f || input.mouseDelta.y != 0.0f)) {
                    m_loggedPanDelta = true;
                }
            }
        }

        viewportHostService->UpdateSceneViewInput(*m_context, input);

        if (content.hasViewportArea && content.frame.hasTexture) {
            overlay = viewportHostService->GetSceneViewOverlayData();
            RefreshAndSubmitSceneViewportTransformGizmoFrame(
                *viewportHostService,
                BuildSceneViewportTransformGizmoRefreshRequest(
                    *m_context,
                    overlay,
                    viewportSize,
                    localMousePosition,
                    gizmoFrameOptions),
                m_moveGizmo,
                m_rotateGizmo,
                m_scaleGizmo);

            DrawSceneViewportHudOverlay(
                ImGui::GetWindowDrawList(),
                BuildSceneViewportHudOverlayData(overlay),
                content.itemMin,
                content.itemMax);
        }
    }

    Actions::ObserveInactiveActionRoute(*m_context);
}

}
}