XCEngine/tests/editor/test_scene_viewport_move_gizmo.cpp

#include <gtest/gtest.h>

#include <cmath>

#include "Core/EditorContext.h"
#include "Managers/SceneManager.h"
#include "Viewport/SceneViewportMoveGizmo.h"

namespace XCEngine::Editor {
namespace {

float HandleLength(const SceneViewportMoveGizmoHandleDrawData& handle) {
    return (handle.end - handle.start).Magnitude();
}

Math::Vector2 QuadCenter(const SceneViewportMoveGizmoPlaneDrawData& plane) {
    Math::Vector2 center = Math::Vector2::Zero();
    for (const Math::Vector2& corner : plane.corners) {
        center += corner;
    }

    return center / 4.0f;
}

class SceneViewportMoveGizmoTest : public ::testing::Test {
protected:
    void SetUp() override {
        m_context.GetSceneManager().NewScene("Move Gizmo Test Scene");
    }

    static SceneViewportOverlayData MakeOverlay() {
        SceneViewportOverlayData overlay = {};
        overlay.valid = true;
        overlay.cameraPosition = Math::Vector3(0.0f, 0.0f, -5.0f);
        overlay.cameraForward = Math::Vector3::Forward();
        overlay.cameraRight = Math::Vector3::Right();
        overlay.cameraUp = Math::Vector3::Up();
        overlay.verticalFovDegrees = 60.0f;
        overlay.nearClipPlane = 0.03f;
        overlay.farClipPlane = 2000.0f;
        return overlay;
    }

    static SceneViewportOverlayData MakeDownwardTiltedOverlay() {
        SceneViewportOverlayData overlay = {};
        overlay.valid = true;
        overlay.cameraPosition = Math::Vector3(0.0f, 10.0f, -1.0f);
        overlay.cameraForward = (Math::Vector3::Zero() - overlay.cameraPosition).Normalized();
        overlay.cameraRight = Math::Vector3::Cross(Math::Vector3::Up(), overlay.cameraForward).Normalized();
        overlay.cameraUp = Math::Vector3::Cross(overlay.cameraForward, overlay.cameraRight).Normalized();
        overlay.verticalFovDegrees = 60.0f;
        overlay.nearClipPlane = 0.03f;
        overlay.farClipPlane = 2000.0f;
        return overlay;
    }

    static SceneViewportOverlayData MakeIsometricOverlay() {
        SceneViewportOverlayData overlay = {};
        overlay.valid = true;
        overlay.cameraPosition = Math::Vector3(-5.0f, 5.0f, -5.0f);
        overlay.cameraForward = (Math::Vector3::Zero() - overlay.cameraPosition).Normalized();
        overlay.cameraRight = Math::Vector3::Cross(Math::Vector3::Up(), overlay.cameraForward).Normalized();
        overlay.cameraUp = Math::Vector3::Cross(overlay.cameraForward, overlay.cameraRight).Normalized();
        overlay.verticalFovDegrees = 60.0f;
        overlay.nearClipPlane = 0.03f;
        overlay.farClipPlane = 2000.0f;
        return overlay;
    }

    static SceneViewportMoveGizmoContext MakeContext(
        Components::GameObject* selectedObject,
        const Math::Vector2& mousePosition) {
        SceneViewportMoveGizmoContext context = {};
        context.overlay = MakeOverlay();
        context.viewportSize = Math::Vector2(800.0f, 600.0f);
        context.mousePosition = mousePosition;
        context.selectedObject = selectedObject;
        return context;
    }

    static SceneViewportMoveGizmoContext MakeContext(
        Components::GameObject* selectedObject,
        const Math::Vector2& mousePosition,
        const SceneViewportOverlayData& overlay) {
        SceneViewportMoveGizmoContext context = {};
        context.overlay = overlay;
        context.viewportSize = Math::Vector2(800.0f, 600.0f);
        context.mousePosition = mousePosition;
        context.selectedObject = selectedObject;
        return context;
    }

    SceneManager& GetSceneManager() {
        return dynamic_cast<SceneManager&>(m_context.GetSceneManager());
    }

    EditorContext m_context;
};

TEST_F(SceneViewportMoveGizmoTest, UpdateHighlightsXAxisWhenMouseIsNearXAxisHandle) {
    Components::GameObject* target = GetSceneManager().CreateEntity("Target");
    ASSERT_NE(target, nullptr);
    m_context.GetSelectionManager().SetSelectedEntity(target->GetID());

    SceneViewportMoveGizmo gizmo;
    gizmo.Update(MakeContext(target, Math::Vector2(436.0f, 300.0f)));

    ASSERT_TRUE(gizmo.GetDrawData().visible);
    EXPECT_TRUE(gizmo.IsHoveringHandle());
    EXPECT_TRUE(gizmo.GetDrawData().handles[0].hovered);
    EXPECT_FALSE(gizmo.GetDrawData().handles[1].hovered);
    EXPECT_FALSE(gizmo.GetDrawData().handles[2].hovered);
}

TEST_F(SceneViewportMoveGizmoTest, DraggingXAxisOnlyChangesWorldXAndCreatesUndoStep) {
    Components::GameObject* target = GetSceneManager().CreateEntity("Target");
    ASSERT_NE(target, nullptr);
    const uint64_t targetId = target->GetID();
    m_context.GetSelectionManager().SetSelectedEntity(target->GetID());

    SceneViewportMoveGizmo gizmo;
    const auto startContext = MakeContext(target, Math::Vector2(436.0f, 300.0f));
    gizmo.Update(startContext);

    ASSERT_TRUE(gizmo.TryBeginDrag(startContext, m_context.GetUndoManager()));
    ASSERT_TRUE(gizmo.IsActive());

    const auto dragContext = MakeContext(target, Math::Vector2(500.0f, 300.0f));
    gizmo.Update(dragContext);
    gizmo.UpdateDrag(dragContext);
    gizmo.EndDrag(m_context.GetUndoManager());

    const Math::Vector3 movedPosition = target->GetTransform()->GetPosition();
    EXPECT_GT(movedPosition.x, 0.05f);
    EXPECT_NEAR(movedPosition.y, 0.0f, 1e-4f);
    EXPECT_NEAR(movedPosition.z, 0.0f, 1e-4f);
    EXPECT_TRUE(m_context.GetUndoManager().CanUndo());

    m_context.GetUndoManager().Undo();
    Components::GameObject* restoredTarget = GetSceneManager().GetEntity(targetId);
    ASSERT_NE(restoredTarget, nullptr);
    const Math::Vector3 restoredPosition = restoredTarget->GetTransform()->GetPosition();
    EXPECT_NEAR(restoredPosition.x, 0.0f, 1e-4f);
    EXPECT_NEAR(restoredPosition.y, 0.0f, 1e-4f);
    EXPECT_NEAR(restoredPosition.z, 0.0f, 1e-4f);
}

TEST_F(SceneViewportMoveGizmoTest, AxisNearlyFacingCameraShrinksInsteadOfKeepingFullLength) {
    Components::GameObject* target = GetSceneManager().CreateEntity("Target");
    ASSERT_NE(target, nullptr);

    SceneViewportMoveGizmo gizmo;
    gizmo.Update(MakeContext(target, Math::Vector2(400.0f, 300.0f), MakeDownwardTiltedOverlay()));

    ASSERT_TRUE(gizmo.GetDrawData().visible);
    const float xLength = HandleLength(gizmo.GetDrawData().handles[0]);
    const float yLength = HandleLength(gizmo.GetDrawData().handles[1]);
    const float zLength = HandleLength(gizmo.GetDrawData().handles[2]);

    EXPECT_GT(xLength, 60.0f);
    EXPECT_GT(zLength, 60.0f);
    EXPECT_LT(yLength, xLength * 0.5f);
    EXPECT_LT(yLength, zLength * 0.5f);
}

TEST_F(SceneViewportMoveGizmoTest, IsometricViewShowsPlaneHandleAndCanHoverIt) {
    Components::GameObject* target = GetSceneManager().CreateEntity("Target");
    ASSERT_NE(target, nullptr);

    SceneViewportMoveGizmo gizmo;
    const SceneViewportOverlayData overlay = MakeIsometricOverlay();
    gizmo.Update(MakeContext(target, Math::Vector2(400.0f, 300.0f), overlay));

    ASSERT_TRUE(gizmo.GetDrawData().visible);
    const SceneViewportMoveGizmoPlaneDrawData& xyPlane = gizmo.GetDrawData().planes[0];
    ASSERT_TRUE(xyPlane.visible);

    gizmo.Update(MakeContext(target, QuadCenter(xyPlane), overlay));

    EXPECT_TRUE(gizmo.IsHoveringHandle());
    EXPECT_TRUE(gizmo.GetDrawData().planes[0].hovered);
    EXPECT_FALSE(gizmo.GetDrawData().planes[1].hovered);
    EXPECT_FALSE(gizmo.GetDrawData().planes[2].hovered);
}

TEST_F(SceneViewportMoveGizmoTest, DraggingXYPlaneChangesWorldXAndYButKeepsZ) {
    Components::GameObject* target = GetSceneManager().CreateEntity("Target");
    ASSERT_NE(target, nullptr);
    const uint64_t targetId = target->GetID();

    SceneViewportMoveGizmo gizmo;
    const SceneViewportOverlayData overlay = MakeIsometricOverlay();
    gizmo.Update(MakeContext(target, Math::Vector2(400.0f, 300.0f), overlay));

    const SceneViewportMoveGizmoPlaneDrawData& xyPlane = gizmo.GetDrawData().planes[0];
    ASSERT_TRUE(xyPlane.visible);

    const Math::Vector2 startMouse = QuadCenter(xyPlane);
    const auto startContext = MakeContext(target, startMouse, overlay);
    gizmo.Update(startContext);
    ASSERT_TRUE(gizmo.TryBeginDrag(startContext, m_context.GetUndoManager()));
    ASSERT_TRUE(gizmo.IsActive());

    const auto dragContext = MakeContext(target, startMouse + Math::Vector2(48.0f, -24.0f), overlay);
    gizmo.Update(dragContext);
    gizmo.UpdateDrag(dragContext);
    gizmo.EndDrag(m_context.GetUndoManager());

    const Math::Vector3 movedPosition = target->GetTransform()->GetPosition();
    EXPECT_GT(std::abs(movedPosition.x), 0.05f);
    EXPECT_GT(std::abs(movedPosition.y), 0.05f);
    EXPECT_NEAR(movedPosition.z, 0.0f, 1e-4f);
    EXPECT_TRUE(m_context.GetUndoManager().CanUndo());

    m_context.GetUndoManager().Undo();
    Components::GameObject* restoredTarget = GetSceneManager().GetEntity(targetId);
    ASSERT_NE(restoredTarget, nullptr);
    const Math::Vector3 restoredPosition = restoredTarget->GetTransform()->GetPosition();
    EXPECT_NEAR(restoredPosition.x, 0.0f, 1e-4f);
    EXPECT_NEAR(restoredPosition.y, 0.0f, 1e-4f);
    EXPECT_NEAR(restoredPosition.z, 0.0f, 1e-4f);
}

} // namespace
} // namespace XCEngine::Editor