XCEngine/editor/src/Viewport/SceneViewportOverlayRenderer.cpp

#include "SceneViewportOverlayRenderer.h"
#include "SceneViewportOrientationGizmo.h"

#include <algorithm>

namespace XCEngine {
namespace Editor {

namespace {

ImU32 ToImGuiColor(const Math::Color& color) {
    const auto toChannel = [](float value) -> int {
        return static_cast<int>(std::clamp(value, 0.0f, 1.0f) * 255.0f + 0.5f);
    };

    return IM_COL32(
        toChannel(color.r),
        toChannel(color.g),
        toChannel(color.b),
        toChannel(color.a));
}

void DrawSceneMoveGizmo(
    ImDrawList* drawList,
    const ImVec2& viewportMin,
    const SceneViewportMoveGizmoDrawData& moveGizmo) {
    if (drawList == nullptr || !moveGizmo.visible) {
        return;
    }

    const ImVec2 pivot(viewportMin.x + moveGizmo.pivot.x, viewportMin.y + moveGizmo.pivot.y);
    drawList->AddCircleFilled(pivot, moveGizmo.pivotRadius + 1.0f, IM_COL32(20, 22, 24, 220), 20);
    drawList->AddCircle(pivot, moveGizmo.pivotRadius + 1.0f, IM_COL32(255, 255, 255, 48), 20, 1.0f);

    for (const SceneViewportMoveGizmoHandleDrawData& handle : moveGizmo.handles) {
        if (!handle.visible) {
            continue;
        }

        const ImU32 color = ToImGuiColor(handle.color);
        const float thickness = handle.active ? 4.0f : (handle.hovered ? 3.0f : 2.0f);
        const ImVec2 start(viewportMin.x + handle.start.x, viewportMin.y + handle.start.y);
        const ImVec2 end(viewportMin.x + handle.end.x, viewportMin.y + handle.end.y);
        drawList->AddLine(start, end, color, thickness);
        drawList->AddCircleFilled(end, handle.active ? 6.5f : 5.5f, color, 20);
    }
}

} // namespace

void DrawSceneViewportOverlay(
    ImDrawList* drawList,
    const SceneViewportOverlayData& overlay,
    const ImVec2& viewportMin,
    const ImVec2& viewportMax,
    const ImVec2& viewportSize,
    const SceneViewportMoveGizmoDrawData* moveGizmo) {
    if (drawList == nullptr || viewportSize.x <= 1.0f || viewportSize.y <= 1.0f) {
        return;
    }

    drawList->PushClipRect(viewportMin, viewportMax, true);
    if (overlay.valid) {
        DrawSceneViewportOrientationGizmo(drawList, overlay, viewportMin, viewportMax);
    }
    if (moveGizmo != nullptr) {
        DrawSceneMoveGizmo(drawList, viewportMin, *moveGizmo);
    }
    drawList->PopClipRect();
}

} // namespace Editor
} // namespace XCEngine