feat: refine scene viewport gizmos and controls

editor/src/Viewport/SceneViewportOverlayRenderer.cpp

@@ -2,12 +2,16 @@
 #include "SceneViewportOrientationGizmo.h"
 
 #include <algorithm>
+#include <cmath>
 
 namespace XCEngine {
 namespace Editor {
 
 namespace {
 
+constexpr float kMoveGizmoArrowLength = 14.0f;
+constexpr float kMoveGizmoArrowHalfWidth = 7.0f;
+
 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);
@@ -20,6 +24,69 @@ ImU32 ToImGuiColor(const Math::Color& color) {
         toChannel(color.a));
 }
 
+ImVec2 NormalizeImVec2(const ImVec2& value, const ImVec2& fallback = ImVec2(1.0f, 0.0f)) {
+    const float lengthSq = value.x * value.x + value.y * value.y;
+    if (lengthSq <= 1e-6f) {
+        return fallback;
+    }
+
+    const float inverseLength = 1.0f / std::sqrt(lengthSq);
+    return ImVec2(value.x * inverseLength, value.y * inverseLength);
+}
+
+void DrawSceneMoveGizmoPlane(
+    ImDrawList* drawList,
+    const ImVec2& viewportMin,
+    const SceneViewportMoveGizmoPlaneDrawData& plane) {
+    if (drawList == nullptr || !plane.visible) {
+        return;
+    }
+
+    ImVec2 points[4] = {};
+    for (size_t index = 0; index < plane.corners.size(); ++index) {
+        points[index] = ImVec2(
+            viewportMin.x + plane.corners[index].x,
+            viewportMin.y + plane.corners[index].y);
+    }
+
+    drawList->AddConvexPolyFilled(points, 4, ToImGuiColor(plane.fillColor));
+    drawList->AddPolyline(
+        points,
+        4,
+        ToImGuiColor(plane.outlineColor),
+        true,
+        plane.active ? 2.6f : (plane.hovered ? 2.0f : 1.4f));
+}
+
+void DrawSceneMoveGizmoAxis(
+    ImDrawList* drawList,
+    const ImVec2& viewportMin,
+    const SceneViewportMoveGizmoHandleDrawData& handle) {
+    if (drawList == nullptr || !handle.visible) {
+        return;
+    }
+
+    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);
+    const ImVec2 direction = NormalizeImVec2(ImVec2(end.x - start.x, end.y - start.y));
+    const ImVec2 normal(-direction.y, direction.x);
+    const ImVec2 arrowBase(
+        end.x - direction.x * kMoveGizmoArrowLength,
+        end.y - direction.y * kMoveGizmoArrowLength);
+    const ImVec2 arrowLeft(
+        arrowBase.x + normal.x * kMoveGizmoArrowHalfWidth,
+        arrowBase.y + normal.y * kMoveGizmoArrowHalfWidth);
+    const ImVec2 arrowRight(
+        arrowBase.x - normal.x * kMoveGizmoArrowHalfWidth,
+        arrowBase.y - normal.y * kMoveGizmoArrowHalfWidth);
+
+    drawList->AddLine(start, arrowBase, color, thickness);
+    const ImVec2 triangle[3] = { end, arrowLeft, arrowRight };
+    drawList->AddConvexPolyFilled(triangle, 3, color);
+}
+
 void DrawSceneMoveGizmo(
     ImDrawList* drawList,
     const ImVec2& viewportMin,
@@ -29,21 +96,16 @@ void DrawSceneMoveGizmo(
     }
 
     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 SceneViewportMoveGizmoPlaneDrawData& plane : moveGizmo.planes) {
+        DrawSceneMoveGizmoPlane(drawList, viewportMin, plane);
+    }
 
     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);
+        DrawSceneMoveGizmoAxis(drawList, viewportMin, handle);
     }
+
+    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);
 }
 
 } // namespace