3D viewer violations

[openroad-ci]

Fix the issue :
#9412

[gemini-code-assist]

Code Review

This pull request introduces significant enhancements to the 3D chiplet viewer, transitioning it from a wireframe display to a more advanced solid-rendered view. Key improvements include lighting effects, back-face culling, and depth sorting using a painter's algorithm. The viewer is now more interactive, with features like zooming to selected objects and selection-focus animations. The implementation is robust, leveraging modern C++ and performance optimizations such as reusing buffers during painting. The integration with the main window's selection and highlight system is also well-executed. My review includes a couple of suggestions to replace a magic number with a named constant to improve code maintainability, aligning with repository guidelines.

[gemini-code-assist]

The Z-scaling factor 2.0f is used here as a magic number. To improve readability and maintainability, consider defining it as a named constant (e.g., constexpr float kZScale = 2.0f;) in the anonymous namespace at the top of the file. This magic number is also used on line 371.

Suggested change

	vertices_.push_back({QVector3D(p.x(), p.y(), p.z() * 2.0f), color});
	vertices_.push_back({QVector3D(p.x(), p.y(), p.z() * kZScale), color});

References

1. Define tunable parameters as named constants instead of using hardcoded magic numbers.

[gemini-code-assist]

The Z-scaling factor 2.0f is used here as a magic number. To improve readability and maintainability, consider using the named constant suggested for line 216.

Suggested change

	target_z = draw_cuboid.zMax() * 2.0f + kHighlightZOffset;
	target_z = draw_cuboid.zMax() * kZScale + kHighlightZOffset;

References

1. Define tunable parameters as named constants instead of using hardcoded magic numbers.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[jferreiraOpenRoad]

🎨 Visual Improvements & Rendering

Solid Chiplet Visualization: Transitioned from wireframe-only to solid-filled face rendering.

    Painter’s Algorithm: Implemented depth sorting (sorted_faces_) to ensure correct draw order (back-to-front).

    Back-Face Culling: Added logic to skip rendering faces not oriented toward the camera, preventing visual artifacts and overlapping during rotation.

Lighting & Shading: Added a simple facet-based lighting model to improve spatial perception:

    Top faces: Rendered brighter.

    Side/Bottom faces: Rendered darker to provide a clear sense of depth and volume.

Expanded Color Palette: Added Teal, Purple, and Pink to better differentiate between chiplets.

    Note: Yellow has been intentionally excluded from the random palette as it is reserved for DRC/Selection highlights.

Z-Axis Scaling: Introduced a configurable scale factor (kZScale = 2.0f) to visually exaggerate the height of chiplet structures, which are often too thin to inspect at a 1:1 ratio.

🖱️ Interaction & Navigation

Synchronized Selection & Highlighting:

    The 3D viewer is now fully synced with the Layout Viewer and DRC Viewer.

    Highlighted objects are rendered with thicker outlines and a yellow fill to match the main UI's visual language.

    Added a selectionFocus animation (pulse/flash effect) to help users quickly locate small components.

Smart Zoom & Auto-Focus:

    Implemented zoomTo(): Automatically centers the camera and adjusts the zoom level to fit the selected object.

    Top-Down Reset: When focusing on a selection, the camera rotation resets to a 2D-like top view for easier localization.

Enhanced Camera Controls:

    Improved panning logic and implemented strict zoom bounds (kMinDistanceBound, kMaxDistanceBound) to prevent the camera from clipping through geometry or "getting lost" in space.

🛠️ Technical Details & Optimization

MainWindow Integration:

    The Chiplet3DWidget now maintains active references to selected_ and highlighted_ sets from the main window.

    Connected new signals to trigger automatic updates whenever changes occur in the Inspector or DRC Viewer.

Performance Optimizations:

    Memory Management: Introduced reusable buffers (polygon_buffer_, face_view_points_) to eliminate heap allocations within the paintEvent loop, significantly reducing CPU overhead during high-FPS interaction.

[osamahammad21]

In general, when I tested this branch I found the following:

• Zoom function is messed up because of the clamping values
• The faces draw over each other in specific angles
• Although hovering over the violation from the DRC widget animates one of the faces of the violating chiplets, it does not highlight the chiplet when the violation is selected.
• Instead of highlighting the chiplet, you should highlight the violation cuboid (minor and could be addressed in a separate PR).
• The drawn matrix changes its z coordinate with different distance_ values

[osamahammad21]

Is there a logical explanation behind the values of the constants kMinDistanceBound and kMaxDistanceBound? They cause a problem when the distance_ is out of these bounds.