Fast Polygon Clipping Using L-Shaped Rendering Region
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Solution Overview
Problem
Existing polygon clipping methods in computer graphics are computationally intensive and time-consuming, particularly in mobile devices where resources are limited.
Innovation Solution
A method and system for fast polygon clipping using an L-shaped rendering region, where a candidate polygon is clipped against this region to render only the visible portions, improving rendering speeds by up to 6 to 8 times compared to traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional polygon clipping methods (Sutherland-Hodgman, Liang-Barsky) are used, then accurate clipping results are achieved, but computational resources and rendering time are excessive
Solution Approach 1:
The patent segments the clipping problem into two distinct phases: (1) coarse culling using axis-aligned bounding boxes (AABB) to quickly eliminate polygons completely outside the view frustum, and (2) precise clipping only for polygons that pass the coarse test. This segmentation reduces the number of polygons requiring intensive clipping operations, thereby improving rendering speed while maintaining clipping accuracy for visible polygons.
Solution Approach 2:
The patent applies partial action by performing only the necessary clipping operations. Instead of clipping all polygons against the complete view frustum boundaries, the method performs coarse culling first and applies precise clipping only to the subset of polygons that may be visible. This partial application of clipping operations significantly reduces computational load while ensuring accurate results for all potentially visible polygons.
2Reliability
If traditional polygon clipping methods are used, then complete visibility determination is achieved, but processing time per frame is excessive
Solution Approach 1:
The patent performs preliminary action through coarse culling using axis-aligned bounding boxes before executing time-consuming precise clipping operations. By预先 (in advance) eliminating polygons that are definitely outside the view frustum using simple AABB tests, the method reduces the number of polygons requiring detailed clipping processing, thereby decreasing processing time per frame while maintaining reliable visibility determination for all candidate polygons.
3Manufacturing precision
If conventional clipping algorithms are applied to all polygons, then accurate rendering is ensured, but computational resources are excessively consumed
Solution Approach 1:
The patent segments polygon processing into two energy-consuming operations with different computational costs: low-cost AABB-based coarse culling and high-cost precise clipping. By segmenting the workload this way, the method ensures that expensive precise clipping operations are performed only on a small subset of polygons that pass the coarse test, thereby reducing total computational resource consumption while maintaining rendering accuracy for visible polygons.
Solution Approach 2:
The patent applies precise clipping operations partially, only to polygons that survive the coarse culling phase. This partial application ensures that computational resources are not wasted on polygons that will definitely be culled, while still guaranteeing rendering accuracy for all polygons that may be visible. The energy consumption is optimized by performing the expensive operation only when necessary.
Data Source
AI summary
A method for rendering static graphics in a mobile device in applications such as map applications. Panning increments are received for panning a previously rendered frame to a panned frame. A rendering region is then determined based on the panning increment. A candidate polygon is then clipped to create clipped polygons contained within the rendering region. The clipped polygons can then be rendered, and a portion of the previously rendered frame can be copied, to provide the panned frame.