Graphic Rendering Near Clipping Plane Intersection Handling
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Solution Overview
Problem
Conventional graphic rendering systems face computational complexity and burden when processing objects close to or behind the camera, leading to issues like division by zero and incorrect clipping, which increases processing load and complexity.
Innovation Solution
A graphic rendering system that determines the intersection vertices of edge functions with the near clipping plane and transforms these vertices into screen space, adjusting edge functions with a minus sign as needed to define a valid area, thereby reducing computational burden and preventing rendering errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional clipping methods are used to handle objects close to or behind the camera, then rendering accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent extracts and handles the near clipping plane separately from the other view volume planes. By identifying when a primitive intersects only the near clipping plane (case c) and applying specialized handling for this specific scenario, the system avoids the complex general-purpose clipping algorithms that would be required to handle all six planes uniformly, thus reducing computational complexity while maintaining rendering accuracy.
Solution Approach 2:
The patent segments the clipping process into distinct cases based on the position of primitive vertices relative to the view volume. By dividing the problem into specific scenarios (all vertices inside, all vertices outside, or mixed positions) and applying optimized handling for each case, particularly for near-clipping scenarios, the system reduces overall computational complexity compared to applying a single complex clipping algorithm to all cases.
2Reliability
If clipping is performed against all six planes of the view volume, then rendering reliability is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary classification of primitives based on vertex positions before executing the full clipping process. By pre-identifying primitives that fall into specific categories (such as those intersecting only the near clipping plane), the system can apply optimized, simplified clipping operations only when necessary, rather than performing comprehensive six-plane clipping on all primitives, thus reducing processing time while maintaining rendering reliability.
Solution Approach 2:
The patent applies partial clipping action by handling only the necessary planes for each primitive based on its specific position. For primitives close to or intersecting the near clipping plane, the system performs clipping only against the relevant planes rather than all six view volume planes, reducing processing time while maintaining sufficient rendering reliability for the specific case.
3Reliability
If multiple triangles are generated through clipping, then rendering completeness is improved, but device burden increases
Solution Approach 1:
The patent extracts and optimizes the handling of the near clipping plane case specifically. By identifying when a primitive intersects only the near clipping plane and applying a specialized algorithm for this scenario, the system generates the necessary triangles to maintain rendering completeness while avoiding the excessive triangle generation that would result from applying general-purpose clipping algorithms to this specific case.
Data Source
AI summary
A graphic rendering system and a projection method thereof are provided. The graphic rendering system comprises a processing unit and a storage unit. The storage unit stores a piece of information. The information defines a virtual area in a camera space, wherein the virtual area has three vertices. The processing unit calculates two intersection vertices between the virtual area and near clipping plane of a view volume of the camera space. The processing unit transforms the three vertices and the two intersection vertices to a screen space and derives three projection vertices and two projection intersection vertices. The processing unit decides a valid area, chooses a test vertex from the valid area, and decides whether the signs of the three projection edge functions defined by the three projection vertices should be changed. Then, the processing unit decides pixels to be rendered according to the valid area, projection edge functions, and a predefined window clipping region.