Real-time Shadow Rendering via Cached Maps and Deferred Shading
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Solution Overview
Problem
Current technologies face challenges in rendering shadows for real-time interactive video, particularly in night scenes with multiple lights, as it introduces noticeable lag due to the complexity of computing realistic shadows from each light source.
Innovation Solution
The method employs cached shadow maps and deferred shading, where a viewpoint is determined based on user input, and texels of a frame-specific shadow map are filtered using a dynamic mask, combining static and dynamic shadow maps to reduce computational burden and enhance rendering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If realistic shadow rendering is performed for each light source, then shadow quality and realism are improved, but rendering time and computational complexity increase
Solution Approach 1:
The patent pre-calculates and caches shadow maps for static objects and lights before runtime. These cached shadow maps store pre-computed shadow information that can be quickly applied during real-time rendering, eliminating the need to recalculate shadows from scratch for each frame.
Solution Approach 2:
The patent divides the shadow rendering process into separate static and dynamic components. Static shadows are pre-computed and cached, while only dynamic shadows requiring real-time calculation are rendered actively. This segmentation allows the system to handle many lights without proportionally increasing real-time computational burden.
2Adaptability or versatility
If the number of shadow-casting lights is increased, then scene visual complexity and realism are improved, but rendering complexity and lag increase
Solution Approach 1:
Shadow maps for static lights are pre-computed and cached before runtime. During real-time rendering, the system only needs to combine these cached static shadow maps with dynamically computed shadow maps, rather than computing all shadows from scratch. This allows support for many lights without proportionally increasing real-time computational complexity.
Solution Approach 2:
The patent merges cached static shadow maps with dynamically computed shadow maps to produce the final shadow rendering. This combination approach allows the system to leverage pre-computed data for static elements while handling only the necessary dynamic elements in real-time, enabling support for a large number of lights.
3Manufacturing precision
If high resolution shadow maps are used, then shadow detail and quality are improved, but memory usage and processing load increase
Solution Approach 1:
High-resolution shadow maps are pre-computed and cached for static lights during an offline preparation phase. This allows the system to store detailed shadow information in memory without impacting real-time rendering performance, as the data is prepared in advance and only combined with dynamic shadows during runtime.
Data Source
AI summary
A method for real-time shadow rendering using cached shadow maps and deferred shading by a video processor of a game console or the like includes, for at least each key frame of video output, determining a viewpoint for a current key frame based on user input, filtering a texel of a frame-specific shadow map based on a dynamic mask wherein the texel is filtered, for a shadowed light, from a static shadow map and a dynamic shadow map or from the static shadow map only, based on the dynamic mask value for the texel, and rendering the current key frame based on the frame-specific shadow map and a deferred-shadow rendering algorithm. The method enables efficient rendering of thousands of shadowed lights in large environments by consumer-grade game consoles.