Dynamic Soft Shadow Rendering in VR
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Solution Overview
Problem
Conventional methods for creating soft shadows in real-time on untethered VR devices, such as head-mounted displays, are computationally expensive and exceed thermal limits due to the need for multiple rendering passes and high processing power, resulting in lower image quality and potential overheating.
Innovation Solution
A method to generate dynamic soft shadows in a single pass using a shader script that determines shadow position, size, fading, and sharpness based on the position and size of the shadow casting element and light vector, eliminating the need for multiple render passes and lightmap generation, thus reducing computational resources required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple rendering passes and sampling are used to achieve soft shadow effect, then shadow quality is improved, but computational cost and power consumption increase significantly
Solution Approach 1:
The patent changes the rendering approach by using a single-pass technique with modified shadow map parameters. Instead of multiple rendering passes, it uses a conventional shadow map with adjusted sampling parameters and a soft shadow shader that calculates penumbra regions through mathematical operations on shadow coordinates, achieving soft shadows with reduced computational cost.
Solution Approach 2:
The patent extracts the soft shadow calculation from the traditional multi-pass rendering process. By separating the shadow mapping step from the soft shadow rendering step, it allows the use of a conventional shadow map without requiring multiple passes, thus reducing power consumption while maintaining shadow quality.
2Manufacturing precision
If multiple rendering passes are used to generate soft shadows, then shadow realism is improved, but processing time and computational resources increase
Solution Approach 1:
The patent modifies the shadow rendering parameters by using a single-pass approach with adjusted sampling rates and shadow map resolutions. The soft shadow shader performs coordinate transformations and blending operations that achieve realistic soft shadows without the time cost of multiple rendering passes.
Solution Approach 2:
The patent uses a conventional shadow map as a base and creates soft shadows by copying and transforming shadow information through shader operations. Instead of generating multiple shadow maps through multiple passes, it copies shadow data and processes it mathematically to produce penumbra effects, reducing processing time.
3Manufacturing precision
If higher processing power is used to render realistic shadows in real-time, then shadow quality is improved, but heat generation increases and thermal limits are exceeded
Solution Approach 1:
The patent changes the processing parameters by implementing a single-pass shadow rendering technique. This reduces the computational load and power consumption, thereby decreasing heat generation and preventing thermal limits from being exceeded while still delivering realistic shadow quality through optimized shader calculations.
4Ease of manufacture
If conventional shadow rendering techniques are used on untethered VR devices, then implementation simplicity is maintained, but computational cost exceeds device capabilities
Solution Approach 1:
The patent adjusts the rendering parameters to be compatible with untethered VR device capabilities. By using a single-pass technique with optimized shadow map parameters and efficient shader operations, it maintains implementation simplicity while reducing computational power requirements to fit within device constraints.
Data Source
Figure 1A~1E
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AI summary
Dynamic soft shadows may be generated without resorting to computationally-expensive multiple render passes and sampling, or lightmap generation. With disclosed systems and methods, a dynamic soft shadow may be rendered in a single pass, which is sufficiently efficient to run on an untethered virtual reality (VR) device, such as a head mounted device (HMD). Despite the efficiency, the shadow quality may be markedly superior to those generated with other methods. In some embodiments, a script may be used with a shader to render a shadow having a realistic size, shape, position, fading factor and sharpness, based on a position and size of a shadow casting element and a light vector.