Shader-Dependent Fragment Rendering with Two-Stage Execution
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Solution Overview
Problem
Deferred rendering systems face inefficiencies and latency due to the processing of punch through fragments, which have shader-dependent presence, causing unnecessary processing and resource wastage, particularly in graphics processing units (GPUs).
Innovation Solution
The shader program for punch through fragments is split into two stages, with the first stage determining the fragment's presence and the second stage executing only if the fragment survives the initial processing, allowing the depth and tag buffers to be updated only after the presence is confirmed, reducing latency and resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the shader program is executed completely for punch through fragments in deferred rendering systems, then the fragment rendering can be performed, but unnecessary processing and resource wastage occur due to shader-dependent presence
Solution Approach 1:
The shader program is divided into two distinct stages: a first stage that determines fragment presence and a second stage that performs rendering. This segmentation allows the system to execute only the necessary stage (first stage) for punch through fragments, avoiding unnecessary processing and resource wastage while maintaining rendering capability when needed.
2Productivity
If the shader program is executed completely for punch through fragments, then the fragment can be rendered, but latency increases due to unnecessary processing
Solution Approach 1:
By segmenting the shader program into presence-determination stage and rendering stage, the system can quickly determine fragment presence using only the first stage, reducing processing latency before committing to the more time-consuming second stage of rendering.
Solution Approach 2:
The first stage of the shader program performs preliminary determination of fragment presence before executing the second stage. This preliminary action filters out unnecessary rendering operations for fragments that will not contribute to the final image, reducing overall processing latency.
3Reliability
If depth and tag buffers are updated for all fragments passing depth test, then complete fragment processing is achieved, but resource allocation is wasted for fragments with unknown presence
Solution Approach 1:
The processing pipeline is segmented into two stages where the first stage determines presence and the second stage performs buffer updates. This ensures that depth and tag buffers are updated only for fragments confirmed to be present, improving resource allocation efficiency while maintaining processing completeness through the structured two-stage approach.
Data Source
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AI summary
A compiler configured to analyse a shader program which is for execution in a graphics processing system which comprises: (i) hidden surface removal logic configured to perform hidden surface removal on fragments, and (ii) processing logic configured to execute shader programs for fragments, wherein one or more of the fragments has a shader-dependent property, the compiler being configured to: identify an instruction in the shader program which can affect the shader-dependent property of a fragment; split the shader program into stages by splitting the shader program at a point after the identified instruction in the shader program; and store the stages of the shader program in a memory, wherein the graphics processing system can read the stages of the shader program from the memory.