Texture Level of Detail Computation Using Lookup Tables

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Solution Overview

Problem

Conventional texture level of detail computations in video graphics are expensive to implement in hardware due to the need for multiplication, square, and square root operations, which complicate texture mapping, especially when objects vary in depth and orientation.

Innovation Solution

A graphic processing system and method that computes texture level of detail using a lookup table and arithmetic operations other than multiplication, square, and square root, simplifying the hardware implementation by rewriting logarithmic equations into integer addition and lookup operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional texture level of detail computation is implemented in hardware, then accurate texture mapping is achieved, but hardware complexity and cost increase due to multiplication, square, and square root operations

Engineering Contradiction:

Improvetexture level of detail accuracyVSAvoidhardware complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive hardware operations (multiplication, square, square root) with cheaper alternatives (addition, lookup tables). The lookup tables pre-compute logarithmic values that would otherwise require complex operations, effectively substituting expensive computational resources with simpler, more hardware-friendly operations while maintaining computational accuracy.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes complex mathematical operations with logarithmic transformations and lookup table queries. By converting multiplication and exponentiation into addition operations through logarithmic identities (log(a*b) = log(a) + log(b)), the patent replaces mechanically complex operations with simpler arithmetic that is more suitable for hardware implementation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If conventional texture level of detail computation is implemented, then accurate LOD calculation is achieved, but computation time and processing cost increase

Engineering Contradiction:

ImproveLOD calculation accuracyVSAvoidcomputation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-computes logarithmic values and stores them in lookup tables before runtime. During actual texture mapping operations, the system simply queries these pre-computed values rather than performing complex calculations in real-time. This preliminary preparation significantly reduces computation time during critical rendering phases while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces time-consuming mathematical operations (multiplication, square, square root) with faster alternatives (addition, table lookup). The lookup table approach converts complex computational tasks into simple memory access and addition operations, dramatically reducing the time required for LOD calculations during rendering.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If multiplication, square, and square root operations are used in texture LOD computation, then computational accuracy is maintained, but hardware implementation cost increases

Engineering Contradiction:

Improvecomputation accuracyVSAvoidhardware implementation ease

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent substitutes complex arithmetic operations with logarithmic transformations and lookup table queries. By using the identity log(exp(x)) = x and log(a^b) = b*log(a), the patent converts expensive operations into cheaper ones that can be implemented more easily in hardware, reducing manufacturing complexity while preserving numerical accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent replaces expensive hardware components required for multiplication and square root operations with simpler alternatives based on addition and lookup tables. This substitution makes hardware implementation more economical and easier to manufacture, as lookup tables can be implemented with simple memory structures rather than complex arithmetic logic units.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP1988509B1Apparatus and method for texture level of detail computation

Publication Date: 2017.01.18 VIVANTE CORP

AI summary

A graphic processing system to compute a texture level of detail. An embodiment of the graphic processing system includes a memory device, a driver, and level of detail computation logic. The memory device is configured to implement a first lookup table. The first lookup table is configured to provide a first level of detail component. The driver is configured to calculate a log value of a second level of detail component. The level of detail computation logic is coupled to the memory device and the driver. The level of detail computation logic is configured to compute a level of detail for a texture mapping operation based on the first level of detail component from the lookup table and the second level of detail component from the driver. Embodiments of the graphic processing system facilitate a simple hardware implementation using operations other than multiplication, square, and square root operations.