• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.45 no.3
• /
• pp.58-67
• /
• 2008

In this paper, we first point out difficulties faced by CG artists in the shading process: (1) a lot of technical details on shaders required, (2) long rendering time, and (3) repeated trials-and-errors. To make them overcome such difficulties, we propose Shader Space Navigator, a system that efficiently searches for shaders similar to a given query shader from a shader database containing a large number of quality shaders. With Shader Space Navigator, CG artists find appropriate shaders from the database that are very close to the final result shader, and thus complete the shading process easily by slightly tuning some attributes of those shaders. Thus, the CG artists can create their final shaders in an intuitive and efficient way without a large number of time-consuming rendering processes. Also, we deal with implementation issues related to Shader Space Navigator and constructing an abundant shader database in detail.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.9
• /
• pp.85-95
• /
• 2008

Characteristically, 3D graphic algorithms have to perform complex calculations on massive amount of stream data. The vertex and pixel shaders have enabled efficient execution of graphic algorithms by hardware, and these graphic processors may seem to have achieved the aim of "hardwarization of software shaders." However, the hardware shaders have hitherto been evolving within the limits of Z-buffer based algorithms. We predict that the ultimate model for future graphic processors will be an algorithm-independent integrated shader which combines the functions of both vertex and pixel shaders. We design the register file model that supports 3-dimensional computer graphic on the programmable unified shader processor. we have verified the accurate calculated value using FPGA Virtex-4(xcvlx200) made by Xilinx for operating binary files made by the implementation progress based on synthesis results.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.1
• /
• pp.145-149
• /
• 2015

A reconfigurable lighting engine for widely used lighting models is proposed for low-power GPU shaders. Conventionally, lighting operations that involve many complex arithmetic operations were calculated by the shader programs on the GPU, which led to a significant energy overhead. In this letter, we propose a lighting engine to improve the energy-efficiency by supporting the widely used advanced lighting models in hardware. It supports the Blinn-Phong, Oren-Nayar, and Cook-Torrance models, by exploiting the logarithmic arithmetic and optimizing the trigonometric function evaluations for the energy-efficiency. Experimental results demonstrate 12.7%, 42.5%, and 35.5% reductions in terms of power-delay product from the shader program implementations for each lighting model. Moreover, our work shows 10.1% higher energy-efficiency for the Blinn-Phong model compared to the prior art.

• ETRI Journal
• /
• v.31 no.4
• /
• pp.429-437
• /
• 2009

This paper proposes a novel technique for 3D scene relighting with interactive viewpoint changes. The proposed technique is based on a deep framebuffer framework for fast relighting computation which adopts image-based techniques to provide arbitrary view-changing. In the preprocessing stage, the shading parameters required for the surface shaders, such as surface color, normal, depth, ambient/diffuse/specular coefficients, and roughness, are cached into multiple deep framebuffers generated by several caching cameras which are created in an automatic manner. When the user designs the lighting setup, the relighting renderer builds a map to connect a screen pixel for the current rendering camera to the corresponding deep framebuffer pixel and then computes illumination at each pixel with the cache values taken from the deep framebuffers. All the relighting computations except the deep framebuffer pre-computation are carried out at interactive rates by the GPU.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2005.05a
• /
• pp.1645-1648
• /
• 2005

PC 그래픽스 하드웨어의 급격한 발전에 따라 슈퍼컴퓨터 또는 여러 대의 컴퓨터를 이용한 병렬/분산 처리로나 가능하였던 실시간 볼륨 렌더링을 한대의 일반 PC에서 수행하려는 시도가 계속되고 있다. PC 그래픽스 하드웨어의 꼭지점 및 픽셀 쉐이더는 수치 계산에 최적화된 벡터 연산으로 빠른 볼륨 렌더링을 가능하게 하였을 뿐만 아니라 기존의 고정된 그래픽스 파이프라인에서 벗어나 사용자가 렌더링 과정에 개입하여 프로그래밍을 할 수 있도록 하였다. 본 논문에서는 이러한 그래픽스 하드웨어의 프로그래밍 기능 중 텍스쳐 좌표의 조작을 이용하여 다양한 종류의 볼륨 데이터를 빠르게 렌더링하고 픽셀 쉐이더의 여러 기능들을 이용하여 퐁 쉐이딩 연산, 이른 깊이 테스트, 팔진트리 텍스쳐등을 구현하여 고품질 영상을 실시간으로 얻고자 하였다.

• Journal of the Korea Computer Graphics Society
• /
• v.8 no.2
• /
• pp.23-29
• /
• 2002

In this paper, we describe an implementation technique that extends the classification and shading capabilities offered by previously reported hardware-assisted volume rendering algorithms. In designing our rendering scheme, we exploited the programmable shader technology supported by the latest consumer PC graphics hardware. Our direct volume rendering technique enables to simultaneously display up to four materials, and to dynamically control gradient magnitude to emphasize or de-emphasize surface boundaries. It can easily create lighting effects such as light source attenuation, depth cueing, and multiple light sources that were often difficult to realize in previous hardware-assisted volume rendering.

• Journal of the Korea Computer Graphics Society
• /
• v.24 no.1
• /
• pp.1-8
• /
• 2018

We propose a modified real-time marching cubes technique that extracts isosurfaces in the form of connected meshes instead of triangle soup. In this way, a various mesh-based isosurface rendering techniques can be implemented and additional information of the isosurfaces such as its topology can be extracted in real-time. In addition, we propose a real-time technique to extract adjacency-triangle structure for geometry shaders that can be used for various shading effects such as silhouette rendering. Compared with the previous technique that welds the output triangles of classical marching cubes, our technique shows up to 300% performance improvement.

• Journal of Korea Game Society
• /
• v.16 no.1
• /
• pp.111-118
• /
• 2016

This paper proposes the mathematical model of Fresnel effect used to illuminate and simulate a surface character model for defense game play. The term illumination is used to represent the process by which the amount of light reaching a surface character model used on game play is determined. The character surface shaders generally use a mathematical model to predict how light will reflect on triangles. The shading normally represents the methods used to determine the color and intensity of light reflected toward the viewer for each pixel representing the character surface model of the game. This model computes the reflection and transmission coefficients and compares simulated results to the Fresnel equations for the real game improvement.

• International Journal of Internet, Broadcasting and Communication
• /
• v.14 no.1
• /
• pp.105-115
• /
• 2022

The platform for displaying cars has been changing with the times. From the popularity of paper media to the rise of computer graphics, the improvement of technology has brought more space and possibilities to the automotive industry. Yiming Zhong proposed the workflow of car configurator through Unreal Engine 4 to implement the basic functions of configuration in 2021, according to Yiming Zhong's final presentation, there is still room to improve the realism of graphics and functionality of the car configurator. Therefore, in this paper we propose to upgrade the car shaders and lighting environments according to the real-world physics and add multi-scenes switching function to car configurator. However the multi-scenes switching function also brings a large amount of data, which leads to the problem of display lag. At the end of the paper, we use the level of details(LOD) process to reduce the amount of data for real-time computing in Unreal Engine 4 and the increase of frames per second(FPS) values verifies the feasibility of our optimization solution.

• The Journal of the Korea Contents Association
• /
• v.20 no.1
• /
• pp.392-402
• /
• 2020

Many modern movies and animations rely heavily on CG (computer graphics). The use of CG has made it possible to produce beyond the limits of visual expression. There has also been an increase in technical and artistic efforts to create new and high quality CGs. Look development is the process of modifying and creating shaders and renderings in 3D to produce CGI (computer-generated imagery) that meets the director's intentions. However, small production or projects may have relatively little or no awareness of look development in the production pipeline. The problems that can occur when look development is not preceded are classified into three categories. first, the shader may react differently under the same lighting conditions. Second, there can be a problem in communication between workers. Third, there is a waste of not promising a look for a given situation. As a way to avoid these problems I studied by creating consistency by the look development system. In the limitation that make it difficult for small studios to do look development because of small workers, time and cost, it is meaningful to study and present a simple look development process that can be carried out by individual or small production.