利用體積表面材質加速位移貼圖研究

Hardware Accelerated Displacement Mapping of Volumetric Surface Textures

近年來，電腦繪圖學領域針對『位移貼圖」技術一直是很熱門的研究，進而發展出影像扭曲的圖形演算法，本研究主要探討支援動態視差的材質貼圖在模型表面上的效果，分析其優缺點對影像描繪的影響，並利用體積表面材質來改善動態視差基於紋理空間的限制。本文採用GPU所支援的繪圖著色器，利用硬體加速將材質貼圖以切片方式重複堆疊成物體表面結構，接著讀取單張法向量貼圖來實現光照模型。此外，本研究針對各層體積表面材質，加入半透明梯度和高度偏移的機制，藉以降低過往需要大量重複堆疊的數目，並有效改善自我遮蔽的鋸齒現象。

In recent years, displacement mapping technology has being an popular research topic in computer graphics, and graphic algorithms called image warping were developed. This study focuses on studying the effect of texture mapping supporting parallax on model surface, analyzing how it's advantages and disadvantages affect image drawing, and using volumetric surface texture to improve parallax's limitation in tangent space. This study uses graphic shaders supported by GPU, utilize hardware acceleration to cut texture mapping into slicing and repeat stacking them to construct model surface structure, then load single normal texture to complete reflection model. Furthermore, this study adds semi-transparency gradient and depth bias mechanism according to volume of each layers of surface texture, and decreases aliasing of occlusion effectively.