臺灣博碩士論文加值系統

摘 要
虛擬群體的應用在各領域裏是相當的廣泛，例如在遊戲、虛擬實境等，而群體的模擬需要大量的角色，同時也帶來驚人的多邊形面數，如何能有效率地顯示這些角色，是一件相當困難的工作。
電腦圖學裡，如何簡化場景以加快著色速度一直是很熱門的課題，本研究使用靜態替代面板的技術取代傳統以幾何結構的方式顯示，加快整個著色的程序，同時也建立一個製作的流程，讓相關從業人員能夠參考使用。
相較於先前其它學者的研究，在貼圖的製作上不採用將全角度貼圖貼在同一張貼圖上，而是將其依攝影機的垂直角度分割成八張，貼圖的讀取則使用一個定位點判斷機制，這樣能夠有效地節省貼圖的使用，同時利用顯示卡的像素著色器在不增加額外貼圖的情況下，讓角色多樣化。

Abstract
The applications of crowd simulation are popular in many different fields such as games and visual reality. The large crowds and complex environment generally brings huge polygons and it is difficult to render those characters in an efficient way.
How to simplify the scenes and accelerate the rendering pipeline is an important topic of computer graphics. This research presents a static impostor rendering system to replace traditional geometric approach and describes a production pipeline for the users in the related domains.
Compared with the previous works which put all textures together, our method generates all viewpoints in eight elevation maps. By doing this, if reduces the usage of textures from exploiting the locator to decide when to load the textures and use the pixel shader on the graphic card to enhance the variety of characters without adding more textures.

目　錄
第一章　緒論 1
1.1　研究背景 1
1.2　研究動機與目的 2
第二章　文獻探討 4
2.1　群體模擬(Crowd simulation) 4
2.1.1　階層式群體系統(ViCrowd) 12
2.1.2　群體筆刷(Crowdbrush) 14
2.1.3　模糊邏輯群體模擬系統(Massive) 16
2.1.4　小結 18
2.2　加速技術(Acceleration techniques) 18
2.2.1　可視性裁切(Visibility Culling) 18
2.2.2　精細度層級(Level of Detail) 19
2.2.3　影像為基礎的著色技術(Image-based rendering) 20
2.3　替代面板(Impostor) 23
2.3.1　替代面板的功能 23
2.3.2　定義替代面板(impostor) 23
2.3.3　靜態的替代面板(Static Impostor) 24
2.3.4　動態的替代面板(Dynamic Impostor) 26
2.3.5　陰影的處理 28
2.3.6　小結 30
第三章　靜態替代面板(Static Impostor)著色系統 31
3.1　前製時期設計(Pre-generated) 31
3.1.1　製作環場圖 31
3.1.2　製作透明遮罩(Alpha matte) 32
3.1.3　使用壓縮格式 34
3.2　執行時期設計(Run time) 35
3.2.1　粒子系統(Particle System) 35
3.2.2　告示板貼圖(Billboard / Sprite) 37
3.2.3　讀取貼圖 44
3.3　著色器程式設計(Shader Programming) 46
3.4　評估設計 47
第四章　實作與效能分析 48
4.1　場景內的人數測試 50
4.2　攝影機高度貼圖測試 51
第五章　結論與建議 53
5.1　結論 53
5.2　研究限制及未來研究建議 53
參考文獻 55

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