光線(xiàn)跟蹤算法的研究與實(shí)現(xiàn)
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摘 要

在計(jì)算機(jī)圖形學(xué)中，真實(shí)感技術(shù)占有著重要地位。采用真實(shí)感技術(shù)生成的圖形能夠真實(shí)地反映物體表面的顏色和亮度的細(xì)微變化，表現(xiàn)出物體表面的質(zhì)感。另外還能通過(guò)生成光照下物體的陰影，極大地改善場(chǎng)景的深度感和層次感，充分體現(xiàn)物體間的相互遮擋關(guān)系，并且能夠模擬物體的透明效果和鏡面物體的鏡面效果。
光線(xiàn)跟蹤算法是真實(shí)感生成技術(shù)中的主要算法之一，采用整體光照模型來(lái)模擬場(chǎng)景環(huán)境中的光照情況。光線(xiàn)跟蹤能很自然地解決環(huán)境中所有物體之間的消隱、陰影、鏡面反射和折射等問(wèn)題，并且能夠生成十分逼真的圖形。光線(xiàn)跟蹤算法較難理解，但其實(shí)現(xiàn)相對(duì)簡(jiǎn)單，采用遞歸算法即可。遞歸的光線(xiàn)跟蹤算法計(jì)算量十分巨大，因此應(yīng)盡可能減少求交計(jì)算量是提高光線(xiàn)跟蹤效率的關(guān)鍵。
本文從簡(jiǎn)單的光照模型入手，對(duì)光線(xiàn)跟蹤算法進(jìn)行了一定的研究，重點(diǎn)研究了光線(xiàn)跟蹤算法的原理、光線(xiàn)跟蹤的過(guò)程，以及涉及的求交算法。本文還根據(jù)基本的遞歸光線(xiàn)跟蹤算法原理，結(jié)合windows的圖形設(shè)備接口（GDI），使用C++語(yǔ)言，在MFC框架下實(shí)現(xiàn)了小型的算法演示系統(tǒng)，該系統(tǒng)創(chuàng)建了一個(gè)三維空間場(chǎng)景，并在此場(chǎng)景中放置物體，利用光線(xiàn)跟蹤算法模擬光照效果。

關(guān)鍵詞：真實(shí)感，光線(xiàn)跟蹤，光照模型


Research and Implementation of Ray Tracing Algorithm

Abstract
In computer graphics, the technology of realism plays an important role. The graphics made by realistic technology can reflect minor changes in the surface brightness and colors, which can show the surface texture of an object. By generating the shadow of the light, it improves the sense in depth and gradation of the scene, and reflects the relation of mutual occlusion between objects. Also, realistic technology can simulate transparent objects and mirror effect.
Ray-tracing algorithm is one of the most important algorithms of realistic generation technology. It used a whole light model to simulate the illumination condition of the scene. Ray-tracing can solve all the issues about hiding, shadow, specula reflection and refraction unaffectedly, and can product a very vivid graphics. The ray-tracing algorithm is hard to understand, but it can be achieved by recursion. The amount of calculation of ray-tracing algorithm is very huge. So, how to minimize the intersection calculation is the key to improving efficiency of the ray-tracing algorithm.
Starting with the simple light model, this paper researched the ray-tracing algorithm, including the ray-tracing theory, the procedure of ray tracing, and the algorithms of calculating intersection. Depending on the basic theory of ray-tracing algorithm, this paper realized a small-scale demo under the framework of MFC, using the C++ and Windows GDI. The demo set up a 3D scene, and put some objects in it. Then, it can simulate the illumination effect by ray-tracing algorithm.

Key Words：Realistic, Ray Tracing, Lighting Model


目 錄
畢業(yè)論文原創(chuàng)性聲明..........................................................................................................I
畢業(yè)論文版權(quán)使用授權(quán)...............................................................................................II
摘要................................................................................................................................III
Abstract.........................................................................................................................IV
1 引言...........................................................................................................................1
1.1 課題研究的背景及意義................................................................................1
1.2 國(guó)內(nèi)外研究現(xiàn)狀.............................................................................................1
1.3 本文內(nèi)容與結(jié)構(gòu).............................................................................................2
1.4 本文研究的主要方向.....................................................................................3
2 相關(guān)基礎(chǔ)知識(shí)..............................................................................................................4
2.1 幾何光學(xué)基礎(chǔ)知識(shí)..........................................................................................4
2.2 光線(xiàn)跟蹤相關(guān)基礎(chǔ)..........................................................................................5
2.2.1 光源.......................................................................................................5
2.2.2 環(huán)境光...................................................................................................6
2.2.3 漫反射...................................................................................................7
2.2.4 鏡面反射光...........................................................................................8
2.2.5 Phong光照模型...............................................................................9
2.2.6 整體光照模型......................................................................................11
3 光線(xiàn)跟蹤算法.........................................................................................................13
3.1 光線(xiàn)跟蹤的基本原理....................................................................................13
3.2 本文算法實(shí)現(xiàn)的思想....................................................................................16
4 光線(xiàn)與物體的求交.................................................................................................20
4.1 光線(xiàn)與球的求交............................................................................................20
4.1.1 代數(shù)解法.............................................................................................20
4.1.2 幾何解法.............................................................................................21
4.2 光線(xiàn)與多邊形的求交........................................................................................23
4.3 光線(xiàn)與二次曲面的求交....................................................................................24
4.4 本文程序?qū)崿F(xiàn)的求交算法..............................................................25
5 論文總結(jié).................................................................................................................27
5.1 光線(xiàn)跟蹤算法的后續(xù)研究方向....................................................................27
5.2 輻射度方法....................................................................................................29
5.3 論文結(jié)語(yǔ)........................................................................................................29
致謝..............................................................................................................................33
參考文獻(xiàn)......................................................................................................................34


參考文獻(xiàn)
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