【摘要】：全局光照技術(shù)是真實(shí)感圖形渲染的一種重要技術(shù),傳統(tǒng)的全局光照模型是基于物理的光傳輸模型,在渲染效果上可以做到非常逼真,但是其計(jì)算復(fù)雜性很高,對(duì)于一些實(shí)時(shí)圖形應(yīng)用并不適用。實(shí)時(shí)全局光照是近些年來(lái)發(fā)展較為迅速的一種技術(shù),它從全局光照的組成部分出發(fā),通過(guò)一些特殊技巧來(lái)近似達(dá)到全局光照的效果,環(huán)境光遮擋就是其中一種具有代表性的技術(shù),它通過(guò)計(jì)算場(chǎng)景物體周?chē)膸缀涡畔?lái)確定該物體的遮擋情況,能夠渲染出非常接近真實(shí)的接觸陰影效果,其計(jì)算復(fù)雜度相比傳統(tǒng)全局光照技術(shù)要低很多。但是該技術(shù)依然不能滿足實(shí)時(shí)性要求,對(duì)此人們又提出了環(huán)境光遮擋的各種改進(jìn)算法。屏幕空間環(huán)境光遮擋(SSAO)算法是目前最有效的實(shí)時(shí)全局光照算法之一,在游戲等實(shí)時(shí)3D程序中應(yīng)用廣泛。文中詳細(xì)分析了 SSAO的原理,并給出了其實(shí)現(xiàn)過(guò)程。針對(duì)渲染過(guò)程中的采樣問(wèn)題和重復(fù)計(jì)算的問(wèn)題,人們通過(guò)結(jié)合延遲渲染技術(shù)和改進(jìn)AO計(jì)算方式來(lái)優(yōu)化SSAO。其中具有代表性的是利用幀間相關(guān)性的TSSAO算法。因采樣過(guò)程而導(dǎo)致的噪聲問(wèn)題,通常采用高斯濾波和雙邊濾波進(jìn)行平滑處理,但這兩種方法都有各自的缺點(diǎn),高斯濾波對(duì)于邊緣部分不能很好的保留,使渲染效果不佳,雙邊濾波雖然在邊緣問(wèn)題上處理較好,但在運(yùn)算效率方面任然欠佳。引導(dǎo)濾波技術(shù)在邊緣部分的處理和計(jì)算效率上都要比前兩者出色,我們通過(guò)結(jié)合引導(dǎo)濾波技術(shù),對(duì)渲染紋理階段和后處理階段進(jìn)行改進(jìn),并給出了具體的算法流程。同時(shí)對(duì)比分析了傳統(tǒng)SSAO,TSSAO,結(jié)合引導(dǎo)濾波的SSAO三種算法的優(yōu)劣。從結(jié)果來(lái)看,新方法可以在保持渲染效果的同時(shí)提升渲染效率。
[Abstract]:Global illumination is an important technology of realistic graphics rendering. Traditional global illumination model is based on physical optical transmission model. It can achieve very realistic rendering effect, but its computational complexity is very high. It is not suitable for some real-time graphics applications. It is a kind of technology, which starts from the components of global illumination and achieves the effect of global illumination by some special techniques. Ambient light occlusion is one of the representative technologies. It determines the occlusion of the object by calculating the geometric information around the object in the scene, and can render very close to the real contact shadow. The computational complexity of SSAO is much lower than that of traditional global illumination. However, this technology still can not meet the real-time requirements, so many improved algorithms of ambient light occlusion have been proposed. SSAO is widely used. The principle of SSAO is analyzed in detail and its implementation process is given. In view of the sampling problem and the problem of repeated computation in the rendering process, people optimize SSAO by combining the delay rendering technology with the improved AO calculation method. Gauss filtering and bilateral filtering are usually used to smooth the noise problem, but both of them have their own shortcomings. Gauss filtering can not preserve the edge very well, so the rendering effect is not good. Although bilateral filtering is good at dealing with the edge problem, it still has a poor operational efficiency. The edge processing and computational efficiency are better than the former two. We improve the texture rendering and post-processing stages by combining the bootstrap filtering technology, and give the specific algorithm flow. At the same time, the advantages and disadvantages of traditional SSAO, TSSAO and SSAO combined with bootstrap filtering are compared and analyzed. In order to maintain rendering effect while improving rendering efficiency.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TP391.41

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本文編號(hào)：2228424