shader

In Three.js, I have a 3d object where I am using local clipping planes to only render a part of the object. However, since 3d objects are "hollow" (meaning only the outer surface is rendered), when we clip anything off that surface we can "see into" the object. Here's an example of what I mean, clipping a corner off a cube . Notice how we can see the backside of the opposite corner. I would like to give the appearance of the object being solid. Based on this issue , it seems that the best way to accomplish this is to create a surface over the clipped region, thus capping the hole and making

目录 一、光线追踪概述 1.1 光线追踪是什么 1.2 光线追踪的特点 1.3 光线追踪的历史 1.4 光线追踪的应用 二、光线追踪的原理 2.1 光线追踪的物理原理 2.2 光线追踪算法 2.3 RTX和DXR 2.3.1 RTX（NV） 2.3.2 DXR（Microsoft） 三、UE4的光线追踪 3.1 UE4光线追踪的开启 3.2 UE4光线追踪的特性 3.2.1 光线追踪的阴影 3.2.2 光线追踪的反射 3.2.3 光线追踪的透明 3.2.4 光线追踪的环境光遮蔽 3.2.5 光线追踪的全局光照 3.2.6 光线追踪的其它特性 3.3 UE4光线追踪的调试 3.4 UE4光线追踪的不足 四、UE的底层实现 五、总结 特别说明 参考文献 一、光线追踪概述 1.1 光线追踪是什么 与传统的扫描线或光栅化渲染方式不同， 光线追踪（Ray tracing） 是三维计算机图形学中的特殊渲染算法，跟踪从摄像机发出的光线而不是光源发出的光线，通过这样一项技术生成编排好的场景的数学模型显现出来。 利用光线追踪技术渲染出的照片级画面。 与传统方法的扫描线技术相比，这种方法有更好的光学效果，例如对于反射与折射有更准确的模拟效果，并且效率非常高，所以当追求高质量的效果时经常使用这种方法。 在物理学中，光线追迹可以用来计算光束在介质中传播的情况。在介质中传播时，光束可能会被介质吸收

I am trying to learn Shaders to implement something in my iPhone app. So far I have understood easy examples like making a color image to gray scale, thresholding, etc. Most of the examples involve simple operations in where processing input image pixel I(x,y) results in a simple modification of the colors of the same pixel But, how about Convolutions?. For example, the easiest example would the Gaussian filter, in where output image pixel O(x,y) depends not only on I(x,y) but also on surrounding 8 pixels. O(x,y) = (I(x,y)+ surrounding 8 pixels values)/9; Normally, this cannot be done with one